High purity magnesium is not only an important basic raw material for semiconductor and electronics industries,but also a promising new generation of electrochemical energy storage materials and biomedical materials.I...High purity magnesium is not only an important basic raw material for semiconductor and electronics industries,but also a promising new generation of electrochemical energy storage materials and biomedical materials.Impurities in high-purity magnesium affect material properties,which has become the most critical factor restricting its application.However,accurate analysis of multiple ultra-trace impurity elements in high-purity magnesium is extremely challenging.In this paper,based on the synergistic effect of N_(2)O/H_(2) reaction gas mixture to eliminate spectral interference of inductively coupled plasma tandem mass spectrometry(ICP-MS/MS),a new strategy for the quantification of 45 ultra-trace impurity elements in high-purity magnesium was proposed.The results indicated that the limits of detection(LOD)were in the range of 0.02–18.5 ng L^(−1);the LODs of the challenging non-metallic elements Si and S were 18.5 and 12.2 ng L^(−1),respectively;and the LODs of all the other analytes were less than 10 ng L^(−1).Even under hot plasma conditions,LODs of alkali metal elements were also less than 5 ng L^(−1).The spike recovery of each analyte was 93.6%–107%,and the relative standard deviation(RSD)was 3.2%–6.9%,respectively.At a 95%level of confidence,no significant differences were found between the results obtained under the optimal conditions for the analyte with the developed method and the measurement results of SF-ICP-MS.The developed method indicated low LOD,high sample throughput,and complete interference elimination,demonstrating a new avenue for the rapid determination of ultra-trace elements in high-purity magnesium.展开更多
The process mineralogy of kaolin associated quartz flotation concentrate was studied.The experimental results show that the content of SiO2 in the flotation concentrate is 99.66%,and the main impurity elements in the ...The process mineralogy of kaolin associated quartz flotation concentrate was studied.The experimental results show that the content of SiO2 in the flotation concentrate is 99.66%,and the main impurity elements in the concentrate are Al,Fe,K,and Na.The gangue minerals in the flotation concentrate are mainly mica and feldspar symbiosis with quartz in the form of connexion or mineral inclusion.By taking the flotation concentrate as the raw material,the experimental research on HF concentration,HCl concentration,HNO3 concentration,acid leaching temperature,acid leaching time,and the leaching liquid solid ratio of hot pressing acid leaching conditions was carried out.Finally,the factors affecting the quality of purified products were analyzed.Through the acid leaching experiment,it can be seen that hydrofluoric acid has a greater effect on Al and Fe elements,hydrochloric acid has a greater effect on Fe elements,and nitric acid concentration has a smaller effect on impurity elements(which can also be confirmed from the thermodynamic analysis);the acid leaching temperature,the acid leaching time,and the leaching liquid solid mass ratio are proportional to the acid leaching effect.The Al content decreases from 1304.73 to 214.10μg/g,and the aluminum removal rate is 86.12%.The Fe content decreases from 39.35 to 3.72μg/g,and the iron removal rate is 90.55%.Thermodynamic and kinetic studies show that at 220℃,the chemical reaction between quartz and gangue minerals and the leaching agent can be spontaneous in the direction of positive reaction,and gangue minerals and the leaching agent had priority reaction.The mixed acid leaching process accords with the diffusion control model,Ea is 15.16 kJ/mol,which can provide a theoretical guidance for the purification of quartz.展开更多
Modifying effect and mechanism of trace rare earth on Fe(Si) rich impurity phases in commercial purity aluminum were studied with the aids of SEM, EDAX, TEM, etc. It is found that Ce rich mixed rare earth (RE) is an...Modifying effect and mechanism of trace rare earth on Fe(Si) rich impurity phases in commercial purity aluminum were studied with the aids of SEM, EDAX, TEM, etc. It is found that Ce rich mixed rare earth (RE) is an effective modifying agent, which makes the coarse Fe rich impurity phases transform into complex compounds of tiny, sphere/short stick form, thus improving mechanical properties of this material; its modifying mechanism is in that RE gathering in front of solid/liquid interface enters into the impurity phases, forming complex (AlFeSiRE) compounds; or is adsorbed in the impurity phases surface, impeding the growth of impurity phases; however, excessive RE will result in the increasing of RE compounds (secondary phases), and plasticity reduction of this material. Therefore, its addition amount should be less than 0 07% (mass fraction).展开更多
