By using AP-FIM the varity of the ordered degree of Ni_3Al with L1_2 structure with B content was studied. The possibility of boron improving ductility was also discussed from bonding between Ni and Al atoms, and anti...By using AP-FIM the varity of the ordered degree of Ni_3Al with L1_2 structure with B content was studied. The possibility of boron improving ductility was also discussed from bonding between Ni and Al atoms, and antisite defects in Ni_3Al. The extent of ordering is reduced with an increase in boron content and the autisite defects are most obvious for 0.52at.K B-doped sample that has the best ductility. Some results were verified by X-ray diffraction non. The addition of boron not only influences electron environment at grain boundary but also in the interior of Ni_3Al gm ins, the latter is favorable to improve the ductility of Ni_3Al grains.展开更多
Several concepts of the grain refinement mechanism of B on hypoeutectic Al-Si alloys have been adopted: the refining effect of B on the a-AI and eutectic Si with the different additions of Al-B master alloys made at ...Several concepts of the grain refinement mechanism of B on hypoeutectic Al-Si alloys have been adopted: the refining effect of B on the a-AI and eutectic Si with the different additions of Al-B master alloys made at 850℃ was investigated; and the Al-B master alloys formed under different temperature conditions have been studied to explore the morphologies of AIB2 particles; slowly cooled sample with addition of Al-B was made to explore the refinement mechanism. AI-B master alloy can refine not only a-AI, but eutectic Si. Theoretical analysis indicates that, although AIB2 does not take part directly in the nucleation process in pure Al in the presence of Si, it provides a substrate for precipitation of a small content of Si from which a-At will grow without any undercooling. When the temperature decreases to eutectic line, AIB2 subsequently nucleates eutectic Si; AIB2 particles appear in two different morphologies, namely, hexagonal platelet and tetradehedron morphology which depend on the processing temperature conditions.展开更多
Hydrogenated silicon carbide films (SiC:H) were deposited using the electron cyclotron resonance chemical vapour deposition (ECR-CVD) technique from a mixture of methane, silane and hydrogen, and using diborane and ph...Hydrogenated silicon carbide films (SiC:H) were deposited using the electron cyclotron resonance chemical vapour deposition (ECR-CVD) technique from a mixture of methane, silane and hydrogen, and using diborane and phosphine as doping gases. The effects of changes in the microwave power on the deposition rate and optical bandgap were investigated, and variations in the photoand dark-conductivities and activation energy were studied in conjunction with film analysis using the Raman scattering technique. In the case of boron-doped samples, the conductivity increased rapidly to a maximum, followed by rapid reduction at high microwave power. The ratio of the photo- to dark-conductivity (σph/σd) peaked at microwave power of ~600 W. Under conditions of high microwave power, Raman scattering analysis showed evidence of the formation and increase in the silicon microcrystalline and diamond-like phases in the films, the former of which could account for the rapid increase and the latter the subsequent decrease in the conductivity.In the case of phosphorusdoped SiC:H samples, it was found that increase in the microwave power has the effect of enhancing the formation of the silicon microcrystalline phase in the films which occurred in correspondence to a rapid increase in the conductivity and reduction in the activation energy The conductivity increase stabilised in samples deposited at microwave power exceeding 500 W probably as a result of dopant saturation. Results from Raman scattering measurements also showed that phosphorus doping had the effect of enhancing the formation of the silicon microcrystals in the film whereas the presence of boron had the effect of preserving the amorphous structure.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
Purpose: In defining the biological effects of the 10B(n, α)7Li neutron capture reaction, we have previously developed a deterministic parsing model to determine the Compound Biological Effectiveness (CBE) factor in ...Purpose: In defining the biological effects of the 10B(n, α)7Li neutron capture reaction, we have previously developed a deterministic parsing model to determine the Compound Biological Effectiveness (CBE) factor in Borono-Phenyl-Alanine (BPA)-mediated Boron Neutron Capture Therapy (BNCT). In present paper, we demonstrate that the CBE factor is directly and unambiguously derivable by the new formula for any case of intracellular 10Boron (10B) distribution, which is founded on this model for tissues and tumor. Method: To determine the CBE factor, we derive the following new calculation formula founded on the deterministic parsing model with three constants, CBE0, F, n and the eigen value Nth/Nmax. where, Nth and Nmax are the threshold value of boron concentration of N and saturation boron density in tissues and tumor. In order to determine these constants and the eigen values, iterative calculation technique was employed for the CEB factor and Nmax data set previously reported. Results and Conclusion: From the iterative calculation results, it is clear that the calculated CBE factor values obtained are almost identical to the original CBE factors and there is a good correlation between the original CBE factors and Nth/Nmax, when CBE0, F and n are given as 0.5, 8 and 3, respectively. These constants provide a better understanding of different types of intracellular10B distribution.展开更多
