Rechargeable aqueous zinc ion batteries(AZIBs)were considered as one of the most promising candidates for large-scale energy storage due to the merits of high safety and inexpensiveness.As AZIBs cathode material,Mn O_...Rechargeable aqueous zinc ion batteries(AZIBs)were considered as one of the most promising candidates for large-scale energy storage due to the merits of high safety and inexpensiveness.As AZIBs cathode material,Mn O_(2)possesses great merits but was greatly hindered due to the sluggish diffusion kinetic of Zn^(2+) during electrochemical operations.Herein,deep Zn^(2+) ions intercalatedδ-Mn O_(2)(Zn-Mn O_(2))was achieved by the in situ electrochemical deposition route,which significantly enhanced the diffusion ability of Zn^(2+) due to the synergistic effects of Zn^(2+) pillars and structural H;O.The resultant Zn-Mn O_(2)based AZIBs delivers a record capacity of 696 m Ah/g(0.5 m Ah/cm^(2))based on the initial mass loading,which is approaching the theoretical capacity of Mn O_(2)with a two-electrons reaction.In-situ Raman studies reveal highly reversible Zn^(2+)ions insertion/extraction behaviors and here the Zn-Mn O_(2)plays the role of a container during the charge–discharge process.Further charge storage mechanism investigations point out the insertion/extraction of Zn^(2+) and H^(+) coincides,and such process is significantly facilitated results from superior interlayered configurations of Zn-Mn O_(2)The excellent electrochemical performance of Zn-Mn O_(2)achieved in this work suggests the deep ions pre-intercalation strategy may aid in the future development of advanced cathodes for AZIBs.展开更多
Based on the technologies of traditionally mechanical drilling and water jet,we propose a new method of abrasive water jet in combination with rock drilling,and establish a combined rock drilling system for the gas pr...Based on the technologies of traditionally mechanical drilling and water jet,we propose a new method of abrasive water jet in combination with rock drilling,and establish a combined rock drilling system for the gas pre-drainage.This study chose the common sandstone and silicon limestone as the rock sample.A series of experiments were completed in the case of dry drilling,existing technology drilling,combined drilling with high pressure water jet and combined drilling with abrasive water jet,respectively.The drilling efficiency and performance were contrasted and analyzed in detail.The results indicate that it is better to choose the method of combined drilling with the high-pressure water jet for soft rocks.The method of combined drilling with abrasive water jet is feasible for the hard rock drilling and has higher drilling efficiency and performance.In this paper,compared with the existing technology,the drilling depth has increased by about 65%,the axial force and torque have reduced by about 14%and 17%,respectively,and the drill wear reduces obviously in the same conditions.展开更多
Most of the seeds produced by neem （Azadirachta indica A. Juss） trees in Nigeria are currently underutilized. Hence, relevant literature provides only limited information conceming many of the seed oils from this co...Most of the seeds produced by neem （Azadirachta indica A. Juss） trees in Nigeria are currently underutilized. Hence, relevant literature provides only limited information conceming many of the seed oils from this country, especially where it concems the potential applications of these oils as preservatives for ligno-cellulose against bio-deterioration. Using standard procedures therefore, this study was carried out to evaluate and document selected physical and chemical properties of neem seed oil （NSO）, mechanically extracted using a cold press at 31.03 N-mm^-2 pressure and a room temperature of 25 ± 2℃. The results show that oil yield was 38.42% with a specific gravity of 0.91 ± 0.01. The amount of acid was 18.24 ± 1.31 mg KOH.g^-1 and that of iodine 93.12 ± 2.01 g-100 g^- 1, while saponification and peroxide values were 172.88 ± 2.06 and 1.42 ± 0.04 mg·g^-1 respectively. The implication of the values obtained, particularly those for the chemical properties, as they concern the potential application of NSO as a preservative for ligno-eellulose, is likely that it may be useful in this regard since the values may support some of the documented anti-microbial properties of the oil, although other physical and chemical properties that may affect this potential are recommended for investigations. Conclusions and other recommendations follow in line with the results of the study.展开更多