The effect of forging passes on the refinement of high purity aluminum during multi-forging was investigated. The attention was focused on the structure uniformity due to deformation uniformity and the grain refinemen...The effect of forging passes on the refinement of high purity aluminum during multi-forging was investigated. The attention was focused on the structure uniformity due to deformation uniformity and the grain refinement limitation with very high strains. The results show that the fine grain zone in the center of sample expands gradually with the increase of forging passes. When the forging passes reach 6, an X-shape fine grain zone is initially formed. With a further increase of the passes, this X-shape zone tends to spread the whole sample. Limitation in the structural refinement is observed with increasing strains during multi-forging process at the room temperature. The grains size in the center is refined to a certain size （110 μm as forging passes reach 12, and there is no further grain refinement in the center with increasing the forging passes to 24. However, the size of the coarse grains near the surface is continuously decreased with increasing the forging passes to 24.展开更多
A novel type nano TiN/Ti composite grain refiner （TiN/Ti refiner） was prepared by high energy ball milling, and its effect on as-cast and hot-working microstructure of commercial purity aluminum （pure Al） was inve...A novel type nano TiN/Ti composite grain refiner （TiN/Ti refiner） was prepared by high energy ball milling, and its effect on as-cast and hot-working microstructure of commercial purity aluminum （pure Al） was investigated. The results show that TiN/Ti refiner exhibits excellent grain refining performances on pure Al. With an addition of 0.2% TiN/Ti refiner, the average grain size of pure Al decreases to 82 μm, which is smaller than that of pure Ti and Al 5Ti 1B master alloy as refiners. The microstructure of weld joint of pure Al with 0.1% TiN/Ti refiner is fine equiaxed grains and the hardness of weld joint is higher than that of the base metal. For pure Al with 40% cold deformation and recrystallization at 250 °C for 1.0 h, the grains of the sample added 0.1% Ti powder have an obvious grain growth behavior. In contrast, oriented grains caused by deformation have been eliminated, and there is no obvious grain growth in pure Al refined with 0.1% TiN/Ti refiner, indicating that nano TiN in the refiner inhibits the growth of grain during recrystallization.展开更多
Signal to noise ratio （SNR） and resolution are two important but contradictory characteristics used to evaluate the quality of seismic data. For relatively preserving SNR while enhancing resolution, the signal purit...Signal to noise ratio （SNR） and resolution are two important but contradictory characteristics used to evaluate the quality of seismic data. For relatively preserving SNR while enhancing resolution, the signal purity spectrum is introduced, estimated, and used to define the desired output amplitude spectrum after deconvolution. Since a real reflectivity series is blue rather than white, the effects of white reflectivity hypothesis on wavelets are experimentally analyzed and color compensation is applied after spectrum whitening. Experiments on real seismic data indicate that the cascade of the two processing stages can improve the ability of seismic data to delineate the geological details.展开更多
[Objective] This study aimed to screen a set of SSR core primers suitable for purity identification of pepper （Capsicum） hybrids. [Method] DNA fingerprint of 100 pepper hybrids was analyzed using 17 SSR primers. [Re...[Objective] This study aimed to screen a set of SSR core primers suitable for purity identification of pepper （Capsicum） hybrids. [Method] DNA fingerprint of 100 pepper hybrids was analyzed using 17 SSR primers. [Result] According to the polymorphism and heterozygosity, Hpms1-214, Es395 and Hpmsl-5 were determined as three preferred core primers for purity identification of pepper hybrids. By using these three preferred core primers, 97 pepper hybrids （accounting for 97%） had heterozygous band pattern with at least one primer. Es330, Es363, Epms923, Es120 and Es64 were determined as candidate core primers for purity identification of pepper hybrids. Specific primers of 14 varieties were obtained, which could be used to further screen parent-complementary primers of each pepper hybrid. [Con- clusion] This study laid the foundation for constructing standard DNA fingerprints for purity identification of pepper hybrids.展开更多
