The sulfides and nitrogen compounds in FCC diesel were analyzed by gas chromatography equipped with a pulsed flame photometric detector(GC-PFPD) and gas chromatography coupled with nitrogen chemiluminescence detection...The sulfides and nitrogen compounds in FCC diesel were analyzed by gas chromatography equipped with a pulsed flame photometric detector(GC-PFPD) and gas chromatography coupled with nitrogen chemiluminescence detection(GC-NCD). And the variation of sulfides and nitrogen compounds in FCC diesel produced from gas oil feed hydrotreated at different temperatures was investigated. The test results showed that two main types of sulfur compounds, i.e. benzothiophenes(BTs) and dibenzothiophenes(DBTs) were found in diesel. Nitrogen compounds are mainly composed of non-basic nitrogen compounds, and indoles and carbazoles account for about 98% of the total nitrogen contents. The sulfides in FCC diesel obtained from hydrotreated feed are mainly BTs with a small amount of 4-MDBT and 4,6-DMDBT. With the increase in FCC feed hydrotreating temperature, indoles content in FCC diesel increases, while carbazoles content decreases.展开更多
The density functional theory(DFT)with dispersion corrections was used to study the adsorption behavior of sulfur and nitrogen compounds on NiMoS phase.The calculations were performed based on a hexagonal cluster mode...The density functional theory(DFT)with dispersion corrections was used to study the adsorption behavior of sulfur and nitrogen compounds on NiMoS phase.The calculations were performed based on a hexagonal cluster model including the Mo-edge,the S-edge,and the rarely mentioned corner site.It was found that the adsorption of quinoline is stronger than that of benzothiophene at all the active sites.It indicated the origin of the inhibition effect of nitrogen compounds on HDS.And Ni atoms located around Mo-edge and corner site exhibit higher adsorption selectivity to sulfur compounds than the nitrogen ones.It means that the increase in Ni-promoting effect may weaken the inhibition effect of nitrogen compounds on HDS.展开更多
A custom built dynamic oxygen uptake tester was used to study the influence of nitrogen compounds on the oxidation characteristics of the saturate fractions from mineral base oils. Expermental results indicate that ni...A custom built dynamic oxygen uptake tester was used to study the influence of nitrogen compounds on the oxidation characteristics of the saturate fractions from mineral base oils. Expermental results indicate that nitrogen compounds,especially quinoline and indole,take part in the oxidation of saturates.It is also found that indole is more active than quinoline. The latter can be oxidized partly into ketoimine,and the former is more rapidly oxidized into acylamide.The oxidation products, ketoimine or acylamide, could inhibit the oxidation of the saturates by decomposing hydroperoxide.The influences of indole and quinoline on oxidation of saturates are more complex.For lower nitrogen content, the oxidation processes were accelerated.However, at high nitrogen content, the oxidation induction peroids were increased. The oxidation characteristics of saturates were also dependent on the type of catalysts presented.展开更多
This paper discussed the direction of secondary migration of oil in the No. 6 area of the Melut Basin by making use of nitrogen compounds as secondary oil migration tracers. From the results, we have found that the oc...This paper discussed the direction of secondary migration of oil in the No. 6 area of the Melut Basin by making use of nitrogen compounds as secondary oil migration tracers. From the results, we have found that the occurrence and compositional characteristics of isomeric-nitrogen compounds in crude oil precisely manifest the fractionation effect of oil migration: with increasing secondary migration distance, the absolute concentrations tend to decrease, and the ratio of nitrogen-shielded isomers to nitrogen-exposed isomers tends to increase. It is considered that the main direction of oil migration in the No. 6 area of the Melut Basin is from north to south.展开更多
The nitrogen-containing compounds in Changqing crude oil, its atmospheric residue(AR), and vacuum reside(VR) were characterized by negative and positive ion electrospray ionization(ESI) Fourier transform ion cyclotron...The nitrogen-containing compounds in Changqing crude oil, its atmospheric residue(AR), and vacuum reside(VR) were characterized by negative and positive ion electrospray ionization(ESI) Fourier transform ion cyclotron resonance mass spectrometry(FT-ICR MS). The heteroatom compounds(N_1, N_2, N_1O_1, O_1, and O_2 class species) could be identified by the negative ESI analysis, while the positive mode could only detect the N_1, N_2, and N_1O_1 class species. Among them, the N_1 class species were found to be predominant in crude oil, as confirmed by either negative or positive ESI analyses,which were similar in composition to AR and VR. These compounds with higher abundance were characterized by double bond equivalent(DBE) values and carbon numbers. The composition of these compounds in crude oil and its AR as well as VR was correlated with their different boiling range, DBE values and carbon numbers. The negative ESI analysis showed that the abundant N_1 class species in crude oil and AR were centered at a DBE value of 12, and these species were likely benzocarbazoles, while the N_1 class species with the DBE value ranging from 13 to 16 having more complicated molecular structures were dominant in VR. And the positive ESI analysis gave the information of the abundant N_1 class species in crude oil, AR, and VR having the DBE values in the range of 10, 9―11, and 10―16, respectively, which were likely the compounds with the core of quinoline and benzoquinoline. The analysis confirmed that the distillation process in refinery preferentially removed the low DBE value and low molecular N-class species and brought them into the light and medium distillates, while those N-class species having a high molecular condensation in the molecules with large carbon number remained in the residual oil and could continually affect the downstream oil refining process.展开更多
The interactions of p-dimethylaminobenzaldehyde (p-DAB) and potassium hydrogen sulphate (PHS) in equimolar ratio with various concentration of diphenylamine (solid test material) have been investigated by capillary sp...The interactions of p-dimethylaminobenzaldehyde (p-DAB) and potassium hydrogen sulphate (PHS) in equimolar ratio with various concentration of diphenylamine (solid test material) have been investigated by capillary spot-tests technique in order to investigate the effect of temperature and volume of material in test-tube. The formation of the colored boundary in the capillary is taken for the detection of organic compounds by spot-tests at different temperature and volume of solid test material.展开更多
