New materials for hydrogen storage of Li-doped fullerene （C20, C28, C36, C50, C60, C70）-intercalated hexagonal boron nitrogen （h-BN） frameworks were designed by using density functional theory （DFT） calculations...New materials for hydrogen storage of Li-doped fullerene （C20, C28, C36, C50, C60, C70）-intercalated hexagonal boron nitrogen （h-BN） frameworks were designed by using density functional theory （DFT） calculations. First-principles molecular dynamics （MD） simulations showed that the struc- tures of the Cn-BN （n = 20, 28, 36, 50, 60, and 70） frameworks were stable at room temperature. The interlayer distance of the h-BN layers was expanded to 9.96-13.59 A° by the intercalated fullerenes. The hydrogen storage capacities of these three-dimensional （3D） frameworks were studied using grand canonical Monte Carlo （GCMC） simulations. The GCMC results revealed that at 77 K and 100 bar （10 MPa）, the C50-BN framework exhibited the highest gravimetric hydrogen uptake of 6.86 wt% and volumetric hydrogen uptake of 58.01 g/L. Thus, the hydrogen uptake of the Li-doped Cn-intercalated h-BN frameworks was nearly double that of the non-doped framework at room temperature. Furthermore, the isosteric heats of adsorption were in the range of 10-21 kJ/mol, values that are suitable for adsorbing/desorbing the hydrogen molecules at room temperature. At 193 K （-80 ℃） and 100 bar for the Li-doped C50-BN framework, the gravimetric and volumetric uptakes of H2 reached 3.72 wt% and 30.08 g/L, respectively.展开更多
By using the first-principles calculations, the electronic properties of graphene nanoribbon （GNR） doped by boron/nitrogen （B/N） bonded pair are investigated. It is found that B/N bonded pair tends to be doped at ...By using the first-principles calculations, the electronic properties of graphene nanoribbon （GNR） doped by boron/nitrogen （B/N） bonded pair are investigated. It is found that B/N bonded pair tends to be doped at the edges of GNR and B/N pair doping in GNR is easier to carry out than single B doping and unbonded B/N co-doping in GNR. The electronic structure of GNR doped by B/N pair is very sensitive to doping site besides the ribbon width and chirality. Moreover, B/N pair doping can selectively adjust the energy gap of armchair GNR and can induce the semimetal-semiconductor transmission for zigzag GNR. This fact may lead to a possible method for energy band engineering of GNRs and benefit the design of graphene electronic device.展开更多
Oxidized asphaltene （OA）, a thermosetting material with plenty of functional groups, is synthesized from asphaltene （A） using HNO3]HzSO4 as the oxidizing agent. Boron, nitrogen co-doped porous carbon （BNC-OA） is...Oxidized asphaltene （OA）, a thermosetting material with plenty of functional groups, is synthesized from asphaltene （A） using HNO3]HzSO4 as the oxidizing agent. Boron, nitrogen co-doped porous carbon （BNC-OA） is prepared by carbonization of the mixture of boric acid and OA at 1173 K in an argon atmosphere. X-ray photoelectron spectroscopy （XPS） characterization reveals that the BNC-OA has a nitrogen content of 3.26 at.% and a boron content of 1.31 at.%, while its oxidation-free counterpart （BNC-SA） has a nitrogen content of 1.61 at.% and a boron content of 3.02 at.%. The specific surface area and total pore volume of BNC-OA are 1103 m2·g^-1 and 0.921 cm3·g^-1, respectively. At a current density of 0.1 A·g^-1, the specific capacitance of BNC-OA is 335 F·g^-1 and the capacitance retention can still reach 83% at 1 A·g^-1. The analysis shows that the superior electrochemical performance of the BNC-OA is attributed to the pseudocapacitance behavior of surface heteroatom functional groups and an abundant pore-structure. Boron, nitrogen co-doped porous carbon is a promising electrode material for supercapacitors.展开更多