Objective] This study was conducted to verify the feasibiIity of ISSR marker for identifying genetic purity of bitter gourd hybrid, and thus to provide an effective method for seed purity test in production practices....Objective] This study was conducted to verify the feasibiIity of ISSR marker for identifying genetic purity of bitter gourd hybrid, and thus to provide an effective method for seed purity test in production practices. [Method] The DNA fin-gerprints of a bitter gourd cuItivar Xiuyu 1 and its parents were analyzed using IS-SR marker with 91 primers. [Result] Two primers ISSR-845 and ISSR-891 which ampIified two DNA bands of 510 and 300 bp respectiveIy from F1 generation and its parents were screened out from 91 primers. ISSR-845 couId distinguish the male parent from F1 hybrid and the female parent, whiIe ISSR-891 couId distinguish the female parent inbred Iine from Xiuyu 1. Seed purity test with the specific markers gave the same resuIt with fiIed trials based on morphoIogical identification. [Conclu-sion] ISSR marker is an accurate, simpIe and effective method for seed purity test bitter gourd hybrid, and thus can be used in production practices.展开更多
[Objective] The aim was to establish more specific, sensitive, accurate and practical method to detect purity of Thai Hom Mali rice. [Method] RAPD method cooperated with two primers of KDML105 and RD15 was established...[Objective] The aim was to establish more specific, sensitive, accurate and practical method to detect purity of Thai Hom Mali rice. [Method] RAPD method cooperated with two primers of KDML105 and RD15 was established by feeling for the extraction methods of DNA, optimizing concentrations of the factors influencing the results of RAPD such as template DNA, Mg2＋, random primer, dNTPs and Taq polymerase, and screening the random primers. [Result] The optimum RAPD reaction system was 25.0 μl in total volume, containing 4.0-32.0 ng/μl of template DNA, 200.0 μg/L random primer, 2.0 mmol/L Mg2＋, 200.0 μmol/L dNTPs and 1.0 U of Taq enzyme. Then, the Thai Hom Mali rice and non-Thai Hom Mali rice can be distinguished according to the presence or absence of two DNA markers. [Conclusion] The RAPD technology can effectively cover the shortages of identifications by sense and boiling in water; in addition, it is simple, sensitive and low-cost, suitable to be used in routine tests.展开更多
An integer-N frequency synthesizer in 0.35μm SiGe BiCMOS is presented. By implementing different building blocks with different types of devices,a high purity frequency synthesizer with excellent spur and phase noise...An integer-N frequency synthesizer in 0.35μm SiGe BiCMOS is presented. By implementing different building blocks with different types of devices,a high purity frequency synthesizer with excellent spur and phase noise performance has been realized. All the building blocks are implemented with differential topology except for the off-chip loop filter. To further reduce the phase noise,bonding wires are used to form the resonator in the LC-VCO. The frequency synthesizer operates from 2.39 to 2.72GHz with output power of about 0dBm. The measured closed-loop phase noise is - 95dBc/Hz at 100kHz offset and - 116dBc/Hz at 1MHz offset from the carrier. The power level of the reference spur is less than - 72dBc. With a 3V power supply, the whole chip including the output buffers consumes 60mA.展开更多
[Objective] SSR molecular marker technique was used to determine the purity of sunflower seed with the aim to provide accurate, convenient method for the identification of the purity of hybrid seeds in production and ...[Objective] SSR molecular marker technique was used to determine the purity of sunflower seed with the aim to provide accurate, convenient method for the identification of the purity of hybrid seeds in production and processing. [Method] With the DNA of Xinshikui 6 and its parents as template, about 100 pairs of SSR molecular markers were screened after DNA extraction, PCR amplification and electrophoresis production. [Results] SSR polymorphic primer marker 532 produced a specific band of 469 bp in the female parent, and a specific band of 451 bp in the male parent; primer marker 574 produced a specific band of 364 bp in the female parent, and a specific band of 384 bp in the male parent. The indoor molecular purity identification and field purity identification were consistent with each other. The primer marker 532 and 574 could be obtained from the SSR molecular marker method to distinguish the male parent, female parent and hybrid of Xinshikui 6, and both of the 2 primer markers can effectively identify the purities of the hybrid seeds of Xinshikui 6, as well as the authenticity of the seeds. [Conclusion] The proposed method was simple, fast, accurate to operate with the advantages of high reproducibility, and it had become the major method in the identification of sunflower varieties.展开更多