A one-year study in a typical red soil region of southern China was conducted to determine atmospheric nitrogen (N) fluxes of typical N compounds (NH3, NH4-N, NO3-N, and NO2) and contribution of three sources (gas, ra...A one-year study in a typical red soil region of southern China was conducted to determine atmospheric nitrogen (N) fluxes of typical N compounds (NH3, NH4-N, NO3-N, and NO2) and contribution of three sources (gas, rainwater, and particles) to N deposition. From July 2003 to June 2004, the total atmospheric N deposition was 70.7 kg N ha-1, with dry deposition accounting for 75% of the total deposition. Dry NH3 deposition accounted for 73% of the dry deposition and 55% of the total deposition. Moreover, NO2 contributed 11% of the dry deposition and 8% of the total deposition. Reduced N compounds (NH4+ and NH3) were the predominate contributors, accounting for 66% of the total deposition. Therefore, atmospheric N deposition should be considered when soil acidification and critical loads of atmospheric deposition on soils are estimated.展开更多
The eutectic ionic liquid(EIL) tetraethyl ammonium bromide-malonic acid(TEAB-Mal) was synthesized, with its structure characterized by the FT-IR spectroscopy and the 1 H NMR spectrometry. The performance for removal o...The eutectic ionic liquid(EIL) tetraethyl ammonium bromide-malonic acid(TEAB-Mal) was synthesized, with its structure characterized by the FT-IR spectroscopy and the 1 H NMR spectrometry. The performance for removal of basic nitrogen compounds by EIL was studied using coker diesel as the feedstock. Experimental results showed that the EIL(TEAB-Mal) exhibited a good denitrogenation performance, leading to a 93.6% of basic N-removal efficiency under reaction conditions covering: a temperature of 30 °C, an EIL to oil mass ratio of 1:1, an extraction time of 30 min, and a settling time of 120 min, while the basic nitrogen content in diesel dropped from 580 μg/g to 37 μg/g. In addition, the efficiency for extraction of basic N-compounds could still reach 62.9% at an EIL/oil mass ratio of 1:7 after four recycles of the EIL.展开更多
3,4-Dinitrofurazanfuroxan(DNTF),as a high-energy-density material,features good thermal stability and wide applications.This study aimed to elucidate the thermal decomposition mechanism of DNTF combined with nitrogen-...3,4-Dinitrofurazanfuroxan(DNTF),as a high-energy-density material,features good thermal stability and wide applications.This study aimed to elucidate the thermal decomposition mechanism of DNTF combined with nitrogen-rich compounds containing N-H.The thermal stabilities of DNTF and its hybrid systems were investigated using differential thermal analysis/thermogravimetry(TG),vacuum stability test,and accelerating rate calorimetry under isothermal,non-isothermal,and adiabatic conditions,respectively.Results showed that the thermal stability and thermal safety of DNTF significantly decreased after combining with nitrogen-rich compounds containing N-H.Calculation results showed that the activation energy of the DNTF hybrid systems was significantly lower than that of DNTF.The TGIR was used to monitor the generation of fugitive gases during the thermal decomposition of the DNTF/5-aminotetrazole(5-ATZ)hybrid.Moreover,the nitrogen-rich molecules containing N-H interacted extensively with DNTF,and this interaction accelerated the thermal degradation of DNTF.展开更多
The significant demand for high quality food has motivated us to adopt appropriate processing methods to improve the food nutritional quality and flavors.In this study,the effects of five drying methods,namely,pulsed ...The significant demand for high quality food has motivated us to adopt appropriate processing methods to improve the food nutritional quality and flavors.In this study,the effects of five drying methods,namely,pulsed vacuum drying(PVD),freeze drying(FD),infrared drying(IRD),hot-air drying(HAD)and sun drying(SD)on free amino acids(FAAs),α-dicarbonyl compounds(α-DCs)and volatile compounds(VOCs)in rape bee pollen(RBP)were determined.The results showed that FD significantly released the essential amino acids(EAAs)compared with fresh samples while SD caused the highest loss.Glucosone was the dominantα-DCs in RBP and the highest loss was observed after PVD.Aldehydes were the dominant volatiles of RBP and SD samples contained more new volatile substances(especially aldehydes)than the other four drying methods.Comprehensively,FD and PVD would be potential methods to effectively reduce the quality deterioration of RBP in the drying process.展开更多
Ruminants play a critical role in our food system by converting plant biomass that humans cannot or choose not to consume into edible high-quality food.However,ruminant excreta is a significant source of nitrous oxide...Ruminants play a critical role in our food system by converting plant biomass that humans cannot or choose not to consume into edible high-quality food.However,ruminant excreta is a significant source of nitrous oxide(N_(2)O),a potent greenhouse gas with a long-term global warming potential 298 times that of carbon dioxide.Natural phytochemicals or forages containing phytochemicals have shown the potential to improve the efficiency of nitrogen(N)utilization and decrease N_(2)O emissions from the excreta of ruminants.Dietary inclusion of tannins can shift more of the excreted N to the feces,alter the urinary N composition and consequently reduce N_(2)O emissions from excreta.Essential oils or saponins could inhibit rumen ammonia production and decrease urinary N excretion.In grazed pastures,large amounts of glucosinolates or aucubin can be introduced into pasture soils when animals consume plants rich in these compounds and then excrete them or their metabolites in the urine or feces.If inhibitory compounds are excreted in the urine,they would be directly applied to the urine patch to reduce nitrification and subsequent N_(2)O emissions.The phytochemicals’role in sustainable ruminant production is undeniable,but much uncertainty remains.Inconsistency,transient effects,and adverse effects limit the effectiveness of these phytochemicals for reducing N losses.In this review,we will identify some current phytochemicals found in feed that have the potential to manipulate ruminant N excretion or mitigate N_(2)O production and deliberate the challenges and opportunities associated with using phytochemicals or forages rich in phytochemicals as dietary strategies for reducing N excretion and excreta-derived N_(2)O emissions.展开更多