Aqueous sodium-ion batteries(ASIBs) offer significant advantages for energy storage on a large scale,attributed to their economical cost,secure operatio n,and eco-friend ly natu re.Among the leading cathode materials ...Aqueous sodium-ion batteries(ASIBs) offer significant advantages for energy storage on a large scale,attributed to their economical cost,secure operatio n,and eco-friend ly natu re.Among the leading cathode materials for ASIBs,Na_(3)V_(2)(PO_(4))_(3)(NVP) exhibits excellent structural stability and a high Na+diffusion coefficient,making it a promising option.However,the high solubility of vanadium-based materials in aqueous electrolytes engenders suboptimal cycling stability for Na_(3)V_(2)(PO_(4))_(3),constraining its application in ASIBs.Herein,the Cr-substituted Na_(3)V_(1.3)Cr_(0.7)(PO_(4))3@C(NV_(1.3)Cr_(0.7)P) cathode material was synthesized via a simple sol-gel method.It is found that Cr substitution reduces the cell parameters of NV_(1.3)Cr_(0.7)P,effectively reinforcing the crystal structure.Furthermore,NV_(1.3)Cr_(0.7)P alters the Na^(+)insertion/extraction mechanism,transforming the typical two-phase reaction between Na_(1)V_(2)(PO_(4))_(3)and Na_(3)V_(2)(PO_(4))3into continuous solid-solution reactions with stable intermediates.The Cr substitution diminishes the sodium-ion diffusion energy barrier in NV_(1.3)Cr_(0.7)P,leading to smoother Na+insertion and extraction processes.Consequently,NV_(1.3)Cr_(0.7)P exhibits impressive cycling stability,retaining 74.8% of its capacity after 5,000 cycles at a current density of 5 A g^(-1),along with an outstanding rate performance of 79,2% at 10 A g^(-1).This work elucidates the stable Na^(+)insertion/extraction processes in Cr-substituted NV_(1.3)Cr_(0.7)P,offering insights into the application of vanadium-based materials in aqueous sodium-ion batteries.展开更多
基金financially supported by the National Natural Science Foundation of China(Nos.51772138,51572118,and 51601082)the Fundamental Research Funds for the Central Universities(No.lzujbky-2020-59)。
文摘Rechargeable aqueous zinc ion batteries(AZIBs)were considered as one of the most promising candidates for large-scale energy storage due to the merits of high safety and inexpensiveness.As AZIBs cathode material,Mn O_(2)possesses great merits but was greatly hindered due to the sluggish diffusion kinetic of Zn^(2+) during electrochemical operations.Herein,deep Zn^(2+) ions intercalatedδ-Mn O_(2)(Zn-Mn O_(2))was achieved by the in situ electrochemical deposition route,which significantly enhanced the diffusion ability of Zn^(2+) due to the synergistic effects of Zn^(2+) pillars and structural H;O.The resultant Zn-Mn O_(2)based AZIBs delivers a record capacity of 696 m Ah/g(0.5 m Ah/cm^(2))based on the initial mass loading,which is approaching the theoretical capacity of Mn O_(2)with a two-electrons reaction.In-situ Raman studies reveal highly reversible Zn^(2+)ions insertion/extraction behaviors and here the Zn-Mn O_(2)plays the role of a container during the charge–discharge process.Further charge storage mechanism investigations point out the insertion/extraction of Zn^(2+) and H^(+) coincides,and such process is significantly facilitated results from superior interlayered configurations of Zn-Mn O_(2)The excellent electrochemical performance of Zn-Mn O_(2)achieved in this work suggests the deep ions pre-intercalation strategy may aid in the future development of advanced cathodes for AZIBs.