A method was developed for the simultaneous determination of seven trace impurities (Cd, Mn, Pb, Zn, Cu, Fe and Ni) in high purity cobalt oxide by ICP AES. The matrix effect was eliminated by preci pitation with 1 nit...A method was developed for the simultaneous determination of seven trace impurities (Cd, Mn, Pb, Zn, Cu, Fe and Ni) in high purity cobalt oxide by ICP AES. The matrix effect was eliminated by preci pitation with 1 nitroso 2 naphthol. The matrix effect of cobalt on the absorptions of trace impurities, the effects of reaction time, pH value, dosage of precipitant on the formation of cobalt 1 nitroso 2 naphthol complex, the effects of hydrochloric acid on the stability of this complex and masking of elements were studied. Recoveries of the impurities in spiked sample are from 90% to 110% with a precision of 1.1% 5.0% RSD. The detection limits of the seven elements are in the range of 0.01 0.24μg/g. The method can be applied to the analysis of high purity cobalt metal, cobalt oxide and other cobalt compounds.展开更多
Hardness of materials depends significantly on the indentation size and grain/sub-grain size via microindentation and nanoindentation tests of high-purity tungsten with different structures.The grain boundary effect a...Hardness of materials depends significantly on the indentation size and grain/sub-grain size via microindentation and nanoindentation tests of high-purity tungsten with different structures.The grain boundary effect and indentation size effect were explored.The indentation hardness was fitted using the Nix-Gao model by considering the scaling factor.The results show that the scaling factor is barely correlated with the grain/sub-grain size.The interaction between the plastically deformed zone（PDZ） boundary and the grain/sub-grain boundary is believed to be the reason that leads to an increase of the measured hardness at the specific depths.Results also indicate that the area of the PDZ is barely correlated with the grain/sub-grain size,and the indentation hardness starts to stabilize once the PDZ expands to the dimension of an individual grain/sub-grain.展开更多
High purity silicon carbide （SIC） powder was synthesized in-situ by chemical reaction between silicon and carbon powder. In order to ensure that the impurity concentration of the resulting SiC powder is suitable for...High purity silicon carbide （SIC） powder was synthesized in-situ by chemical reaction between silicon and carbon powder. In order to ensure that the impurity concentration of the resulting SiC powder is suitable for high-resistivity SiC single crystal growth, the preparation technology of SiC powder is different from that of SiC ceramic. The influence of the shape and size of carbon particles on the morphology and phase composition of the obtained SiC powder were discussed. The phase composition and morphology of the products were investigated by X-ray diffraction, Raman microspectroscopy and scanning electron microscopy. The results show that the composition of resulting SiC by in-situ synthesis from Si/C mixture strongly depends on the nature of the carbon source, which corresponds to the particle size and shape, as well as the preparation temperature. In the experimental conditions, flake graphite is more suitable for the synthesis of SiC powder than activated carbon because of its relatively smaller particle size and flake shape, which make the conversion more complete. The major phase composition of the full conversion products is β-SiC, with traces of α-SiC. Glow discharge mass spectroscopy measurements indicated that SiC powder synthesized with this chemical reaction method can meet the purity demand for the growth of high-resistivity SiC single crystals.展开更多