The segregation and diffusion of boron during heat treatments were studied. The influence of boron contents, aging time and applied stress on FeMo2B2 formation was also studied. Finally, the effects of boron contents ...The segregation and diffusion of boron during heat treatments were studied. The influence of boron contents, aging time and applied stress on FeMo2B2 formation was also studied. Finally, the effects of boron contents and FeMo2B2 formation on the high temperature strength were studied. Boron atoms were segregated to prior austenite grain boundary during normalizing treatment. And these boron atoms were slowly diffused into the grain interior during tempering and aging at 700 ℃. The FeMo2B2 phase was only formed after 1,000 h aging at 700 ℃ in alloy containing 196 ppm boron. The formation of FeMo2B2 phase is accelerated by the applied stress. It was expected that the formation of FeMo2B2 is closely related to the redistribution of boron atoms. The tensile strengths at 700 ℃ are increased with the increase of boron contents. However, the formation of FeMo2B2 phase results in lower tensile strength.展开更多
The boron content of uranium fuel samples with boron concentrations in the range of 0.05–10 μg/g was determined using inductively coupled plasma optical emission spectrometry(ICP-OES) after the uranium was separated...The boron content of uranium fuel samples with boron concentrations in the range of 0.05–10 μg/g was determined using inductively coupled plasma optical emission spectrometry(ICP-OES) after the uranium was separated by cation exchange. The samples were dissolved in 3 M HNO_3 on a hot plate at 150℃ and evaporated to near dryness. The residues were redissolved in 0.2 M HNO-_3 and passed through a column loaded with Dowex 50WX8-400 resin. Uranium was adsorbed on the resin,while boron was easily eluted with 0.2 M HNO_3. The boron content of the effluent was determined using ICPOES. Several strategies were employed to improve the reliability of the experimentally determined boron content.The addition of mannitol and proper control of the evaporation process were shown to be effective in preventing boron loss during sample dissolution and evaporation. The memory effect was eliminated by flushing the system with 1.5% ammonia for 30 s between successive sample runs,and the matrix match method was used to eliminate the matrix effect arising from mannitol during the ICP-OES analysis. The accuracy of the results of the analysis was determined by addition recovery tests and by comparison with the results of three Chinese certified reference materials(GBW04242, GBW04243, and GBW04232). Using the method we developed, the limit of detection for boron was as low as 0.05 μg/g in uranium fuel samples, and the relative standard deviations for 0.1–0.5 g uranium samples with 0.05–2 μg/g of boron were within 9%.展开更多
Adenosine triphosphate(ATP)borate ester as a new boron agent for boron neutron capture therapy was tested.It was synthesized via a dehydration reaction induced by heating adenosine triphosphate disodium with boric aci...Adenosine triphosphate(ATP)borate ester as a new boron agent for boron neutron capture therapy was tested.It was synthesized via a dehydration reaction induced by heating adenosine triphosphate disodium with boric acid.Next,ATP borate ester pretreatments were assessed to study their effects on cell sensitization from exposure to thermal neutron irradiation emitted by a nuclear reactor.Using cell viability assays(CCK8),survival rates of A549 cells pretreated with or without boroncontaining agents,including ATP borate ester and 4-dihydroxyborylphenylalanine(BPA),were measured.One week after feeding an ATP borate ester solution to tumorbearing nude mice,elemental B content values of tumor muscle and blood were measured using inductively coupled plasma mass spectrometry(ICP-MS).Meanwhile,other tumor tissue samples were placed in a culture medium,subjected to a 3-min neutron irradiation exposure,and then fixed in formalin 24 h later for the terminaldeoxynucleotidyl transferase(TDT)-mediated d UTP nick end labeling(TUNEL)immunohistochemical staining analysis.Results showed that A549 cell irradiation sensitization(irradiation dose of 0.33 Gy)varied with pretreatment.Sensitization values of the ATP borate ester pretreatment group were 1.3–14.1 with boron agent concentrations of 0.3–4.5 mM.Within 1.1–3.4 mM,ATP borate ester showed significantly higher sensitization values than BPA.Meanwhile,TUNEL results demonstrated that apoptosis rates of tumor tissue cells exposed to irradiation after ATP borate ester pretreatment significantly exceeded the corresponding rates for BPA-pretreated cells.In animal experiments,although the distribution ratio of ATP borate ester(tumor tissue/normal muscle,T/N)of 1.2 was not significantly different compared with that of BPA(1.3),the total ATP borate ester concentration in the tumor tissue(0.79±0.05μg/g)significantly exceeded that of BPA(0.58±0.05μg/g).Thus,compared with BPA,the greater enrichment of ATP borate ester in tumor tissues permits preferential targeting toward tumor cells for radiation sensitization.Therefore,ATP borate ester is superior to BPA for use in boron neutron capture therapy.展开更多