We synthesized and investigated the boron-doped and boron/nitrogen co-doped large single-crystal diamonds grown under high pressure and high temperature(HPHT) conditions(5.9 GPa and 1290℃). The optical and electrical...We synthesized and investigated the boron-doped and boron/nitrogen co-doped large single-crystal diamonds grown under high pressure and high temperature(HPHT) conditions(5.9 GPa and 1290℃). The optical and electrical properties and surface characterization of the synthetic diamonds were observed and studied. Incorporation of nitrogen significantly changed the growth trace on surface of boron-containing diamonds. X-ray photoelectron spectroscopy(XPS) measurements showed good evident that nitrogen atoms successfully incorporate into the boron-rich diamond lattice and bond with carbon atoms. Raman spectra showed differences on the as-grown surfaces and interior between boron-doped and boron/nitrogen co-doped diamonds. Fourier transform infrared spectroscopy(FTIR) measurements indicated that the nitrogen incorporation significantly decreases the boron acceptor concentration in diamonds. Hall measurements at room temperature showed that the carriers concentration of the co-doped diamonds decreases, and the mobility increases obviously. The highest hole mobility of sample BNDD-1 reached 980 cm^(2)·V^(-1)·s^(-1), possible reasons were discussed in the paper.展开更多
In this paper,we report the effect of nitrogen on the deposition and properties of boron doped diamond films synthesized by hot filament chemical vapor deposition.The diamond films consisting of micro-grains(nano-grai...In this paper,we report the effect of nitrogen on the deposition and properties of boron doped diamond films synthesized by hot filament chemical vapor deposition.The diamond films consisting of micro-grains(nano-grains) were realized with low(high) boron source flow rate during the growth processes.The transition of micro-grains to nano-grains is speculated to be strongly(weekly) related with the boron(nitrogen) flow rate.The grain size and Raman spectral feature vary insignificantly as a function of the nitrogen introduction at a certain boron flow rate.The variation of electron field emission characteristics dependent on nitrogen is different between microcrystalline and nanocrystalline boron doped diamond samples,which are related to the combined phase composition,boron doping level and texture structure.There is an optimum nitrogen proportion to improve the field emission properties of the boron-doped films.展开更多
Effects of water stress and foliar boron (FB) application on soybean (Glycine max (L) Merr.) seed composition and nitrogen metabolism have not been well investigated. Therefore, the objective of this study was to inve...Effects of water stress and foliar boron (FB) application on soybean (Glycine max (L) Merr.) seed composition and nitrogen metabolism have not been well investigated. Therefore, the objective of this study was to investigate the effects of water stress and FB on seed protein, oil, fatty acids, nitrate reductase activity (NRA), and nitrogenase activity (NA). A repeated greenhouse experiment was conducted where one set of soybean plants were subjected to water stress (WS), and the other set was watered (W). Foliar boron (B) was applied at rate of 0.45 kg·ha-1. Treatments were watered-plants with no FB (W), watered-plants with FB (WB), water-stress plants with no FB (WS), and water-stress plants with FB (WSB). The results showed that seed protein and oil percentage were significantly (P 15N/ 14N and 13C/12C natural abundance were altered between watered-and watered-stressed plants. These results suggest that water stress and FB can influence seed composition, and nitrogen metabolism, and 15N/14N and 13C/12C ratios, reflecting environmental and metabolic changes in carbon and nitrogen fixation pathways. Lack of B translocation from leaves to seed under water stress may suggest a possible mechanism of limited B translocation under water stress. These findings may be beneficial to breeders to select for B translocation efficiency under drought conditions. Altered 15N/14N and 13C/12C under water stress can be used as a tool to select for drought tolerance using N and C isotopes in the breeding programs.展开更多
The eccentric connectivity index and connective eccentricity index are important topological indices for chemistry. In this paper, we investigate the eccentric connectivity index and connective eccentricity index of b...The eccentric connectivity index and connective eccentricity index are important topological indices for chemistry. In this paper, we investigate the eccentric connectivity index and connective eccentricity index of boron-nitrogen fullerenes, respectively. And we give computing formulas of eccentric connectivity index and connective eccentricity index of all boron-nitrogen fullerenes with regular structure.展开更多