A An analytical method using high resolution inductively coupled plasma mass spectrometry （HR-ICP-MS） for rapid simultaneous determination of 24 elements （Be, Mg, A1, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, Ga, Ge, As, Se, ...A An analytical method using high resolution inductively coupled plasma mass spectrometry （HR-ICP-MS） for rapid simultaneous determination of 24 elements （Be, Mg, A1, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, Ga, Ge, As, Se, Mo, Ag, Cd, Sn Sb, Ba, Pt, Au, and Pb） in high purity cobalt was described. Sample digestions were performed in closed microwave vessels using HNO3 and HCI. The matrix effects because of the presence of excess HCI and Co were evaluated. The usefulness of high mass resolution for overcoming some spectral interference was demonstrated. The optimum conditions for the determination were tested and discussed. The standard addition method was employed for quantitative analysis. The detection limits were 0.016-1.50 ].tg·g^-1, the recovery ratios were 92.2%-111.2%, and the RSD was less than 3.6%. The method was accurate, quick, and convenient. It was applied to the determination of trace impurities in high purity cobalt with satisfactory results.展开更多
The contents ofMg, Al, Si, Ti, Cr, Mn, Fe, Co, Cu, Ga, As, Se, Cd, Sb, Pb and Bi in high purity nickel were determined by high resolution inductively coupled plasma mass spectrometry （HR-ICP-MS）. The sample was diss...The contents ofMg, Al, Si, Ti, Cr, Mn, Fe, Co, Cu, Ga, As, Se, Cd, Sb, Pb and Bi in high purity nickel were determined by high resolution inductively coupled plasma mass spectrometry （HR-ICP-MS）. The sample was dissolved in HNO3 and HCI by microwave digestion. Most of the spectral interferences could be avoided by measuring in the high resolution mode. The matrix effects because of the presence of excess HC1 and nickel were evaluated. Correction for matrix effects was made using Sc, Rh and T1 as internal standards. The optimum conditions for the determination were tested and discussed. The detection limits range from 0.012 to 1.76 ~tg/g depending on the type of elements. The applicability of the proposed method is also validated by the analysis of high purity nickel reference material （NIST SRM 671）. The relative standard deviation （RSD） is less than 3.3%. Results for determination of trace elements in high purity nickel were presented.展开更多
Five super hybrid rice combinations, i.e. HYS-1/R105, Pei'ai 64S/E32, Liangyoupeijiu (Pei'ai 64S/9311), 88S/0293, and J23A/Q611, and their parental lines were tested by means of SSR analysis. A total of 144 SS...Five super hybrid rice combinations, i.e. HYS-1/R105, Pei'ai 64S/E32, Liangyoupeijiu (Pei'ai 64S/9311), 88S/0293, and J23A/Q611, and their parental lines were tested by means of SSR analysis. A total of 144 SSR primer pairs distributed on 12 rice chromosomes were used, out of which 47 detected polymorphism among the tested rice lines. Among all these primers, RM337 and RM154 produced polymorphic patterns in four or more of the tested experimental materials respectively, and they could distinguish among most rice genotypes tested. Twenty-four primer pairs, two on each rice chromosome, were selected to make a reference SSR marker-based fingerprinting for the rice lines. For most of the primer pairs, F1 hybrids mainly showed complementary pattern of both parents, which could be very useful to distinguish the F1 from its parental lines. In addition, 5 primer pairs were selected as special primer pairs for five hybrid rice combinations respectively. By combining the rapid, simple method on DNA extraction, it is suggested that SSR technique has wide prospective in variety authentication and purity identification.展开更多
TiClx （x=2.17） was prepared by using titanium sponge to reduce the concentration of TiCl4 in a NaCl-KCl melt under negative pressure. The as-prepared NaCl-KCl-TiClx melt was employed as the electrolyte, and two para...TiClx （x=2.17） was prepared by using titanium sponge to reduce the concentration of TiCl4 in a NaCl-KCl melt under negative pressure. The as-prepared NaCl-KCl-TiClx melt was employed as the electrolyte, and two parallel crude titanium plates and one high-purity titanium plate were used as the anode and cathode, respectively. A series of electrochemical tests were performed to investigate the influence of electrolytic parameters on the current efficiency and quality of cathodic products. The results indicated that the quality of cathodic products was related to the current efficiency, which is significantly dependent on the current density and the initial concentration of titanium ions. The significance of this study is the attainment of high-purity titanium with a low oxygen content of 30× 10^-6.展开更多
基金supported by the Natural Science Foundation of China(52171103 and 21975289).