Background:Whole‐crop wheat(Triticum aestivum)has high nutritive value,and it has become one of the main sources of roughage for ruminants in some countries or regions.This study investigates the effects of no tillag...Background:Whole‐crop wheat(Triticum aestivum)has high nutritive value,and it has become one of the main sources of roughage for ruminants in some countries or regions.This study investigates the effects of no tillage on nitrogen compounds and protease activities of whole‐crop wheat silage.Methods:Wheat was planted on the 9th day(NB9)and 5th day(NB5)before rice harvest and on the first day after rice harvest.Sowing before harvest involved no tillage and sowing after rice harvest involved either no tillage(NA1)or conventional tillage(CK).Results:Compared to CK,the crude protein content of NB9 and NB5 decreased by 16.4%and 9.58%,respectively.With the delay of the sowing date,the contents of non‐protein nitrogen,rapidly degraded protein,and slowly degraded protein in whole‐plant wheat tended to increase.Compared to NA1 wheat silage,the NH_(3)‐N content of NB9 and NB5 silages decreased by 52.7%and 34.4%,respectively.The acid protease activity of NA1 was significantly higher than that of other treatments(p<0.05).Conclusions:There was no significant difference in the degree of protein degradation between NA1 and CK silages.Although the degree of protein degradation in early sowing was low,the degree of fermentation was also weak.展开更多
Nitrogen,one of the most crucial nutrients present in grapes and musts,plays a key role in yeast activities during alcoholic fermentation.Such influences are imposed on yeast growth and fermentation performances inclu...Nitrogen,one of the most crucial nutrients present in grapes and musts,plays a key role in yeast activities during alcoholic fermentation.Such influences are imposed on yeast growth and fermentation performances including the formation of secondary metabolites.Saccharomyces cerevisiae,the main yeast responsible for fermentation,has been studied extensively regarding nitrogen impacts.On the other hand,a similar study for non-Saccharomyces yeasts,whose contributions to winemaking have gradually been acknowledged,remains to be fully explored,with a few studies being reported.This review starts by discussing nitrogen impacts on non-Saccharomyces yeast growth and fermentation kinetics in different case scenarios,then proceeds to summarize the nitrogen preferences of individual yeast strains with regulation mechanisms elucidated by recent studies.Detailed discussions on the influences on the production of volatile compounds and proposed pathways therein are made,followed by future work suggested as the final section.In summarizing the nitrogen impacts on non-Saccharomyces yeasts throughout alcoholic fermentation,this review will be helpful in obtaining a more comprehensive view on these non-conventional wine yeasts in terms of nutrient requirements and corresponding volatile production.Research gaps will therefore be elucidated for future research.展开更多
To provide new insights into the development and utilization of Douchi artificial starters,three common strains(Aspergillus oryzae,Mucor racemosus,and Rhizopus oligosporus)were used to study their influence on the fer...To provide new insights into the development and utilization of Douchi artificial starters,three common strains(Aspergillus oryzae,Mucor racemosus,and Rhizopus oligosporus)were used to study their influence on the fermentation of Douchi.The results showed that the biogenic amine contents of the three types of Douchi were all within the safe range and far lower than those of traditional fermented Douchi.Aspergillus-type Douchi produced more free amino acids than the other two types of Douchi,and its umami taste was more prominent in sensory evaluation(P<0.01),while Mucor-type and Rhizopus-type Douchi produced more esters and pyrazines,making the aroma,sauce,and Douchi flavor more abundant.According to the Pearson and PLS analyses results,sweetness was significantly negatively correlated with phenylalanine,cysteine,and acetic acid(P<0.05),bitterness was significantly negatively correlated with malic acid(P<0.05),the sour taste was significantly positively correlated with citric acid and most free amino acids(P<0.05),while astringency was significantly negatively correlated with glucose(P<0.001).Thirteen volatile compounds such as furfuryl alcohol,phenethyl alcohol,and benzaldehyde caused the flavor difference of three types of Douchi.This study provides theoretical basis for the selection of starting strains for commercial Douchi production.展开更多
Plant growth and resilience to abiotic stresses,such as soil salinity and drought,depend intricately on nitrogen metabolism.This review explores nitrogen’s regulatory role in plant responses to these challenges,unvei...Plant growth and resilience to abiotic stresses,such as soil salinity and drought,depend intricately on nitrogen metabolism.This review explores nitrogen’s regulatory role in plant responses to these challenges,unveiling a dynamic interplay between nitrogen availability and abiotic stress.In the context of soil salinity,a nuanced rela-tionship emerges,featuring both antagonistic and synergistic interactions between salinity and nitrogen levels.Salinity-induced chlorophyll depletion in plants can be alleviated by optimal nitrogen supplementation;however,excessive nitrogen can exacerbate salinity stress.We delve into the complexities of this interaction and its agri-cultural implications.Nitrogen,a vital element within essential plant structures like chloroplasts,elicits diverse responses based on its availability.This review comprehensively examines manifestations of nitrogen deficiency and toxicity across various crop types,including cereals,vegetables,legumes,and fruits.Furthermore,we explore the broader consequences of nitrogen products,such as N_(2)O,NO_(2),and ammonia,on human health.Understand-ing the intricate relationship between nitrogen and salinity,especially chloride accumulation in nitrate-fed plants and sodium buildup in ammonium-fed plants,is pivotal for optimizing crop nitrogen management.However,prudent nitrogen use is essential,as overapplication can exacerbate nitrogen-related issues.Nitrogen Use Effi-ciency(NUE)is of paramount importance in addressing salinity challenges and enhancing sustainable crop productivity.Achieving this goal requires advancements in crop varieties with efficient nitrogen utilization,pre-cise timing and placement of nitrogen fertilizer application,and thoughtful nitrogen source selection to mitigate losses,particularly urea-based fertilizer volatilization.This review article delves into the multifaceted world of plant nitrogen metabolism and its pivotal role in enabling plant resilience to nutritional stress and abiotic challenges.It offers insights into future directions for sustainable agriculture.展开更多