The correlation between the effective magnetic anisotropy 〈κ〉 and the temperature T, 〈κ〉-T curve, for the Fe83Nb6B11 alloys as-cast and annealed at 460-580°C was investigated. The experimental results of the 〈...The correlation between the effective magnetic anisotropy 〈κ〉 and the temperature T, 〈κ〉-T curve, for the Fe83Nb6B11 alloys as-cast and annealed at 460-580°C was investigated. The experimental results of the 〈κ〉-T curves for nanocrystalline samples were explained using the theory of exchange interaction between α-Fe grains.展开更多
Purpose: In defining the biological effects of the 10B(n, α)7Li neutron capture reaction, we have proposed a deterministic parsing model (ISHIYAMA-IMAHORI model) to determine the Compound Biological Effectiveness (CB...Purpose: In defining the biological effects of the 10B(n, α)7Li neutron capture reaction, we have proposed a deterministic parsing model (ISHIYAMA-IMAHORI model) to determine the Compound Biological Effectiveness (CBE) factor in Borono-Phenyl-Alanine (BPA)-mediated Boron Neutron Capture Therapy (BNCT). In present paper, we demonstrate a specific method of how the application of the case of application to actual patient data, which is founded on this model for tissues and tumor. Method: To determine the CBE factor, we derived the following new calculation formula founded on the deterministic parsing model with three constants, CBE0, F, n and the eigen value Nth/Nmax.? (1), where, Nth and Nmax are the threshold value of boron concentration of N and saturation boron density and CBE0, F and n are given as 0.5, 8 and 3, respectively. In order to determine Nth and Nmax in the formula, sigmoid logistic function was employed for 10B concentration data, Db(t) obtained by dynamic PET technique. (2), where, A, a and t0 are constants. Results and Conclusion: From the application of sigmoid function to dynamic PET data, it is concluded that the Nth and Nmax for tissue and tumor are identified with the parameter constants in the sigmoid function in Equation (2) as: (3). And the calculated CBE factor values obtained from Equation (1), with Nth/Nmax.展开更多
Boron is the essential microelement for tree growth. Besides growth, blooming, impregnation and seeding are also affected by boron deficiency. This paper discusses the effects of boron on forest growth, including the ...Boron is the essential microelement for tree growth. Besides growth, blooming, impregnation and seeding are also affected by boron deficiency. This paper discusses the effects of boron on forest growth, including the mechanism of boron, visual symptoms of boron deficiency and tree response to boron fertilizer, and provides scientific basis for boron fertilization in forest.展开更多
基金This project was supported by the National Nature Science Foundation of China!(Grant No.59831020 and 59895156)
文摘By using AP-FIM the varity of the ordered degree of Ni_3Al with L1_2 structure with B content was studied. The possibility of boron improving ductility was also discussed from bonding between Ni and Al atoms, and antisite defects in Ni_3Al. The extent of ordering is reduced with an increase in boron content and the autisite defects are most obvious for 0.52at.K B-doped sample that has the best ductility. Some results were verified by X-ray diffraction non. The addition of boron not only influences electron environment at grain boundary but also in the interior of Ni_3Al gm ins, the latter is favorable to improve the ductility of Ni_3Al grains.
基金Shandong Natural Foundation !(Grant No:Z99F01)the Natiotal Natals Science Foundation of China !(Grant NO.59671046).
文摘Several concepts of the grain refinement mechanism of B on hypoeutectic Al-Si alloys have been adopted: the refining effect of B on the a-AI and eutectic Si with the different additions of Al-B master alloys made at 850℃ was investigated; and the Al-B master alloys formed under different temperature conditions have been studied to explore the morphologies of AIB2 particles; slowly cooled sample with addition of Al-B was made to explore the refinement mechanism. AI-B master alloy can refine not only a-AI, but eutectic Si. Theoretical analysis indicates that, although AIB2 does not take part directly in the nucleation process in pure Al in the presence of Si, it provides a substrate for precipitation of a small content of Si from which a-At will grow without any undercooling. When the temperature decreases to eutectic line, AIB2 subsequently nucleates eutectic Si; AIB2 particles appear in two different morphologies, namely, hexagonal platelet and tetradehedron morphology which depend on the processing temperature conditions.