文摘High purity magnesium is not only an important basic raw material for semiconductor and electronics industries,but also a promising new generation of electrochemical energy storage materials and biomedical materials.Impurities in high-purity magnesium affect material properties,which has become the most critical factor restricting its application.However,accurate analysis of multiple ultra-trace impurity elements in high-purity magnesium is extremely challenging.In this paper,based on the synergistic effect of N_(2)O/H_(2) reaction gas mixture to eliminate spectral interference of inductively coupled plasma tandem mass spectrometry(ICP-MS/MS),a new strategy for the quantification of 45 ultra-trace impurity elements in high-purity magnesium was proposed.The results indicated that the limits of detection(LOD)were in the range of 0.02–18.5 ng L^(−1);the LODs of the challenging non-metallic elements Si and S were 18.5 and 12.2 ng L^(−1),respectively;and the LODs of all the other analytes were less than 10 ng L^(−1).Even under hot plasma conditions,LODs of alkali metal elements were also less than 5 ng L^(−1).The spike recovery of each analyte was 93.6%–107%,and the relative standard deviation(RSD)was 3.2%–6.9%,respectively.At a 95%level of confidence,no significant differences were found between the results obtained under the optimal conditions for the analyte with the developed method and the measurement results of SF-ICP-MS.The developed method indicated low LOD,high sample throughput,and complete interference elimination,demonstrating a new avenue for the rapid determination of ultra-trace elements in high-purity magnesium.
文摘The process mineralogy of kaolin associated quartz flotation concentrate was studied.The experimental results show that the content of SiO2 in the flotation concentrate is 99.66%,and the main impurity elements in the concentrate are Al,Fe,K,and Na.The gangue minerals in the flotation concentrate are mainly mica and feldspar symbiosis with quartz in the form of connexion or mineral inclusion.By taking the flotation concentrate as the raw material,the experimental research on HF concentration,HCl concentration,HNO3 concentration,acid leaching temperature,acid leaching time,and the leaching liquid solid ratio of hot pressing acid leaching conditions was carried out.Finally,the factors affecting the quality of purified products were analyzed.Through the acid leaching experiment,it can be seen that hydrofluoric acid has a greater effect on Al and Fe elements,hydrochloric acid has a greater effect on Fe elements,and nitric acid concentration has a smaller effect on impurity elements(which can also be confirmed from the thermodynamic analysis);the acid leaching temperature,the acid leaching time,and the leaching liquid solid mass ratio are proportional to the acid leaching effect.The Al content decreases from 1304.73 to 214.10μg/g,and the aluminum removal rate is 86.12%.The Fe content decreases from 39.35 to 3.72μg/g,and the iron removal rate is 90.55%.Thermodynamic and kinetic studies show that at 220℃,the chemical reaction between quartz and gangue minerals and the leaching agent can be spontaneous in the direction of positive reaction,and gangue minerals and the leaching agent had priority reaction.The mixed acid leaching process accords with the diffusion control model,Ea is 15.16 kJ/mol,which can provide a theoretical guidance for the purification of quartz.
文摘Modifying effect and mechanism of trace rare earth on Fe(Si) rich impurity phases in commercial purity aluminum were studied with the aids of SEM, EDAX, TEM, etc. It is found that Ce rich mixed rare earth (RE) is an effective modifying agent, which makes the coarse Fe rich impurity phases transform into complex compounds of tiny, sphere/short stick form, thus improving mechanical properties of this material; its modifying mechanism is in that RE gathering in front of solid/liquid interface enters into the impurity phases, forming complex (AlFeSiRE) compounds; or is adsorbed in the impurity phases surface, impeding the growth of impurity phases; however, excessive RE will result in the increasing of RE compounds (secondary phases), and plasticity reduction of this material. Therefore, its addition amount should be less than 0 07% (mass fraction).