A new type of boron-nitrogen modified fatty acid as water base lube additive was prepared and the chemical structure characterized by infrared spectrum.The tribological properties of the additive in water were evaluat...A new type of boron-nitrogen modified fatty acid as water base lube additive was prepared and the chemical structure characterized by infrared spectrum.The tribological properties of the additive in water were evaluated by friction testers.The morphographies and tribochemical species of the worn surfaces were analyzed by means of X-ray Photoelectron Spectroscope(XPS).The results showed that the additive is excellent in increasing load-carrying capacity,anti-wear and friction-reducing abilities of water.The lubrication mechanism is inferred that a high strength adsorption film and a tribochemical reaction film are formed on the rubbing surfaces due to the carrier effect of the long chain fatty acid molecules,high reaction activities of nitrogen,electron-deficient orbit of boron and their synergisms.展开更多
The present study was based on the general hypothesis that boron may affect the accumulation and utilization of other nutrients in plant. For this purpose a field experiment was carried out to find out the influence o...The present study was based on the general hypothesis that boron may affect the accumulation and utilization of other nutrients in plant. For this purpose a field experiment was carried out to find out the influence of boron on the different nutrients content in FCV tobacco (Nicotiana tabacum L.) at TRS Khan Garhi, Mardan, during 2010-2011. Two varieties TM-2008 and Speight G-28 were tested and six levels of boron (0, 0.5, 1, 2, 3 and 5 kg·ha-1) were applied in the form of boric acid, in randomized complete block design in split plot arrangement and replicated thrice. Results indicated that the yield of tobacco crop increased with 1 kg·B·ha-1 and then decreased sequence wise in both varieties. N and P concentrations were significantly affected by applied boron. Similarly, potassium was increased which is a good indication for a better quality of tobacco crop. Application of boron significantly increased the concentrations of boron nutrients ratios such as K/B;Cl/B and Mn/Fe were decreased while K/Cl and Zn/Cu ratios were increased at lower boron concentrations but decreased at higher concentrations of boron. The fertilizer use efficiency of both the cultivars showed similar trend;however, Speight G-28 was more efficient than TM-2008 in boron accumulation. The overall results revealed that the application of boron should be encouraged for balancing nutrients concentration, thus getting higher yield in the prevailing conditions.展开更多
基金Acknowledgements The authors acknowledge financial support from the National Natural Science Foundation of China （Grant No. 11404042）.
文摘New materials for hydrogen storage of Li-doped fullerene （C20, C28, C36, C50, C60, C70）-intercalated hexagonal boron nitrogen （h-BN） frameworks were designed by using density functional theory （DFT） calculations. First-principles molecular dynamics （MD） simulations showed that the struc- tures of the Cn-BN （n = 20, 28, 36, 50, 60, and 70） frameworks were stable at room temperature. The interlayer distance of the h-BN layers was expanded to 9.96-13.59 A° by the intercalated fullerenes. The hydrogen storage capacities of these three-dimensional （3D） frameworks were studied using grand canonical Monte Carlo （GCMC） simulations. The GCMC results revealed that at 77 K and 100 bar （10 MPa）, the C50-BN framework exhibited the highest gravimetric hydrogen uptake of 6.86 wt% and volumetric hydrogen uptake of 58.01 g/L. Thus, the hydrogen uptake of the Li-doped Cn-intercalated h-BN frameworks was nearly double that of the non-doped framework at room temperature. Furthermore, the isosteric heats of adsorption were in the range of 10-21 kJ/mol, values that are suitable for adsorbing/desorbing the hydrogen molecules at room temperature. At 193 K （-80 ℃） and 100 bar for the Li-doped C50-BN framework, the gravimetric and volumetric uptakes of H2 reached 3.72 wt% and 30.08 g/L, respectively.
