The present work aims to stabilize the room temperature allotropic transition of ammonium nitrate(AN)particles utilizing a microencapsulation technique,which involves solvent/non-solvent in which nitrocellulose(NC)has...The present work aims to stabilize the room temperature allotropic transition of ammonium nitrate(AN)particles utilizing a microencapsulation technique,which involves solvent/non-solvent in which nitrocellulose(NC)has been employed as a coating agent.The SEM micrographs revealed distinct features of both pure AN and NC,contrasting with the irregular granular surface topography of the coated AN particles,demonstrating the adherence of NC on the AN surface.Structural analysis via infrared spectroscopy(IR)demonstrated a successful association of AN and NC,with slight shifts observed in IR bands indicating interfacial interactions.Powder X-ray Diffraction(PXRD)analysis further elucidated the structural changes induced by the coating process,revealing that the NC coating altered the crystallization pattern of its pure form.Thermal analysis demonstrates distinct profiles for pure and coated AN,for which the coated sample exhibits a temperature increase and an enthalpy decrease of the room temperature allotropic transition by 6℃,and 36%,respectively.Furthermore,the presence of NC coating alters the intermolecular forces within the composite system,leading to a reduction in melting enthalpy of coated AN by~39%compared to pure AN.The thermal decomposition analysis shows a two-step thermolysis process for coated AN,with a significant increase in the released heat by about 78%accompanied by an increase in the activation barrier of NC and AN thermolysis,demonstrating a stabilized reactivity of the AN-NC particles.These findings highlight the synergistic effect of NC coating on AN particles,which contributed to a structural and reactive stabilization of both AN and NC,proving the potential application of NC-coated AN as a strategically advantageous oxidizer in composite solid propellant formulations.展开更多
Exploding foil initiator(EFI)is a kind of advanced device for initiating explosives,but its function is unstable when it comes to directly igniting pyrotechnics.To solve the problem,this research aims to reveal the ig...Exploding foil initiator(EFI)is a kind of advanced device for initiating explosives,but its function is unstable when it comes to directly igniting pyrotechnics.To solve the problem,this research aims to reveal the ignition mechanism of EFIs directly igniting pyrotechnics.An oscilloscope,a photon Doppler velocimetry,and a plasma spectrum measurement system were employed to obtain information of electric characteristics,impact pressure,and plasma temperature.The results of the electric characteristics and the impact pressure were inconsistent with ignition results.The only thing that the ignition success tests had in common was that their plasma all had a relatively long period of high-temperature duration(HTD).It eventually concludes that the ignition mechanism in this research is the microconvection heat transfer rather than the shock initiation,which differs from that of exploding foil initiators detonating explosives.Furthermore,the methods for evaluating the ignition success of semiconductor bridge initiators are not entirely applicable to the tests mentioned in this paper.The HTD is the critical parameter for judging the ignition success,and it is influenced by two factors:the late time discharge and the energy of the electric explosion.The longer time of the late time discharge and the more energy of the electric explosion,the easier it is to expand the HTD,which improves the probability of the ignition success.展开更多
The nitrate reduction reaction(NtRR)has been demonstrated to be a promising way for obtaining ammonia(NH_(3))by converting NO3-to NH3.Here we report the controlled synthesis of cobalt tetroxide/graphdiyne heterostruct...The nitrate reduction reaction(NtRR)has been demonstrated to be a promising way for obtaining ammonia(NH_(3))by converting NO3-to NH3.Here we report the controlled synthesis of cobalt tetroxide/graphdiyne heterostructured nanowires(Co_(3)O_(4)/GDY NWs)by a simple two-step process including the synthesis of Co_(3)O_(4)NWs and the following growth of GDY using hex-aethynylbenzene as the precursor at 110°C for 10 h.Detailed scanning electron microscopy,high resolution transmission electron microscopy,X-ray photoelectron spectroscopy,and Raman characterization confirmed the synthesis of a Co_(3)O_(4)/GDY heterointerface with the formation of sp-C-Co bonds at the interface and incomplete charge transfer between GDY and Co,which provide a con-tinuous supply of electrons for the catalytic reaction and ensure a rapid NtRR.Because of these advantages,Co_(3)O_(4)/GDY NWs had an excellent NtRR performance with a high NH3 yield rate(YNH3)of 0.78 mmol h^(-1)cm^(-2)and a Faraday efficiency(FE)of 92.45%at-1.05 V(vs.RHE).This work provides a general approach for synthesizing heterostructures that can drive high-performance ammo-nia production from wastewater under ambient conditions.展开更多
Preparation of high purity ruthenium nitrosyl nitrate using spent Ru-Zn/ZrO_(2)catalyst was studied,including melting and leaching to obtain potassium ruthenate solution,reduction,dissolving,concentrating and drying t...Preparation of high purity ruthenium nitrosyl nitrate using spent Ru-Zn/ZrO_(2)catalyst was studied,including melting and leaching to obtain potassium ruthenate solution,reduction,dissolving,concentrating and drying to obtain ruthenium trichloride,nitrosation and hydrolysis to obtain ruthenium nitrosyl hydroxide,removing of K^(+)and Cl^(-),and neutralization with nitric acid.The effects of temperature,concentration,time and pH on the yield and purity of intermediates and final product were studied,and the optimum process conditions were obtained.The yield of ruthenium nitrosyl nitrate is 92%,the content of ruthenium in high purity product is 32.16%,and the content of Cl^(-)and K^(+)are much less than 0.005%.The reaction kinetics of ruthenium nitrosyl chloride to ruthenium nitrosyl hydroxide was studied.The reaction orders of Ru(NO)Cl_(3)at 40,55 and 70℃are 0.39,0.37 and 0.39,respectively,while those of KOH are 0.16,0.15 and 0.17,respectively.The activation energy is-2.33 k J/mol.展开更多