This study evaluated the genetic and agronomic parameter estimates of maize under different nitrogen rates. The trial was established at the Njala Agricultural Research Centre experimental site during 2021 and 2022 in...This study evaluated the genetic and agronomic parameter estimates of maize under different nitrogen rates. The trial was established at the Njala Agricultural Research Centre experimental site during 2021 and 2022 in a split block design with three maize varieties (IWCD2, 2009EVDT, and DMR-ESR-Yellow) and seven nitrogen (0, 30, 60, 90, 120, 150 and 180 kg∙N∙ha<sup>−</sup><sup>1</sup>) rates. Findings showed that cob diameter and anthesis silking time (ASI) had intermediate heritability, ASI had high genetic advance, ASI and grain yield had high genotypic coefficient of variation (GCV), while traits with high phenotypic coefficient of variation (PCV) were plant height, ASI, grain yield, number of kernel per cob, number of kernel rows, ear length, and ear height. The PCV values were higher than GCV, indicating the influence of the environment in the studied traits. Nitrogen rates and variety significantly (p < 0.05) influenced grain yield production. Mean grain yields and economic parameter estimates increased with increasing nitrogen rates, with the 30 and 180 kg∙N∙ha<sup>−</sup><sup>1</sup> plots exhibiting the lowest and highest grain yields of 1238 kg∙ha<sup>−</sup><sup>1</sup> and 2098 kg∙ha<sup>−</sup><sup>1</sup>, respectively. Variety and nitrogen effects on partial factor productivity (PFP<sub>N</sub>), agronomic efficiency (AEN), net returns (NR), value cost ratio (VCR) and marginal return (MR) indicated that these parameters were significantly affected (p < 0.05) by these factors. The highest PFP<sub>N</sub> (41.3 kg grain kg<sup>−</sup><sup>1</sup>∙N) and AEN (29.4 kg grain kg<sup>−</sup><sup>1</sup>∙N) were obtained in the 30 kg∙N∙ha<sup>−</sup><sup>1</sup> plots, while the highest VCR (2.8) and MR (SLL 1.8 SLL<sup>−</sup><sup>1</sup> spent on N) were obtained in the 180 kg∙N∙ha<sup>−</sup><sup>1</sup>. The significant influence of variety and nitrogen on traits suggests that increasing yields and maximizing profits require use of appropriate nitrogen fertilization and improved farming practices that could be exploited for increased productivity of maize.展开更多
Plasma nitrogen fixation(PNF)has been emerging as a promising technology for greenhouse gasfree and renewable energy-based agriculture.Yet,most PNF studies seldom address practical application-specific issues.In this ...Plasma nitrogen fixation(PNF)has been emerging as a promising technology for greenhouse gasfree and renewable energy-based agriculture.Yet,most PNF studies seldom address practical application-specific issues.In this work,we present the development of a compact and automatic PNF system for on-site agricultural applications.The system utilized a gliding-arc discharge as the plasma source and employed a dual-loop design to generate NO_(x)from air and water under atmospheric conditions.Experimental results showed that the system with a dualloop design performs well in terms of energy costs and production rates.Optimal operational parameters for the system were determined through experimentation,resulting in an energy cost of 13.9 MJ mol^(-1)and an energy efficiency of 16 g kWh^(-1)for NO_(3)^(-)production,respectively.Moreover,the concentration of exhausted NO_(x)was below the emission standards.Soilless lettuce cultivation experiments demonstrated that NO_(x)^(-)produced by the PNF system could serve as liquid nitrate nitrogen fertilizer.Overall,our work demonstrates the potential of the developed PNF system for on-site application in the production of green-leaf vegetables.展开更多
Tall clonal grasses commonly display competitive advantages with nitrogen(N)enrichment.However,it is currently unknown whether the height is derived from the vegetative or reproductive module.Moreover,it is unclear wh...Tall clonal grasses commonly display competitive advantages with nitrogen(N)enrichment.However,it is currently unknown whether the height is derived from the vegetative or reproductive module.Moreover,it is unclear whether the height of the vegetative or reproductive system regulates the probability of extinction and colonization,and determines species diversity.In this study,the impacts on clonal grasses were studied in a field experiment employing two frequencies(twice a year vs.monthly)crossing with nine N addition rates in a temperate grassland,China.We found that the N addition decreased species frequency and increased extinction probability,but did not change the species colonization probability.A low frequency of N addition decreased species frequency and colonization probability,but increased extinction probability.Moreover,we found that species reproductive height was the best index to predict the extinction probability of clonal grasses in N-enriched conditions.The low frequency of N addition may overestimate the negative effect from N deposition on clonal grass diversity,suggesting that a higher frequency of N addition is more suitable in assessing the ecological effects of N deposition.Overall,this study illustrates that reproductive height was associated with the clonal species extinction probability under N-enriched environment.展开更多
文摘The sulfides and nitrogen compounds in FCC diesel were analyzed by gas chromatography equipped with a pulsed flame photometric detector(GC-PFPD) and gas chromatography coupled with nitrogen chemiluminescence detection(GC-NCD). And the variation of sulfides and nitrogen compounds in FCC diesel produced from gas oil feed hydrotreated at different temperatures was investigated. The test results showed that two main types of sulfur compounds, i.e. benzothiophenes(BTs) and dibenzothiophenes(DBTs) were found in diesel. Nitrogen compounds are mainly composed of non-basic nitrogen compounds, and indoles and carbazoles account for about 98% of the total nitrogen contents. The sulfides in FCC diesel obtained from hydrotreated feed are mainly BTs with a small amount of 4-MDBT and 4,6-DMDBT. With the increase in FCC feed hydrotreating temperature, indoles content in FCC diesel increases, while carbazoles content decreases.