基金supported by the Fundamental Research Funds for the Central University (Nos.CDJZR10248801,CDJZR122488 01)the National Natural Science Foundation of China (No.51104191)
文摘Based on the technologies of traditionally mechanical drilling and water jet,we propose a new method of abrasive water jet in combination with rock drilling,and establish a combined rock drilling system for the gas pre-drainage.This study chose the common sandstone and silicon limestone as the rock sample.A series of experiments were completed in the case of dry drilling,existing technology drilling,combined drilling with high pressure water jet and combined drilling with abrasive water jet,respectively.The drilling efficiency and performance were contrasted and analyzed in detail.The results indicate that it is better to choose the method of combined drilling with the high-pressure water jet for soft rocks.The method of combined drilling with abrasive water jet is feasible for the hard rock drilling and has higher drilling efficiency and performance.In this paper,compared with the existing technology,the drilling depth has increased by about 65%,the axial force and torque have reduced by about 14%and 17%,respectively,and the drill wear reduces obviously in the same conditions.
文摘Most of the seeds produced by neem （Azadirachta indica A. Juss） trees in Nigeria are currently underutilized. Hence, relevant literature provides only limited information conceming many of the seed oils from this country, especially where it concems the potential applications of these oils as preservatives for ligno-cellulose against bio-deterioration. Using standard procedures therefore, this study was carried out to evaluate and document selected physical and chemical properties of neem seed oil （NSO）, mechanically extracted using a cold press at 31.03 N-mm^-2 pressure and a room temperature of 25 ± 2℃. The results show that oil yield was 38.42% with a specific gravity of 0.91 ± 0.01. The amount of acid was 18.24 ± 1.31 mg KOH.g^-1 and that of iodine 93.12 ± 2.01 g-100 g^- 1, while saponification and peroxide values were 172.88 ± 2.06 and 1.42 ± 0.04 mg·g^-1 respectively. The implication of the values obtained, particularly those for the chemical properties, as they concern the potential application of NSO as a preservative for ligno-eellulose, is likely that it may be useful in this regard since the values may support some of the documented anti-microbial properties of the oil, although other physical and chemical properties that may affect this potential are recommended for investigations. Conclusions and other recommendations follow in line with the results of the study.
基金financially supported by the Scientific and Technological Plan Project of Guizhou Province ([2024]054)Additional support came from the Industry and Education Combination Innovation Platform of Intelligent Manufacturing and Graduate Joint Training Base at Guizhou University (2020-520000-83-01324061)the Guizhou Engineering Research Center for Smart Services (2203-520102-04-04-298868)。
文摘Aqueous sodium-ion batteries(ASIBs) offer significant advantages for energy storage on a large scale,attributed to their economical cost,secure operatio n,and eco-friend ly natu re.Among the leading cathode materials for ASIBs,Na_(3)V_(2)(PO_(4))_(3)(NVP) exhibits excellent structural stability and a high Na+diffusion coefficient,making it a promising option.However,the high solubility of vanadium-based materials in aqueous electrolytes engenders suboptimal cycling stability for Na_(3)V_(2)(PO_(4))_(3),constraining its application in ASIBs.Herein,the Cr-substituted Na_(3)V_(1.3)Cr_(0.7)(PO_(4))3@C(NV_(1.3)Cr_(0.7)P) cathode material was synthesized via a simple sol-gel method.It is found that Cr substitution reduces the cell parameters of NV_(1.3)Cr_(0.7)P,effectively reinforcing the crystal structure.Furthermore,NV_(1.3)Cr_(0.7)P alters the Na^(+)insertion/extraction mechanism,transforming the typical two-phase reaction between Na_(1)V_(2)(PO_(4))_(3)and Na_(3)V_(2)(PO_(4))3into continuous solid-solution reactions with stable intermediates.The Cr substitution diminishes the sodium-ion diffusion energy barrier in NV_(1.3)Cr_(0.7)P,leading to smoother Na+insertion and extraction processes.Consequently,NV_(1.3)Cr_(0.7)P exhibits impressive cycling stability,retaining 74.8% of its capacity after 5,000 cycles at a current density of 5 A g^(-1),along with an outstanding rate performance of 79,2% at 10 A g^(-1).This work elucidates the stable Na^(+)insertion/extraction processes in Cr-substituted NV_(1.3)Cr_(0.7)P,offering insights into the application of vanadium-based materials in aqueous sodium-ion batteries.