Copper-based catalysts have garnered wide attention in the field of electrocatalytic nitrate reduction for ammonia production due to their low hydrogen precipitation activity and high ammonia selectivity.However,they ...Copper-based catalysts have garnered wide attention in the field of electrocatalytic nitrate reduction for ammonia production due to their low hydrogen precipitation activity and high ammonia selectivity.However,they still face challenges pertaining of poor stability and low activity,which hinder their further application.Herein,we present a Cu_(2)O/Cu heterojunction catalyst supported on nitrogen-doped porous carbon for nitrate reduction.High resolution transmission electron microscopy(HRTEM)and X-ray Diffraction(XRD)results confirm the presence of Cu_(2)O/Cu heterojunctions,which serve as an active phase in catalysis.The nitrogen-doped porous carbon as a carrier not only enhances the catalyst’s stability,but also facilitates the exposure and dispersion of active sites.At-1.29 V(vs.RHE),the maximum production rate of ammonia reaches 8.8 mg/(mg·h)with a Faradaic efficiency of 92.8%.This study also elucidates the effect of Cu_(2)O-to-Cu ratio in the heterojunction on catalytic performance,thereby providing valuable insights for designing efficient nitrate reduction catalysts for ammonia production.展开更多
The nitrate nitrogen removal efficiency of iron-carbon micro-electrolysis system was discussed in treating pharmaceutical wastewater with high nitrogen and refractory organic concentration. The results show that the g...The nitrate nitrogen removal efficiency of iron-carbon micro-electrolysis system was discussed in treating pharmaceutical wastewater with high nitrogen and refractory organic concentration. The results show that the granularity of fillings,pH,volume ratios of iron-carbon and gas-water,and HRT. have significant effects on the nitrogen removal efficiency of iron-carbon micro-electrolysis system. The iron-carbon micro-electrolysis system has a good removal efficiency of pharmaceutical wastewater with high nitrogen and refractory organic concentration when the influent TN,NH4+-N,NO3--N and BOD5/CODCr are 823 mg/L,30 mg/L,793 mg/L and 0.1,respectively,at the granularity of iron and carbon 0.425 mm,pH 3,iron-carbon ratio 3,gas-water ratio 5,HRT 1.5 h,and the removal rates of TN,NH4+-N and NO3--N achieve 51.5%,70% and 50.94%,respectively.展开更多
Ammonium nitrate(AN)is promising oxidizer in green propellants.In this work,the physical coating method was improved to modify the surface of ammonium nitrate particles with different surfactant materials to reduce hy...Ammonium nitrate(AN)is promising oxidizer in green propellants.In this work,the physical coating method was improved to modify the surface of ammonium nitrate particles with different surfactant materials to reduce hygroscopicity.Cetylalcohoi,stearic acid,stearyl alcohol,palmic acid,lauric acid,stearsmide,tetradecylamine,dodecylamine,and tetradecanol were used as coating surfactant agents.The hygroscopicity was tested for ammonium nitrate with and without coating.Fourier transform infrared(FTIR)and scanning electron microscopy(SEM)were used to characterize the surface of coated and uncoated ammonium nitrate.The mass ratio of coating layer and decline of absorption rate of ammonium nitrate coated by cetylalcohol were 1.00%,and 28.40%,respectively.The results indicate that coating with cetylalcohol surfactant have advantages over the other surfactants in term of low mass ratio of coating layer,and high decline of moisture absorption rate.Thus,cetylalcohol would be a promising coating surfactant material for ammonium nitrate.The idea and approach presented in this study have potential to made hydrophobic layer on the surface of particles to reduce hygroscopicity of AN,and also help the researcher to improving anti-hygroscopicity of ammonium salts.展开更多
Some characteristics of nitrate reductase from sugar beet leaves shown in this paper were as follows:The nitrate reductase from sugar beet leaves required NADH as an electron donor.Accordingly,the nitrate reductase wa...Some characteristics of nitrate reductase from sugar beet leaves shown in this paper were as follows:The nitrate reductase from sugar beet leaves required NADH as an electron donor.Accordingly,the nitrate reductase was classified as NADH-dependent(E.C.1 .6.6.1).The Km value of the nitrate reductase for NADH and NO-3 were 0.86 m mol and 0.18μp mol respectively.The optimum pH in reaction mixture solution for nitrate reduction activity was 7.5.The effect of variable concentrations of inorganic phosphorus in the reaction buffer on nitratereductase activity was investigated.When the inorganic phosphorus concentration was below35 mmol,the nitrate reductase activity was increased with increase of inorganic phosphorus concentration.Conversely,when the inorganic phosphorus concentration was Over 35 mmol.the nitrate reductase activity was inhibited.The nitrate reductase activity assayed in vitro was 3.2 and 5.6 times of that assayed in vivo under the condition of exogenous and endogenous ground substance respectively.展开更多