基金We gratefully acknowledge the support from the National Key Research and Development Plan(Grant No.2017YFB0306603)China Petrochemical Corporation funding(Sinopec Group,No.117006)on this work.
文摘The density functional theory(DFT)with dispersion corrections was used to study the adsorption behavior of sulfur and nitrogen compounds on NiMoS phase.The calculations were performed based on a hexagonal cluster model including the Mo-edge,the S-edge,and the rarely mentioned corner site.It was found that the adsorption of quinoline is stronger than that of benzothiophene at all the active sites.It indicated the origin of the inhibition effect of nitrogen compounds on HDS.And Ni atoms located around Mo-edge and corner site exhibit higher adsorption selectivity to sulfur compounds than the nitrogen ones.It means that the increase in Ni-promoting effect may weaken the inhibition effect of nitrogen compounds on HDS.
文摘A custom built dynamic oxygen uptake tester was used to study the influence of nitrogen compounds on the oxidation characteristics of the saturate fractions from mineral base oils. Expermental results indicate that nitrogen compounds,especially quinoline and indole,take part in the oxidation of saturates.It is also found that indole is more active than quinoline. The latter can be oxidized partly into ketoimine,and the former is more rapidly oxidized into acylamide.The oxidation products, ketoimine or acylamide, could inhibit the oxidation of the saturates by decomposing hydroperoxide.The influences of indole and quinoline on oxidation of saturates are more complex.For lower nitrogen content, the oxidation processes were accelerated.However, at high nitrogen content, the oxidation induction peroids were increased. The oxidation characteristics of saturates were also dependent on the type of catalysts presented.
文摘This paper discussed the direction of secondary migration of oil in the No. 6 area of the Melut Basin by making use of nitrogen compounds as secondary oil migration tracers. From the results, we have found that the occurrence and compositional characteristics of isomeric-nitrogen compounds in crude oil precisely manifest the fractionation effect of oil migration: with increasing secondary migration distance, the absolute concentrations tend to decrease, and the ratio of nitrogen-shielded isomers to nitrogen-exposed isomers tends to increase. It is considered that the main direction of oil migration in the No. 6 area of the Melut Basin is from north to south.
基金supported by the Young Talent Fund of University Association for Science and Technoloqy in Shaanxi, China (No. 20160222)The PetroChina Innovation Foundation (No. 2016D-5007-0404)the Natural Science Basic Research Plan in Shaanxi Province of China (No. 2017JQ2034)
文摘The nitrogen-containing compounds in Changqing crude oil, its atmospheric residue(AR), and vacuum reside(VR) were characterized by negative and positive ion electrospray ionization(ESI) Fourier transform ion cyclotron resonance mass spectrometry(FT-ICR MS). The heteroatom compounds(N_1, N_2, N_1O_1, O_1, and O_2 class species) could be identified by the negative ESI analysis, while the positive mode could only detect the N_1, N_2, and N_1O_1 class species. Among them, the N_1 class species were found to be predominant in crude oil, as confirmed by either negative or positive ESI analyses,which were similar in composition to AR and VR. These compounds with higher abundance were characterized by double bond equivalent(DBE) values and carbon numbers. The composition of these compounds in crude oil and its AR as well as VR was correlated with their different boiling range, DBE values and carbon numbers. The negative ESI analysis showed that the abundant N_1 class species in crude oil and AR were centered at a DBE value of 12, and these species were likely benzocarbazoles, while the N_1 class species with the DBE value ranging from 13 to 16 having more complicated molecular structures were dominant in VR. And the positive ESI analysis gave the information of the abundant N_1 class species in crude oil, AR, and VR having the DBE values in the range of 10, 9―11, and 10―16, respectively, which were likely the compounds with the core of quinoline and benzoquinoline. The analysis confirmed that the distillation process in refinery preferentially removed the low DBE value and low molecular N-class species and brought them into the light and medium distillates, while those N-class species having a high molecular condensation in the molecules with large carbon number remained in the residual oil and could continually affect the downstream oil refining process.
文摘The interactions of p-dimethylaminobenzaldehyde (p-DAB) and potassium hydrogen sulphate (PHS) in equimolar ratio with various concentration of diphenylamine (solid test material) have been investigated by capillary spot-tests technique in order to investigate the effect of temperature and volume of material in test-tube. The formation of the colored boundary in the capillary is taken for the detection of organic compounds by spot-tests at different temperature and volume of solid test material.