文摘Hydrogenated silicon carbide films (SiC:H) were deposited using the electron cyclotron resonance chemical vapour deposition (ECR-CVD) technique from a mixture of methane, silane and hydrogen, and using diborane and phosphine as doping gases. The effects of changes in the microwave power on the deposition rate and optical bandgap were investigated, and variations in the photoand dark-conductivities and activation energy were studied in conjunction with film analysis using the Raman scattering technique. In the case of boron-doped samples, the conductivity increased rapidly to a maximum, followed by rapid reduction at high microwave power. The ratio of the photo- to dark-conductivity (σph/σd) peaked at microwave power of ~600 W. Under conditions of high microwave power, Raman scattering analysis showed evidence of the formation and increase in the silicon microcrystalline and diamond-like phases in the films, the former of which could account for the rapid increase and the latter the subsequent decrease in the conductivity.In the case of phosphorusdoped SiC:H samples, it was found that increase in the microwave power has the effect of enhancing the formation of the silicon microcrystalline phase in the films which occurred in correspondence to a rapid increase in the conductivity and reduction in the activation energy The conductivity increase stabilised in samples deposited at microwave power exceeding 500 W probably as a result of dopant saturation. Results from Raman scattering measurements also showed that phosphorus doping had the effect of enhancing the formation of the silicon microcrystals in the film whereas the presence of boron had the effect of preserving the amorphous structure.
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Purpose: In defining the biological effects of the 10B(n, α)7Li neutron capture reaction, we have previously developed a deterministic parsing model to determine the Compound Biological Effectiveness (CBE) factor in Borono-Phenyl-Alanine (BPA)-mediated Boron Neutron Capture Therapy (BNCT). In present paper, we demonstrate that the CBE factor is directly and unambiguously derivable by the new formula for any case of intracellular 10Boron (10B) distribution, which is founded on this model for tissues and tumor. Method: To determine the CBE factor, we derive the following new calculation formula founded on the deterministic parsing model with three constants, CBE0, F, n and the eigen value Nth/Nmax. where, Nth and Nmax are the threshold value of boron concentration of N and saturation boron density in tissues and tumor. In order to determine these constants and the eigen values, iterative calculation technique was employed for the CEB factor and Nmax data set previously reported. Results and Conclusion: From the iterative calculation results, it is clear that the calculated CBE factor values obtained are almost identical to the original CBE factors and there is a good correlation between the original CBE factors and Nth/Nmax, when CBE0, F and n are given as 0.5, 8 and 3, respectively. These constants provide a better understanding of different types of intracellular10B distribution.
基金This work was financially supported by the Ministry of Commerce,Industry and Energy of Korea.
文摘The segregation and diffusion of boron during heat treatments were studied. The influence of boron contents, aging time and applied stress on FeMo2B2 formation was also studied. Finally, the effects of boron contents and FeMo2B2 formation on the high temperature strength were studied. Boron atoms were segregated to prior austenite grain boundary during normalizing treatment. And these boron atoms were slowly diffused into the grain interior during tempering and aging at 700 ℃. The FeMo2B2 phase was only formed after 1,000 h aging at 700 ℃ in alloy containing 196 ppm boron. The formation of FeMo2B2 phase is accelerated by the applied stress. It was expected that the formation of FeMo2B2 is closely related to the redistribution of boron atoms. The tensile strengths at 700 ℃ are increased with the increase of boron contents. However, the formation of FeMo2B2 phase results in lower tensile strength.
文摘The boron content of uranium fuel samples with boron concentrations in the range of 0.05–10 μg/g was determined using inductively coupled plasma optical emission spectrometry(ICP-OES) after the uranium was separated by cation exchange. The samples were dissolved in 3 M HNO_3 on a hot plate at 150℃ and evaporated to near dryness. The residues were redissolved in 0.2 M HNO-_3 and passed through a column loaded with Dowex 50WX8-400 resin. Uranium was adsorbed on the resin,while boron was easily eluted with 0.2 M HNO_3. The boron content of the effluent was determined using ICPOES. Several strategies were employed to improve the reliability of the experimentally determined boron content.The addition of mannitol and proper control of the evaporation process were shown to be effective in preventing boron loss during sample dissolution and evaporation. The memory effect was eliminated by flushing the system with 1.5% ammonia for 30 s between successive sample runs,and the matrix match method was used to eliminate the matrix effect arising from mannitol during the ICP-OES analysis. The accuracy of the results of the analysis was determined by addition recovery tests and by comparison with the results of three Chinese certified reference materials(GBW04242, GBW04243, and GBW04232). Using the method we developed, the limit of detection for boron was as low as 0.05 μg/g in uranium fuel samples, and the relative standard deviations for 0.1–0.5 g uranium samples with 0.05–2 μg/g of boron were within 9%.