To improve the performance of solid composite propellants(SCPs)supplemented with ammonium nitrate(AN)as an oxidizer,the incorporation of energetic ingredients such as explosives,energetic binders or catalysts is a com...To improve the performance of solid composite propellants(SCPs)supplemented with ammonium nitrate(AN)as an oxidizer,the incorporation of energetic ingredients such as explosives,energetic binders or catalysts is a common effective approach.For this purpose,polyurethane(PU),a typical inert binder,was mixed with nitrocellulose(NC)as an energetic polymer.Numerous composite solid propellant compositions based on AN and NC-modified polyurethane binder with different NC ratios were prepared.The prepared formulations were characterized using Fourier transform infrared spectroscopy(FTIR),RAMAN spectroscopy,X-ray diffraction(XRD),electron densimetry,thermogravimetric(TG)analysis,and differential scanning calorimetry(DSC).A kinetic study was then performed using the iterative KissingerAkahira-Sunose(It-KAS),Flynn-Wall-Ozawa(It-FWO),and non-linear Vyazovkin integral with compensation effect(VYA/CE)methods.The theoretical performances,such as theoretical specific impulse,adiabatic flame temperature,and ideal exhaust gaseous species,were also determined using the NASA Lewis Code,Chemical Equilibrium with Application(CEA).Spectroscopic examinations revealed the existence of NC and full polymerization of PU in the prepared propellants.According to density tests,the density of the propellant increases as the nitrocellulose component increases.According to the thermal analysis and kinetics study,the increase in NC content catalyzed the thermal decomposition of the AN-based composite solid propellants.Based on the theoretical study,increasing the amount of NC in the propellant increased the specific impulse and,as a result,the overall performance.展开更多
The pollution of iron,manganese and nitrate in groundwater is a huge threat to human beings.In this study,column experiments of ceramic,manganese sand,ceramic sand,volcanic rock,quartz sand were conducted.Iron and man...The pollution of iron,manganese and nitrate in groundwater is a huge threat to human beings.In this study,column experiments of ceramic,manganese sand,ceramic sand,volcanic rock,quartz sand were conducted.Iron and manganese contents of influent were 3.3 mg/L and 2.1 mg/L.When the biofilm became mature,the highest iron and manganese removal rate achieved by manganese sand as a filter material.Quartz did a little worse than manganese sand,but other three filter material could not reach展开更多
Wastewater effluents containing phosphorus and nitrogen are major contributors to a variety of water pollution.The present study is therefore aimed at investigating the phosphate and nitrate removal efficiency of thre...Wastewater effluents containing phosphorus and nitrogen are major contributors to a variety of water pollution.The present study is therefore aimed at investigating the phosphate and nitrate removal efficiency of three wastewater protozoa(Aspidisca, Trachelophyllum and Peranema) in a laboratory-scale water treatment system.The system was made of two separate reactors(aerated and non-aerated) and展开更多
NT build 443, or profile fitting method, is often used to measure the diffusion coefficient of chloride in concrete. However, this method is quite laborious and needs special equipment. Colorimetric method is a quick ...NT build 443, or profile fitting method, is often used to measure the diffusion coefficient of chloride in concrete. However, this method is quite laborious and needs special equipment. Colorimetric method is a quick and simple method to measure the penetration depth of chloride by spraying 0.1 mol/L silver nitrate solution. The objective of this work is to study the possibility of the use of colorimetric method in the calculation of non-steady-state diffusion coefficient. Twelve concrete mixtures with different supplementary cementitious materials and water-to-cement ratios of 0.35, 0.48 and 0.6 were used for study. According to NT build 443, the concrete specimens were immersed in 165 g/L NaC1 （2.8 mol/L） solution for 42 d. Both water-soluble （convert to free chloride） chloride and acid-soluble chloride at different layers of specimens were measured. The results show that the mean value of free chloride concentration at the color change boundary Cd was 0.306 mol/L. The surface free chloride concentration cs was obtained by profile fitting method, which was 40% lower than the chloride concentration of exposure solution after an immersion period of 42 d. Chloride diffusion coefficients obtained by the colorimetric method was not well correlated with those obtained by profile fitting method.展开更多
Mutants deficient in nitrate reductase(NR) were classfied into two groups,nia types are deficient in apoprotein and cnx types are lack of Mo-Co.This paper reports the characteristics of low NR mutants,which are not de...Mutants deficient in nitrate reductase(NR) were classfied into two groups,nia types are deficient in apoprotein and cnx types are lack of Mo-Co.This paper reports the characteristics of low NR mutants,which are not deficient in NR activity but 40%～60% of the NR activity of the wild type,Nipponbare.Mutants NR676 and NR827 were selected as seedings showing poor growth with nitrate as sole mitrogen source from M 2 population.They exhibited chlorate resistance.Genetic analysis in the F 1 and F 2 indicated that chlorate resistance in the mutants was transmitted by a single recessive nuclear gene and that NR676 and NR827 were induced by a mutation at a single locus.In the F2 population,all of the seedings showing yellow green leaves were resistant to chlorate and low in NR activity.Photosynthetic rate and mRNA expression of NR676 and NR827 were lower than wild type.These results suggested that low NR activity and chlorate resistance of NR676 and NR827 were caused by a defect in photosynthetic process.展开更多