基金Project supported by the Knowledge Innovation Program of the Chinese Academy of Sciences (No. ISSASIP0205)the National Key Basic Research Support Foundation of China (No. 1999011805)+3 种基金the State Key Laboratory of Soil and Sustainable Agriculture, Chinathe Scientific Research Foundation for Returned Overseas Chinese Scholarsthe State Education Ministry of Chinaand the National Natural Science foundation of China (No. 40305019)
文摘A one-year study in a typical red soil region of southern China was conducted to determine atmospheric nitrogen (N) fluxes of typical N compounds (NH3, NH4-N, NO3-N, and NO2) and contribution of three sources (gas, rainwater, and particles) to N deposition. From July 2003 to June 2004, the total atmospheric N deposition was 70.7 kg N ha-1, with dry deposition accounting for 75% of the total deposition. Dry NH3 deposition accounted for 73% of the dry deposition and 55% of the total deposition. Moreover, NO2 contributed 11% of the dry deposition and 8% of the total deposition. Reduced N compounds (NH4+ and NH3) were the predominate contributors, accounting for 66% of the total deposition. Therefore, atmospheric N deposition should be considered when soil acidification and critical loads of atmospheric deposition on soils are estimated.
基金the financial support from the Doctoral Funds of Liaoning Provincial Natural Science Foundation(201601323)
文摘The eutectic ionic liquid(EIL) tetraethyl ammonium bromide-malonic acid(TEAB-Mal) was synthesized, with its structure characterized by the FT-IR spectroscopy and the 1 H NMR spectrometry. The performance for removal of basic nitrogen compounds by EIL was studied using coker diesel as the feedstock. Experimental results showed that the EIL(TEAB-Mal) exhibited a good denitrogenation performance, leading to a 93.6% of basic N-removal efficiency under reaction conditions covering: a temperature of 30 °C, an EIL to oil mass ratio of 1:1, an extraction time of 30 min, and a settling time of 120 min, while the basic nitrogen content in diesel dropped from 580 μg/g to 37 μg/g. In addition, the efficiency for extraction of basic N-compounds could still reach 62.9% at an EIL/oil mass ratio of 1:7 after four recycles of the EIL.
基金the financially sponsor of the Natural Science Foundation of China(Grant No.51972278)the Outstanding Youth Science and Technology Talents Program of Sichuan(Grant No.19JCQN0085)the Open Project of State Key Laboratory of Environment-friendly Energy Materials(Southwest University of Science and Technology,Grant No.21fksy19)。
文摘3,4-Dinitrofurazanfuroxan(DNTF),as a high-energy-density material,features good thermal stability and wide applications.This study aimed to elucidate the thermal decomposition mechanism of DNTF combined with nitrogen-rich compounds containing N-H.The thermal stabilities of DNTF and its hybrid systems were investigated using differential thermal analysis/thermogravimetry(TG),vacuum stability test,and accelerating rate calorimetry under isothermal,non-isothermal,and adiabatic conditions,respectively.Results showed that the thermal stability and thermal safety of DNTF significantly decreased after combining with nitrogen-rich compounds containing N-H.Calculation results showed that the activation energy of the DNTF hybrid systems was significantly lower than that of DNTF.The TGIR was used to monitor the generation of fugitive gases during the thermal decomposition of the DNTF/5-aminotetrazole(5-ATZ)hybrid.Moreover,the nitrogen-rich molecules containing N-H interacted extensively with DNTF,and this interaction accelerated the thermal degradation of DNTF.
基金supported by National Natural Science Foundation of China(Nos.31871861 and 31501548)The Apicultural Industry Technology System(NCYTI-43-KXJ17)The Science and Technology Innovation Project of Chinese Academy of Agricultural Sciences(CAAS-ASTIP-2015-IAR)。
文摘The significant demand for high quality food has motivated us to adopt appropriate processing methods to improve the food nutritional quality and flavors.In this study,the effects of five drying methods,namely,pulsed vacuum drying(PVD),freeze drying(FD),infrared drying(IRD),hot-air drying(HAD)and sun drying(SD)on free amino acids(FAAs),α-dicarbonyl compounds(α-DCs)and volatile compounds(VOCs)in rape bee pollen(RBP)were determined.The results showed that FD significantly released the essential amino acids(EAAs)compared with fresh samples while SD caused the highest loss.Glucosone was the dominantα-DCs in RBP and the highest loss was observed after PVD.Aldehydes were the dominant volatiles of RBP and SD samples contained more new volatile substances(especially aldehydes)than the other four drying methods.Comprehensively,FD and PVD would be potential methods to effectively reduce the quality deterioration of RBP in the drying process.
基金supported by Beijing Captial Agribusiness&Food Group Co.,Ltd.‘Integrated Innovation and Industrial Application of"Green Digital Intelligence"Technology in the Whole Dairy Industry Chain’(SNSPKJ2022)National Natural Science Foundation of China(32302767).
文摘Ruminants play a critical role in our food system by converting plant biomass that humans cannot or choose not to consume into edible high-quality food.However,ruminant excreta is a significant source of nitrous oxide(N_(2)O),a potent greenhouse gas with a long-term global warming potential 298 times that of carbon dioxide.Natural phytochemicals or forages containing phytochemicals have shown the potential to improve the efficiency of nitrogen(N)utilization and decrease N_(2)O emissions from the excreta of ruminants.Dietary inclusion of tannins can shift more of the excreted N to the feces,alter the urinary N composition and consequently reduce N_(2)O emissions from excreta.Essential oils or saponins could inhibit rumen ammonia production and decrease urinary N excretion.In grazed pastures,large amounts of glucosinolates or aucubin can be introduced into pasture soils when animals consume plants rich in these compounds and then excrete them or their metabolites in the urine or feces.If inhibitory compounds are excreted in the urine,they would be directly applied to the urine patch to reduce nitrification and subsequent N_(2)O emissions.The phytochemicals’role in sustainable ruminant production is undeniable,but much uncertainty remains.Inconsistency,transient effects,and adverse effects limit the effectiveness of these phytochemicals for reducing N losses.In this review,we will identify some current phytochemicals found in feed that have the potential to manipulate ruminant N excretion or mitigate N_(2)O production and deliberate the challenges and opportunities associated with using phytochemicals or forages rich in phytochemicals as dietary strategies for reducing N excretion and excreta-derived N_(2)O emissions.