基金supported by the project,‘‘Research on the targeted treatment of malignant tumors with Base 20180199 New Transmembrane Antibody’’(No.JCYJ20180507182217748)the National Natural Science Foundation of China(No.11375117)
文摘Adenosine triphosphate(ATP)borate ester as a new boron agent for boron neutron capture therapy was tested.It was synthesized via a dehydration reaction induced by heating adenosine triphosphate disodium with boric acid.Next,ATP borate ester pretreatments were assessed to study their effects on cell sensitization from exposure to thermal neutron irradiation emitted by a nuclear reactor.Using cell viability assays(CCK8),survival rates of A549 cells pretreated with or without boroncontaining agents,including ATP borate ester and 4-dihydroxyborylphenylalanine(BPA),were measured.One week after feeding an ATP borate ester solution to tumorbearing nude mice,elemental B content values of tumor muscle and blood were measured using inductively coupled plasma mass spectrometry(ICP-MS).Meanwhile,other tumor tissue samples were placed in a culture medium,subjected to a 3-min neutron irradiation exposure,and then fixed in formalin 24 h later for the terminaldeoxynucleotidyl transferase(TDT)-mediated d UTP nick end labeling(TUNEL)immunohistochemical staining analysis.Results showed that A549 cell irradiation sensitization(irradiation dose of 0.33 Gy)varied with pretreatment.Sensitization values of the ATP borate ester pretreatment group were 1.3–14.1 with boron agent concentrations of 0.3–4.5 mM.Within 1.1–3.4 mM,ATP borate ester showed significantly higher sensitization values than BPA.Meanwhile,TUNEL results demonstrated that apoptosis rates of tumor tissue cells exposed to irradiation after ATP borate ester pretreatment significantly exceeded the corresponding rates for BPA-pretreated cells.In animal experiments,although the distribution ratio of ATP borate ester(tumor tissue/normal muscle,T/N)of 1.2 was not significantly different compared with that of BPA(1.3),the total ATP borate ester concentration in the tumor tissue(0.79±0.05μg/g)significantly exceeded that of BPA(0.58±0.05μg/g).Thus,compared with BPA,the greater enrichment of ATP borate ester in tumor tissues permits preferential targeting toward tumor cells for radiation sensitization.Therefore,ATP borate ester is superior to BPA for use in boron neutron capture therapy.
基金the National Natural Science Foundation of China (Grant No.59871013).
文摘The correlation between the effective magnetic anisotropy 〈κ〉 and the temperature T, 〈κ〉-T curve, for the Fe83Nb6B11 alloys as-cast and annealed at 460-580°C was investigated. The experimental results of the 〈κ〉-T curves for nanocrystalline samples were explained using the theory of exchange interaction between α-Fe grains.
文摘Purpose: In defining the biological effects of the 10B(n, α)7Li neutron capture reaction, we have proposed a deterministic parsing model (ISHIYAMA-IMAHORI model) to determine the Compound Biological Effectiveness (CBE) factor in Borono-Phenyl-Alanine (BPA)-mediated Boron Neutron Capture Therapy (BNCT). In present paper, we demonstrate a specific method of how the application of the case of application to actual patient data, which is founded on this model for tissues and tumor. Method: To determine the CBE factor, we derived the following new calculation formula founded on the deterministic parsing model with three constants, CBE0, F, n and the eigen value Nth/Nmax.? (1), where, Nth and Nmax are the threshold value of boron concentration of N and saturation boron density and CBE0, F and n are given as 0.5, 8 and 3, respectively. In order to determine Nth and Nmax in the formula, sigmoid logistic function was employed for 10B concentration data, Db(t) obtained by dynamic PET technique. (2), where, A, a and t0 are constants. Results and Conclusion: From the application of sigmoid function to dynamic PET data, it is concluded that the Nth and Nmax for tissue and tumor are identified with the parameter constants in the sigmoid function in Equation (2) as: (3). And the calculated CBE factor values obtained from Equation (1), with Nth/Nmax.
文摘Boron is the essential microelement for tree growth. Besides growth, blooming, impregnation and seeding are also affected by boron deficiency. This paper discusses the effects of boron on forest growth, including the mechanism of boron, visual symptoms of boron deficiency and tree response to boron fertilizer, and provides scientific basis for boron fertilization in forest.