OBJECTIVE Alzheimer disease(AD)is a leading cause of dementia in elderly individuals and therapeutic options for AD are very limited.Over-activation of N-methyl-D-aspar⁃tate(NMDA)receptors,amyloidβ(Aβ)aggrega⁃tion,a...OBJECTIVE Alzheimer disease(AD)is a leading cause of dementia in elderly individuals and therapeutic options for AD are very limited.Over-activation of N-methyl-D-aspar⁃tate(NMDA)receptors,amyloidβ(Aβ)aggrega⁃tion,a decrease in cerebral blood flow(CBF),and downstream pathological events play impor⁃tant roles in the disease progression of AD.This study seeks to explore the efficacy and mecha⁃nism of action of MN-08,a novel memantine ni⁃trate,in established animal models of AD.METHODS MN-08′s effectiveness as a preventative and therapeutic agent was tested in 2-to 8-month-old APP/PS1 transgenic mice and 9-to 12-month-old 3×Tg-AD mice,respectively.The neuroprotective mechanism of MN-08 was tested in the glutamate cell model.The pharmacokinet⁃ics and safety of MN-08 in vivo were determined in normal rats and beagle dogs.For the behavioral test,Western blotting analysis,pathology,ELISA test and in vitro cell tests,investigators were blinded to the experimental grouping and drug treatment.RESULTS MN-08,a novel meman⁃tine nitrate,was found to inhibit Aβaccumulation,prevent neuronal and dendritic spine loss,and consequently attenuate cognitive deficits in 2-month-old APP/PS1 transgenic mice(for a 6-month preventative course)and in the 8-month-old triple-transgenic(3×Tg-AD)mice(for a 4-month therapeutic course).In vitro,MN-08 could bind to and antagonize NMDA receptors,inhibit the calcium influx,and reverse the dysregula⁃tions of ERK and PI3K/Akt/GSK3βpathway,sub⁃sequently preventing glutamate-induced neuro⁃nal loss.In addition,MN-08 had favorable phar⁃macokinetics,blood-brain barrier penetration,and safety profiles in rats and beagle dogs.CON⁃CLUSION The novel memantine nitrate MN-08 may be a useful therapeutic agent for AD.展开更多
Nitrate Reductase (NR) is a rating-limit and key enzyme of nitrate assimilation in plants,so,NR activity is important for growth,development and the dry matter accumulation of plants.The regulation of NR activity appe...Nitrate Reductase (NR) is a rating-limit and key enzyme of nitrate assimilation in plants,so,NR activity is important for growth,development and the dry matter accumulation of plants.The regulation of NR activity appears to be rather complex and many studies have been devoted to the description of regulation and properties,but in this paper we focus on the properties and regulation of NR in higher plants.展开更多
The electrocatalytic nitrogen oxidation reaction(NOR)is a sustainable approach for converting N_(2)to NO_(3)^(-)under mild conditions.However,it still faces challenges including inefficient N_(2)absorption/activation ...The electrocatalytic nitrogen oxidation reaction(NOR)is a sustainable approach for converting N_(2)to NO_(3)^(-)under mild conditions.However,it still faces challenges including inefficient N_(2)absorption/activation and oxygen evolution competition,sluggish kinetics,low Faradaic efficiency,and limited nitrate yields.In this work,a novel two-dimensional(2D)layered MOF Mn-BCPPy(H_(2)BCPPy=3,5-di(4'-carboxyphenyl)pyridine)has been successfully synthesized.The framework is composed of a rod-manganese motifs and possesses abundant active sites including open metal sites(OMSs)and Lewis base sites(LBSs).The Mn-BCPPy is the first MOF catalyst applied in electrocatalytic NOR which NO_(3)^(-)exhibited relatively high activity with a yield of 99.75μg/(h·mg)and a Faraday efficiency(FE)of 32.09%.Furthermore,it can be used as fluorescent sensor for selectively and sensitively detect nitrofuran antibiotics(NFs).Therefore,this work explores the application of MOF materials in the field of electrocatalytic NOR,which reveals that manganese-based MOFs have great potential prospects.展开更多
Explosion-electricity coupling(EEC) is a technical method to induce electric energy into the plasma material produced by explosion to improve the output of explosion.Exploding foil initiator(EFI) which could produce p...Explosion-electricity coupling(EEC) is a technical method to induce electric energy into the plasma material produced by explosion to improve the output of explosion.Exploding foil initiator(EFI) which could produce plasma during electric explosion can serve as a good carrier for studying the EEC.To investigate the enhancement ability and mechanism of EEC in EFI ignition performance,a kind of EFI chips which could realize the EEC effect was designed and fabricated to observe the characteristics of current and voltage,flyer and plasma temperature during Boron Potassium Nitrate(BPN) ignition of the EFI.It was found that the EEC could enhance EFI ignition in terms of energy utilization,ignition contact surface,and high-temperature sustainability of plasma:firstly,the EEC prolonged the late time discharge(LTD) phase of the electric explosion,making the energy of capacitor effectively utilized;secondly,the EEC could create a larger area of ignition contact surface;last of all,the EEC effect enhanced its hightemperature sustainability by sustaining continuous energy input to plasma.It also was found that the ignition voltage of BPN could be reduced by nearly 600 V under the condition of 0.4 μF capacitance.The research has successfully combined EEC with EFI,revealing the behavioral characteristics of EEC and demonstrating its effective enhancement of EFI ignition.It introduces a new approach to improving EFI output,which is conducive to low-energy ignition of EFI,and expected to take the ignition technology of EFI to a new level.展开更多