基金supported by the Science and Technology Program of Hunan Province,China (Grant No.2010DFJ411)the Natural Science Foundation of Hunan Province,China (Grant No.11JJ4001)the Fundamental Research Funds for the Central Universities,China (Grant No.201012200053)
文摘By using the first-principles calculations, the electronic properties of graphene nanoribbon （GNR） doped by boron/nitrogen （B/N） bonded pair are investigated. It is found that B/N bonded pair tends to be doped at the edges of GNR and B/N pair doping in GNR is easier to carry out than single B doping and unbonded B/N co-doping in GNR. The electronic structure of GNR doped by B/N pair is very sensitive to doping site besides the ribbon width and chirality. Moreover, B/N pair doping can selectively adjust the energy gap of armchair GNR and can induce the semimetal-semiconductor transmission for zigzag GNR. This fact may lead to a possible method for energy band engineering of GNRs and benefit the design of graphene electronic device.
基金Project supported by the National Natural Science Foundation of China(Grant No.21276045)
文摘Oxidized asphaltene （OA）, a thermosetting material with plenty of functional groups, is synthesized from asphaltene （A） using HNO3]HzSO4 as the oxidizing agent. Boron, nitrogen co-doped porous carbon （BNC-OA） is prepared by carbonization of the mixture of boric acid and OA at 1173 K in an argon atmosphere. X-ray photoelectron spectroscopy （XPS） characterization reveals that the BNC-OA has a nitrogen content of 3.26 at.% and a boron content of 1.31 at.%, while its oxidation-free counterpart （BNC-SA） has a nitrogen content of 1.61 at.% and a boron content of 3.02 at.%. The specific surface area and total pore volume of BNC-OA are 1103 m2·g^-1 and 0.921 cm3·g^-1, respectively. At a current density of 0.1 A·g^-1, the specific capacitance of BNC-OA is 335 F·g^-1 and the capacitance retention can still reach 83% at 1 A·g^-1. The analysis shows that the superior electrochemical performance of the BNC-OA is attributed to the pseudocapacitance behavior of surface heteroatom functional groups and an abundant pore-structure. Boron, nitrogen co-doped porous carbon is a promising electrode material for supercapacitors.
基金supported by the National Natural Science Foundation of China (Grant Nos. 51772120, 11704340, 11604246, and 11865005)the Scientific and Technological Project in Henan Province+2 种基金China (Grant No. 202102210198)the Natural Science Foundation of Guangxi (China)(Grant No. 2018GXNSFAA281024)Doctor Start-up Foundation of Guangxi University of Science and Technology (Grant No. 20Z38)。
文摘We synthesized and investigated the boron-doped and boron/nitrogen co-doped large single-crystal diamonds grown under high pressure and high temperature(HPHT) conditions(5.9 GPa and 1290℃). The optical and electrical properties and surface characterization of the synthetic diamonds were observed and studied. Incorporation of nitrogen significantly changed the growth trace on surface of boron-containing diamonds. X-ray photoelectron spectroscopy(XPS) measurements showed good evident that nitrogen atoms successfully incorporate into the boron-rich diamond lattice and bond with carbon atoms. Raman spectra showed differences on the as-grown surfaces and interior between boron-doped and boron/nitrogen co-doped diamonds. Fourier transform infrared spectroscopy(FTIR) measurements indicated that the nitrogen incorporation significantly decreases the boron acceptor concentration in diamonds. Hall measurements at room temperature showed that the carriers concentration of the co-doped diamonds decreases, and the mobility increases obviously. The highest hole mobility of sample BNDD-1 reached 980 cm^(2)·V^(-1)·s^(-1), possible reasons were discussed in the paper.
基金financially supported by The Program for New Century Excellent Talents in University (NCET)the National Natural Science Foundation of China (NSFC) under Grant No.50772041
文摘In this paper,we report the effect of nitrogen on the deposition and properties of boron doped diamond films synthesized by hot filament chemical vapor deposition.The diamond films consisting of micro-grains(nano-grains) were realized with low(high) boron source flow rate during the growth processes.The transition of micro-grains to nano-grains is speculated to be strongly(weekly) related with the boron(nitrogen) flow rate.The grain size and Raman spectral feature vary insignificantly as a function of the nitrogen introduction at a certain boron flow rate.The variation of electron field emission characteristics dependent on nitrogen is different between microcrystalline and nanocrystalline boron doped diamond samples,which are related to the combined phase composition,boron doping level and texture structure.There is an optimum nitrogen proportion to improve the field emission properties of the boron-doped films.