基金Modern Agricultural Industry Technology System of Guangdong Province,China,Grant/Award Number:2019KJ127Scientific Research Fund Project of Yunnan Provincial Department of Education,China,Grant/Award Number:2023J1205。
文摘Background:Whole‐crop wheat(Triticum aestivum)has high nutritive value,and it has become one of the main sources of roughage for ruminants in some countries or regions.This study investigates the effects of no tillage on nitrogen compounds and protease activities of whole‐crop wheat silage.Methods:Wheat was planted on the 9th day(NB9)and 5th day(NB5)before rice harvest and on the first day after rice harvest.Sowing before harvest involved no tillage and sowing after rice harvest involved either no tillage(NA1)or conventional tillage(CK).Results:Compared to CK,the crude protein content of NB9 and NB5 decreased by 16.4%and 9.58%,respectively.With the delay of the sowing date,the contents of non‐protein nitrogen,rapidly degraded protein,and slowly degraded protein in whole‐plant wheat tended to increase.Compared to NA1 wheat silage,the NH_(3)‐N content of NB9 and NB5 silages decreased by 52.7%and 34.4%,respectively.The acid protease activity of NA1 was significantly higher than that of other treatments(p<0.05).Conclusions:There was no significant difference in the degree of protein degradation between NA1 and CK silages.Although the degree of protein degradation in early sowing was low,the degree of fermentation was also weak.
基金supported by grants from the National Natural Science Foundation of China(32172340)。
文摘Nitrogen,one of the most crucial nutrients present in grapes and musts,plays a key role in yeast activities during alcoholic fermentation.Such influences are imposed on yeast growth and fermentation performances including the formation of secondary metabolites.Saccharomyces cerevisiae,the main yeast responsible for fermentation,has been studied extensively regarding nitrogen impacts.On the other hand,a similar study for non-Saccharomyces yeasts,whose contributions to winemaking have gradually been acknowledged,remains to be fully explored,with a few studies being reported.This review starts by discussing nitrogen impacts on non-Saccharomyces yeast growth and fermentation kinetics in different case scenarios,then proceeds to summarize the nitrogen preferences of individual yeast strains with regulation mechanisms elucidated by recent studies.Detailed discussions on the influences on the production of volatile compounds and proposed pathways therein are made,followed by future work suggested as the final section.In summarizing the nitrogen impacts on non-Saccharomyces yeasts throughout alcoholic fermentation,this review will be helpful in obtaining a more comprehensive view on these non-conventional wine yeasts in terms of nutrient requirements and corresponding volatile production.Research gaps will therefore be elucidated for future research.
基金supported by Special key project of technological innovation and application development in Yongchuan District,Chongqing(2021yc-cxfz20002)the special funds of central government for guiding local science and technology developmentthe funds for the platform projects of professional technology innovation(CSTC2018ZYCXPT0006).
文摘To provide new insights into the development and utilization of Douchi artificial starters,three common strains(Aspergillus oryzae,Mucor racemosus,and Rhizopus oligosporus)were used to study their influence on the fermentation of Douchi.The results showed that the biogenic amine contents of the three types of Douchi were all within the safe range and far lower than those of traditional fermented Douchi.Aspergillus-type Douchi produced more free amino acids than the other two types of Douchi,and its umami taste was more prominent in sensory evaluation(P<0.01),while Mucor-type and Rhizopus-type Douchi produced more esters and pyrazines,making the aroma,sauce,and Douchi flavor more abundant.According to the Pearson and PLS analyses results,sweetness was significantly negatively correlated with phenylalanine,cysteine,and acetic acid(P<0.05),bitterness was significantly negatively correlated with malic acid(P<0.05),the sour taste was significantly positively correlated with citric acid and most free amino acids(P<0.05),while astringency was significantly negatively correlated with glucose(P<0.001).Thirteen volatile compounds such as furfuryl alcohol,phenethyl alcohol,and benzaldehyde caused the flavor difference of three types of Douchi.This study provides theoretical basis for the selection of starting strains for commercial Douchi production.
基金The authors extend their appreciation to the Deanship of Scientific Research at King Khalid University for funding this work through large group research project under Grant Number RGP2/304/44.