This review paper explores the potential of oil palm biomass as a valuable cellulose source for the production of nitrocellulose-based propellants,contributing to the green revolution and sustainable energy solutions....This review paper explores the potential of oil palm biomass as a valuable cellulose source for the production of nitrocellulose-based propellants,contributing to the green revolution and sustainable energy solutions.It highlights the availability of the corresponding biomass in Malaysia and in line with global studies,the chemical compositions,as well as a brief description of current technologies for converting biomass of oil palm into value added products specifically cellulose.Steps to achieve maximum utilization of biomass from oil palm industry for cellulose production and prospective source for nitrocellulose-based propellant are also proposed.The methodology section outlines the pretreatment of lignocellulosic fibres,cellulose extraction,and nitrocellulose production processes.Overall,the review underscores the prospective of palm oil biomass as a sustainable cellulose source for propellant manufacturing,while acknowledging the need for further research and advancements in the field.展开更多
文摘The present work aims to stabilize the room temperature allotropic transition of ammonium nitrate(AN)particles utilizing a microencapsulation technique,which involves solvent/non-solvent in which nitrocellulose(NC)has been employed as a coating agent.The SEM micrographs revealed distinct features of both pure AN and NC,contrasting with the irregular granular surface topography of the coated AN particles,demonstrating the adherence of NC on the AN surface.Structural analysis via infrared spectroscopy(IR)demonstrated a successful association of AN and NC,with slight shifts observed in IR bands indicating interfacial interactions.Powder X-ray Diffraction(PXRD)analysis further elucidated the structural changes induced by the coating process,revealing that the NC coating altered the crystallization pattern of its pure form.Thermal analysis demonstrates distinct profiles for pure and coated AN,for which the coated sample exhibits a temperature increase and an enthalpy decrease of the room temperature allotropic transition by 6℃,and 36%,respectively.Furthermore,the presence of NC coating alters the intermolecular forces within the composite system,leading to a reduction in melting enthalpy of coated AN by~39%compared to pure AN.The thermal decomposition analysis shows a two-step thermolysis process for coated AN,with a significant increase in the released heat by about 78%accompanied by an increase in the activation barrier of NC and AN thermolysis,demonstrating a stabilized reactivity of the AN-NC particles.These findings highlight the synergistic effect of NC coating on AN particles,which contributed to a structural and reactive stabilization of both AN and NC,proving the potential application of NC-coated AN as a strategically advantageous oxidizer in composite solid propellant formulations.
文摘Exploding foil initiator(EFI)is a kind of advanced device for initiating explosives,but its function is unstable when it comes to directly igniting pyrotechnics.To solve the problem,this research aims to reveal the ignition mechanism of EFIs directly igniting pyrotechnics.An oscilloscope,a photon Doppler velocimetry,and a plasma spectrum measurement system were employed to obtain information of electric characteristics,impact pressure,and plasma temperature.The results of the electric characteristics and the impact pressure were inconsistent with ignition results.The only thing that the ignition success tests had in common was that their plasma all had a relatively long period of high-temperature duration(HTD).It eventually concludes that the ignition mechanism in this research is the microconvection heat transfer rather than the shock initiation,which differs from that of exploding foil initiators detonating explosives.Furthermore,the methods for evaluating the ignition success of semiconductor bridge initiators are not entirely applicable to the tests mentioned in this paper.The HTD is the critical parameter for judging the ignition success,and it is influenced by two factors:the late time discharge and the energy of the electric explosion.The longer time of the late time discharge and the more energy of the electric explosion,the easier it is to expand the HTD,which improves the probability of the ignition success.
文摘The nitrate reduction reaction(NtRR)has been demonstrated to be a promising way for obtaining ammonia(NH_(3))by converting NO3-to NH3.Here we report the controlled synthesis of cobalt tetroxide/graphdiyne heterostructured nanowires(Co_(3)O_(4)/GDY NWs)by a simple two-step process including the synthesis of Co_(3)O_(4)NWs and the following growth of GDY using hex-aethynylbenzene as the precursor at 110°C for 10 h.Detailed scanning electron microscopy,high resolution transmission electron microscopy,X-ray photoelectron spectroscopy,and Raman characterization confirmed the synthesis of a Co_(3)O_(4)/GDY heterointerface with the formation of sp-C-Co bonds at the interface and incomplete charge transfer between GDY and Co,which provide a con-tinuous supply of electrons for the catalytic reaction and ensure a rapid NtRR.Because of these advantages,Co_(3)O_(4)/GDY NWs had an excellent NtRR performance with a high NH3 yield rate(YNH3)of 0.78 mmol h^(-1)cm^(-2)and a Faraday efficiency(FE)of 92.45%at-1.05 V(vs.RHE).This work provides a general approach for synthesizing heterostructures that can drive high-performance ammo-nia production from wastewater under ambient conditions.