文摘Effects of water stress and foliar boron (FB) application on soybean (Glycine max (L) Merr.) seed composition and nitrogen metabolism have not been well investigated. Therefore, the objective of this study was to investigate the effects of water stress and FB on seed protein, oil, fatty acids, nitrate reductase activity (NRA), and nitrogenase activity (NA). A repeated greenhouse experiment was conducted where one set of soybean plants were subjected to water stress (WS), and the other set was watered (W). Foliar boron (B) was applied at rate of 0.45 kg·ha-1. Treatments were watered-plants with no FB (W), watered-plants with FB (WB), water-stress plants with no FB (WS), and water-stress plants with FB (WSB). The results showed that seed protein and oil percentage were significantly (P 15N/ 14N and 13C/12C natural abundance were altered between watered-and watered-stressed plants. These results suggest that water stress and FB can influence seed composition, and nitrogen metabolism, and 15N/14N and 13C/12C ratios, reflecting environmental and metabolic changes in carbon and nitrogen fixation pathways. Lack of B translocation from leaves to seed under water stress may suggest a possible mechanism of limited B translocation under water stress. These findings may be beneficial to breeders to select for B translocation efficiency under drought conditions. Altered 15N/14N and 13C/12C under water stress can be used as a tool to select for drought tolerance using N and C isotopes in the breeding programs.
文摘The eccentric connectivity index and connective eccentricity index are important topological indices for chemistry. In this paper, we investigate the eccentric connectivity index and connective eccentricity index of boron-nitrogen fullerenes, respectively. And we give computing formulas of eccentric connectivity index and connective eccentricity index of all boron-nitrogen fullerenes with regular structure.
基金National Natural Science Fund(50275147)Chongqing City Tackle Key Problem Sustentation Item(CSTC,2008AC4080)+2 种基金Chongqing City Natural Science FundMinistry of Education"New Century Excellent Person with Ability Sustain Project"Institute Youth Fund.
文摘A new type of boron-nitrogen modified fatty acid as water base lube additive was prepared and the chemical structure characterized by infrared spectrum.The tribological properties of the additive in water were evaluated by friction testers.The morphographies and tribochemical species of the worn surfaces were analyzed by means of X-ray Photoelectron Spectroscope(XPS).The results showed that the additive is excellent in increasing load-carrying capacity,anti-wear and friction-reducing abilities of water.The lubrication mechanism is inferred that a high strength adsorption film and a tribochemical reaction film are formed on the rubbing surfaces due to the carrier effect of the long chain fatty acid molecules,high reaction activities of nitrogen,electron-deficient orbit of boron and their synergisms.
文摘The present study was based on the general hypothesis that boron may affect the accumulation and utilization of other nutrients in plant. For this purpose a field experiment was carried out to find out the influence of boron on the different nutrients content in FCV tobacco (Nicotiana tabacum L.) at TRS Khan Garhi, Mardan, during 2010-2011. Two varieties TM-2008 and Speight G-28 were tested and six levels of boron (0, 0.5, 1, 2, 3 and 5 kg·ha-1) were applied in the form of boric acid, in randomized complete block design in split plot arrangement and replicated thrice. Results indicated that the yield of tobacco crop increased with 1 kg·B·ha-1 and then decreased sequence wise in both varieties. N and P concentrations were significantly affected by applied boron. Similarly, potassium was increased which is a good indication for a better quality of tobacco crop. Application of boron significantly increased the concentrations of boron nutrients ratios such as K/B;Cl/B and Mn/Fe were decreased while K/Cl and Zn/Cu ratios were increased at lower boron concentrations but decreased at higher concentrations of boron. The fertilizer use efficiency of both the cultivars showed similar trend;however, Speight G-28 was more efficient than TM-2008 in boron accumulation. The overall results revealed that the application of boron should be encouraged for balancing nutrients concentration, thus getting higher yield in the prevailing conditions.