文摘Plant growth and resilience to abiotic stresses,such as soil salinity and drought,depend intricately on nitrogen metabolism.This review explores nitrogen’s regulatory role in plant responses to these challenges,unveiling a dynamic interplay between nitrogen availability and abiotic stress.In the context of soil salinity,a nuanced rela-tionship emerges,featuring both antagonistic and synergistic interactions between salinity and nitrogen levels.Salinity-induced chlorophyll depletion in plants can be alleviated by optimal nitrogen supplementation;however,excessive nitrogen can exacerbate salinity stress.We delve into the complexities of this interaction and its agri-cultural implications.Nitrogen,a vital element within essential plant structures like chloroplasts,elicits diverse responses based on its availability.This review comprehensively examines manifestations of nitrogen deficiency and toxicity across various crop types,including cereals,vegetables,legumes,and fruits.Furthermore,we explore the broader consequences of nitrogen products,such as N_(2)O,NO_(2),and ammonia,on human health.Understand-ing the intricate relationship between nitrogen and salinity,especially chloride accumulation in nitrate-fed plants and sodium buildup in ammonium-fed plants,is pivotal for optimizing crop nitrogen management.However,prudent nitrogen use is essential,as overapplication can exacerbate nitrogen-related issues.Nitrogen Use Effi-ciency(NUE)is of paramount importance in addressing salinity challenges and enhancing sustainable crop productivity.Achieving this goal requires advancements in crop varieties with efficient nitrogen utilization,pre-cise timing and placement of nitrogen fertilizer application,and thoughtful nitrogen source selection to mitigate losses,particularly urea-based fertilizer volatilization.This review article delves into the multifaceted world of plant nitrogen metabolism and its pivotal role in enabling plant resilience to nutritional stress and abiotic challenges.It offers insights into future directions for sustainable agriculture.
文摘This study evaluated the genetic and agronomic parameter estimates of maize under different nitrogen rates. The trial was established at the Njala Agricultural Research Centre experimental site during 2021 and 2022 in a split block design with three maize varieties (IWCD2, 2009EVDT, and DMR-ESR-Yellow) and seven nitrogen (0, 30, 60, 90, 120, 150 and 180 kg∙N∙ha<sup>−</sup><sup>1</sup>) rates. Findings showed that cob diameter and anthesis silking time (ASI) had intermediate heritability, ASI had high genetic advance, ASI and grain yield had high genotypic coefficient of variation (GCV), while traits with high phenotypic coefficient of variation (PCV) were plant height, ASI, grain yield, number of kernel per cob, number of kernel rows, ear length, and ear height. The PCV values were higher than GCV, indicating the influence of the environment in the studied traits. Nitrogen rates and variety significantly (p < 0.05) influenced grain yield production. Mean grain yields and economic parameter estimates increased with increasing nitrogen rates, with the 30 and 180 kg∙N∙ha<sup>−</sup><sup>1</sup> plots exhibiting the lowest and highest grain yields of 1238 kg∙ha<sup>−</sup><sup>1</sup> and 2098 kg∙ha<sup>−</sup><sup>1</sup>, respectively. Variety and nitrogen effects on partial factor productivity (PFP<sub>N</sub>), agronomic efficiency (AEN), net returns (NR), value cost ratio (VCR) and marginal return (MR) indicated that these parameters were significantly affected (p < 0.05) by these factors. The highest PFP<sub>N</sub> (41.3 kg grain kg<sup>−</sup><sup>1</sup>∙N) and AEN (29.4 kg grain kg<sup>−</sup><sup>1</sup>∙N) were obtained in the 30 kg∙N∙ha<sup>−</sup><sup>1</sup> plots, while the highest VCR (2.8) and MR (SLL 1.8 SLL<sup>−</sup><sup>1</sup> spent on N) were obtained in the 180 kg∙N∙ha<sup>−</sup><sup>1</sup>. The significant influence of variety and nitrogen on traits suggests that increasing yields and maximizing profits require use of appropriate nitrogen fertilization and improved farming practices that could be exploited for increased productivity of maize.
基金supported by the Science and Technology Project of State Grid Corporation of China(No.5400202133157A-0-0-00)partially supported by the State Grid Gansu Electric Power Company,China。
文摘Plasma nitrogen fixation(PNF)has been emerging as a promising technology for greenhouse gasfree and renewable energy-based agriculture.Yet,most PNF studies seldom address practical application-specific issues.In this work,we present the development of a compact and automatic PNF system for on-site agricultural applications.The system utilized a gliding-arc discharge as the plasma source and employed a dual-loop design to generate NO_(x)from air and water under atmospheric conditions.Experimental results showed that the system with a dualloop design performs well in terms of energy costs and production rates.Optimal operational parameters for the system were determined through experimentation,resulting in an energy cost of 13.9 MJ mol^(-1)and an energy efficiency of 16 g kWh^(-1)for NO_(3)^(-)production,respectively.Moreover,the concentration of exhausted NO_(x)was below the emission standards.Soilless lettuce cultivation experiments demonstrated that NO_(x)^(-)produced by the PNF system could serve as liquid nitrate nitrogen fertilizer.Overall,our work demonstrates the potential of the developed PNF system for on-site application in the production of green-leaf vegetables.
基金supported by a grant from the National Natural Science Foundation of China(grant no.32071603 and 32122055)the Strategic Priority Research Program of the Chinese Academy of Sciences(XDA26020101)。
文摘Tall clonal grasses commonly display competitive advantages with nitrogen(N)enrichment.However,it is currently unknown whether the height is derived from the vegetative or reproductive module.Moreover,it is unclear whether the height of the vegetative or reproductive system regulates the probability of extinction and colonization,and determines species diversity.In this study,the impacts on clonal grasses were studied in a field experiment employing two frequencies(twice a year vs.monthly)crossing with nine N addition rates in a temperate grassland,China.We found that the N addition decreased species frequency and increased extinction probability,but did not change the species colonization probability.A low frequency of N addition decreased species frequency and colonization probability,but increased extinction probability.Moreover,we found that species reproductive height was the best index to predict the extinction probability of clonal grasses in N-enriched conditions.The low frequency of N addition may overestimate the negative effect from N deposition on clonal grass diversity,suggesting that a higher frequency of N addition is more suitable in assessing the ecological effects of N deposition.Overall,this study illustrates that reproductive height was associated with the clonal species extinction probability under N-enriched environment.