基金Project(22178392)supported by the National Natural Science Foundation of China。
文摘Preparation of high purity ruthenium nitrosyl nitrate using spent Ru-Zn/ZrO_(2)catalyst was studied,including melting and leaching to obtain potassium ruthenate solution,reduction,dissolving,concentrating and drying to obtain ruthenium trichloride,nitrosation and hydrolysis to obtain ruthenium nitrosyl hydroxide,removing of K^(+)and Cl^(-),and neutralization with nitric acid.The effects of temperature,concentration,time and pH on the yield and purity of intermediates and final product were studied,and the optimum process conditions were obtained.The yield of ruthenium nitrosyl nitrate is 92%,the content of ruthenium in high purity product is 32.16%,and the content of Cl^(-)and K^(+)are much less than 0.005%.The reaction kinetics of ruthenium nitrosyl chloride to ruthenium nitrosyl hydroxide was studied.The reaction orders of Ru(NO)Cl_(3)at 40,55 and 70℃are 0.39,0.37 and 0.39,respectively,while those of KOH are 0.16,0.15 and 0.17,respectively.The activation energy is-2.33 k J/mol.
基金supported by the Fundamental Research Funds for the Central Universities(DUT22LAB601)the Technology Development Contract of Sinopec(123038).
文摘Copper-based catalysts have garnered wide attention in the field of electrocatalytic nitrate reduction for ammonia production due to their low hydrogen precipitation activity and high ammonia selectivity.However,they still face challenges pertaining of poor stability and low activity,which hinder their further application.Herein,we present a Cu_(2)O/Cu heterojunction catalyst supported on nitrogen-doped porous carbon for nitrate reduction.High resolution transmission electron microscopy(HRTEM)and X-ray Diffraction(XRD)results confirm the presence of Cu_(2)O/Cu heterojunctions,which serve as an active phase in catalysis.The nitrogen-doped porous carbon as a carrier not only enhances the catalyst’s stability,but also facilitates the exposure and dispersion of active sites.At-1.29 V(vs.RHE),the maximum production rate of ammonia reaches 8.8 mg/(mg·h)with a Faradaic efficiency of 92.8%.This study also elucidates the effect of Cu_(2)O-to-Cu ratio in the heterojunction on catalytic performance,thereby providing valuable insights for designing efficient nitrate reduction catalysts for ammonia production.
基金Project(2009ZX07315-005) supported by the National Water Pollution Controlled and Treatment Great Special of China
文摘The nitrate nitrogen removal efficiency of iron-carbon micro-electrolysis system was discussed in treating pharmaceutical wastewater with high nitrogen and refractory organic concentration. The results show that the granularity of fillings,pH,volume ratios of iron-carbon and gas-water,and HRT. have significant effects on the nitrogen removal efficiency of iron-carbon micro-electrolysis system. The iron-carbon micro-electrolysis system has a good removal efficiency of pharmaceutical wastewater with high nitrogen and refractory organic concentration when the influent TN,NH4+-N,NO3--N and BOD5/CODCr are 823 mg/L,30 mg/L,793 mg/L and 0.1,respectively,at the granularity of iron and carbon 0.425 mm,pH 3,iron-carbon ratio 3,gas-water ratio 5,HRT 1.5 h,and the removal rates of TN,NH4+-N and NO3--N achieve 51.5%,70% and 50.94%,respectively.
文摘Ammonium nitrate(AN)is promising oxidizer in green propellants.In this work,the physical coating method was improved to modify the surface of ammonium nitrate particles with different surfactant materials to reduce hygroscopicity.Cetylalcohoi,stearic acid,stearyl alcohol,palmic acid,lauric acid,stearsmide,tetradecylamine,dodecylamine,and tetradecanol were used as coating surfactant agents.The hygroscopicity was tested for ammonium nitrate with and without coating.Fourier transform infrared(FTIR)and scanning electron microscopy(SEM)were used to characterize the surface of coated and uncoated ammonium nitrate.The mass ratio of coating layer and decline of absorption rate of ammonium nitrate coated by cetylalcohol were 1.00%,and 28.40%,respectively.The results indicate that coating with cetylalcohol surfactant have advantages over the other surfactants in term of low mass ratio of coating layer,and high decline of moisture absorption rate.Thus,cetylalcohol would be a promising coating surfactant material for ammonium nitrate.The idea and approach presented in this study have potential to made hydrophobic layer on the surface of particles to reduce hygroscopicity of AN,and also help the researcher to improving anti-hygroscopicity of ammonium salts.
文摘Some characteristics of nitrate reductase from sugar beet leaves shown in this paper were as follows:The nitrate reductase from sugar beet leaves required NADH as an electron donor.Accordingly,the nitrate reductase was classified as NADH-dependent(E.C.1 .6.6.1).The Km value of the nitrate reductase for NADH and NO-3 were 0.86 m mol and 0.18μp mol respectively.The optimum pH in reaction mixture solution for nitrate reduction activity was 7.5.The effect of variable concentrations of inorganic phosphorus in the reaction buffer on nitratereductase activity was investigated.When the inorganic phosphorus concentration was below35 mmol,the nitrate reductase activity was increased with increase of inorganic phosphorus concentration.Conversely,when the inorganic phosphorus concentration was Over 35 mmol.the nitrate reductase activity was inhibited.The nitrate reductase activity assayed in vitro was 3.2 and 5.6 times of that assayed in vivo under the condition of exogenous and endogenous ground substance respectively.
文摘To improve the performance of solid composite propellants(SCPs)supplemented with ammonium nitrate(AN)as an oxidizer,the incorporation of energetic ingredients such as explosives,energetic binders or catalysts is a common effective approach.For this purpose,polyurethane(PU),a typical inert binder,was mixed with nitrocellulose(NC)as an energetic polymer.Numerous composite solid propellant compositions based on AN and NC-modified polyurethane binder with different NC ratios were prepared.The prepared formulations were characterized using Fourier transform infrared spectroscopy(FTIR),RAMAN spectroscopy,X-ray diffraction(XRD),electron densimetry,thermogravimetric(TG)analysis,and differential scanning calorimetry(DSC).A kinetic study was then performed using the iterative KissingerAkahira-Sunose(It-KAS),Flynn-Wall-Ozawa(It-FWO),and non-linear Vyazovkin integral with compensation effect(VYA/CE)methods.The theoretical performances,such as theoretical specific impulse,adiabatic flame temperature,and ideal exhaust gaseous species,were also determined using the NASA Lewis Code,Chemical Equilibrium with Application(CEA).Spectroscopic examinations revealed the existence of NC and full polymerization of PU in the prepared propellants.According to density tests,the density of the propellant increases as the nitrocellulose component increases.According to the thermal analysis and kinetics study,the increase in NC content catalyzed the thermal decomposition of the AN-based composite solid propellants.Based on the theoretical study,increasing the amount of NC in the propellant increased the specific impulse and,as a result,the overall performance.
文摘The pollution of iron,manganese and nitrate in groundwater is a huge threat to human beings.In this study,column experiments of ceramic,manganese sand,ceramic sand,volcanic rock,quartz sand were conducted.Iron and manganese contents of influent were 3.3 mg/L and 2.1 mg/L.When the biofilm became mature,the highest iron and manganese removal rate achieved by manganese sand as a filter material.Quartz did a little worse than manganese sand,but other three filter material could not reach
文摘Wastewater effluents containing phosphorus and nitrogen are major contributors to a variety of water pollution.The present study is therefore aimed at investigating the phosphate and nitrate removal efficiency of three wastewater protozoa(Aspidisca, Trachelophyllum and Peranema) in a laboratory-scale water treatment system.The system was made of two separate reactors(aerated and non-aerated) and
基金Project(2010QZZD018) supported by Central South Universtiy,China,and Ghent University,Belgium
文摘NT build 443, or profile fitting method, is often used to measure the diffusion coefficient of chloride in concrete. However, this method is quite laborious and needs special equipment. Colorimetric method is a quick and simple method to measure the penetration depth of chloride by spraying 0.1 mol/L silver nitrate solution. The objective of this work is to study the possibility of the use of colorimetric method in the calculation of non-steady-state diffusion coefficient. Twelve concrete mixtures with different supplementary cementitious materials and water-to-cement ratios of 0.35, 0.48 and 0.6 were used for study. According to NT build 443, the concrete specimens were immersed in 165 g/L NaC1 （2.8 mol/L） solution for 42 d. Both water-soluble （convert to free chloride） chloride and acid-soluble chloride at different layers of specimens were measured. The results show that the mean value of free chloride concentration at the color change boundary Cd was 0.306 mol/L. The surface free chloride concentration cs was obtained by profile fitting method, which was 40% lower than the chloride concentration of exposure solution after an immersion period of 42 d. Chloride diffusion coefficients obtained by the colorimetric method was not well correlated with those obtained by profile fitting method.
文摘Mutants deficient in nitrate reductase(NR) were classfied into two groups,nia types are deficient in apoprotein and cnx types are lack of Mo-Co.This paper reports the characteristics of low NR mutants,which are not deficient in NR activity but 40%～60% of the NR activity of the wild type,Nipponbare.Mutants NR676 and NR827 were selected as seedings showing poor growth with nitrate as sole mitrogen source from M 2 population.They exhibited chlorate resistance.Genetic analysis in the F 1 and F 2 indicated that chlorate resistance in the mutants was transmitted by a single recessive nuclear gene and that NR676 and NR827 were induced by a mutation at a single locus.In the F2 population,all of the seedings showing yellow green leaves were resistant to chlorate and low in NR activity.Photosynthetic rate and mRNA expression of NR676 and NR827 were lower than wild type.These results suggested that low NR activity and chlorate resistance of NR676 and NR827 were caused by a defect in photosynthetic process.
文摘OBJECTIVE Alzheimer disease(AD)is a leading cause of dementia in elderly individuals and therapeutic options for AD are very limited.Over-activation of N-methyl-D-aspar⁃tate(NMDA)receptors,amyloidβ(Aβ)aggrega⁃tion,a decrease in cerebral blood flow(CBF),and downstream pathological events play impor⁃tant roles in the disease progression of AD.This study seeks to explore the efficacy and mecha⁃nism of action of MN-08,a novel memantine ni⁃trate,in established animal models of AD.METHODS MN-08′s effectiveness as a preventative and therapeutic agent was tested in 2-to 8-month-old APP/PS1 transgenic mice and 9-to 12-month-old 3×Tg-AD mice,respectively.The neuroprotective mechanism of MN-08 was tested in the glutamate cell model.The pharmacokinet⁃ics and safety of MN-08 in vivo were determined in normal rats and beagle dogs.For the behavioral test,Western blotting analysis,pathology,ELISA test and in vitro cell tests,investigators were blinded to the experimental grouping and drug treatment.RESULTS MN-08,a novel meman⁃tine nitrate,was found to inhibit Aβaccumulation,prevent neuronal and dendritic spine loss,and consequently attenuate cognitive deficits in 2-month-old APP/PS1 transgenic mice(for a 6-month preventative course)and in the 8-month-old triple-transgenic(3×Tg-AD)mice(for a 4-month therapeutic course).In vitro,MN-08 could bind to and antagonize NMDA receptors,inhibit the calcium influx,and reverse the dysregula⁃tions of ERK and PI3K/Akt/GSK3βpathway,sub⁃sequently preventing glutamate-induced neuro⁃nal loss.In addition,MN-08 had favorable phar⁃macokinetics,blood-brain barrier penetration,and safety profiles in rats and beagle dogs.CON⁃CLUSION The novel memantine nitrate MN-08 may be a useful therapeutic agent for AD.
文摘Nitrate Reductase (NR) is a rating-limit and key enzyme of nitrate assimilation in plants,so,NR activity is important for growth,development and the dry matter accumulation of plants.The regulation of NR activity appears to be rather complex and many studies have been devoted to the description of regulation and properties,but in this paper we focus on the properties and regulation of NR in higher plants.
基金supported by Natural Science Foundation of Shandong Province(ZR2021MB075)Fundamental Research Funds for the Central Universities,Ocean University of China(202461021).
文摘The electrocatalytic nitrogen oxidation reaction(NOR)is a sustainable approach for converting N_(2)to NO_(3)^(-)under mild conditions.However,it still faces challenges including inefficient N_(2)absorption/activation and oxygen evolution competition,sluggish kinetics,low Faradaic efficiency,and limited nitrate yields.In this work,a novel two-dimensional(2D)layered MOF Mn-BCPPy(H_(2)BCPPy=3,5-di(4'-carboxyphenyl)pyridine)has been successfully synthesized.The framework is composed of a rod-manganese motifs and possesses abundant active sites including open metal sites(OMSs)and Lewis base sites(LBSs).The Mn-BCPPy is the first MOF catalyst applied in electrocatalytic NOR which NO_(3)^(-)exhibited relatively high activity with a yield of 99.75μg/(h·mg)and a Faraday efficiency(FE)of 32.09%.Furthermore,it can be used as fluorescent sensor for selectively and sensitively detect nitrofuran antibiotics(NFs).Therefore,this work explores the application of MOF materials in the field of electrocatalytic NOR,which reveals that manganese-based MOFs have great potential prospects.
基金the Science and Technology on Applied Physical Chemistry Laboratory, China (Grant No.6142602220101) to provide fund for conducting experiments。
文摘Explosion-electricity coupling(EEC) is a technical method to induce electric energy into the plasma material produced by explosion to improve the output of explosion.Exploding foil initiator(EFI) which could produce plasma during electric explosion can serve as a good carrier for studying the EEC.To investigate the enhancement ability and mechanism of EEC in EFI ignition performance,a kind of EFI chips which could realize the EEC effect was designed and fabricated to observe the characteristics of current and voltage,flyer and plasma temperature during Boron Potassium Nitrate(BPN) ignition of the EFI.It was found that the EEC could enhance EFI ignition in terms of energy utilization,ignition contact surface,and high-temperature sustainability of plasma:firstly,the EEC prolonged the late time discharge(LTD) phase of the electric explosion,making the energy of capacitor effectively utilized;secondly,the EEC could create a larger area of ignition contact surface;last of all,the EEC effect enhanced its hightemperature sustainability by sustaining continuous energy input to plasma.It also was found that the ignition voltage of BPN could be reduced by nearly 600 V under the condition of 0.4 μF capacitance.The research has successfully combined EEC with EFI,revealing the behavioral characteristics of EEC and demonstrating its effective enhancement of EFI ignition.It introduces a new approach to improving EFI output,which is conducive to low-energy ignition of EFI,and expected to take the ignition technology of EFI to a new level.
基金Financial support from Universiti Pertahanan Nasional Malaysia,Malaysia for Tabung Amanah PPPI (Defence Research Institute,UPNM)grant-A0014 (UPNM/2023/GPPP/SG/2)funded by Universiti Pertahanan Nasional Malaysia (UPNM),situated in Malaysia+1 种基金This financial backing was made possible through the"Tabung Amanah PPPI"grant,which is affiliated with UPNM’s Defence Research Institutethe grant is identifiable by its unique reference number,"A0014 (UPNM/2023/GPPP/SG/2)"。
文摘This review paper explores the potential of oil palm biomass as a valuable cellulose source for the production of nitrocellulose-based propellants,contributing to the green revolution and sustainable energy solutions.It highlights the availability of the corresponding biomass in Malaysia and in line with global studies,the chemical compositions,as well as a brief description of current technologies for converting biomass of oil palm into value added products specifically cellulose.Steps to achieve maximum utilization of biomass from oil palm industry for cellulose production and prospective source for nitrocellulose-based propellant are also proposed.The methodology section outlines the pretreatment of lignocellulosic fibres,cellulose extraction,and nitrocellulose production processes.Overall,the review underscores the prospective of palm oil biomass as a sustainable cellulose source for propellant manufacturing,while acknowledging the need for further research and advancements in the field.