基金Projects(51204053,51074048,51204048)supported by the National Natural Science Foundation of ChinaProject(20110491518)supported by China Postdoctoral Science FoundationProject(2012CB619506)supported by the National Basic Research Program of China
文摘The effect of forging passes on the refinement of high purity aluminum during multi-forging was investigated. The attention was focused on the structure uniformity due to deformation uniformity and the grain refinement limitation with very high strains. The results show that the fine grain zone in the center of sample expands gradually with the increase of forging passes. When the forging passes reach 6, an X-shape fine grain zone is initially formed. With a further increase of the passes, this X-shape zone tends to spread the whole sample. Limitation in the structural refinement is observed with increasing strains during multi-forging process at the room temperature. The grains size in the center is refined to a certain size （110 μm as forging passes reach 12, and there is no further grain refinement in the center with increasing the forging passes to 24. However, the size of the coarse grains near the surface is continuously decreased with increasing the forging passes to 24.
文摘A novel type nano TiN/Ti composite grain refiner （TiN/Ti refiner） was prepared by high energy ball milling, and its effect on as-cast and hot-working microstructure of commercial purity aluminum （pure Al） was investigated. The results show that TiN/Ti refiner exhibits excellent grain refining performances on pure Al. With an addition of 0.2% TiN/Ti refiner, the average grain size of pure Al decreases to 82 μm, which is smaller than that of pure Ti and Al 5Ti 1B master alloy as refiners. The microstructure of weld joint of pure Al with 0.1% TiN/Ti refiner is fine equiaxed grains and the hardness of weld joint is higher than that of the base metal. For pure Al with 40% cold deformation and recrystallization at 250 °C for 1.0 h, the grains of the sample added 0.1% Ti powder have an obvious grain growth behavior. In contrast, oriented grains caused by deformation have been eliminated, and there is no obvious grain growth in pure Al refined with 0.1% TiN/Ti refiner, indicating that nano TiN in the refiner inhibits the growth of grain during recrystallization.
基金supported by the National Natural Science Foundation of China(Grant No.41174117)PetroChina Innovation Foundation(Grant No.2010D-5006-0301)
文摘Signal to noise ratio （SNR） and resolution are two important but contradictory characteristics used to evaluate the quality of seismic data. For relatively preserving SNR while enhancing resolution, the signal purity spectrum is introduced, estimated, and used to define the desired output amplitude spectrum after deconvolution. Since a real reflectivity series is blue rather than white, the effects of white reflectivity hypothesis on wavelets are experimentally analyzed and color compensation is applied after spectrum whitening. Experiments on real seismic data indicate that the cascade of the two processing stages can improve the ability of seismic data to delineate the geological details.
基金Supported by Excellent Team Training Program of Yunnan Academy of Agriculture Sciences(YAAS2014YY002)~~
文摘[Objective] This study aimed to screen a set of SSR core primers suitable for purity identification of pepper （Capsicum） hybrids. [Method] DNA fingerprint of 100 pepper hybrids was analyzed using 17 SSR primers. [Result] According to the polymorphism and heterozygosity, Hpms1-214, Es395 and Hpmsl-5 were determined as three preferred core primers for purity identification of pepper hybrids. By using these three preferred core primers, 97 pepper hybrids （accounting for 97%） had heterozygous band pattern with at least one primer. Es330, Es363, Epms923, Es120 and Es64 were determined as candidate core primers for purity identification of pepper hybrids. Specific primers of 14 varieties were obtained, which could be used to further screen parent-complementary primers of each pepper hybrid. [Con- clusion] This study laid the foundation for constructing standard DNA fingerprints for purity identification of pepper hybrids.
基金Supported by Key Technology Research and Development Program for Agriculture of Jianngsu Province(BE2012323)~~
文摘Objective] This study was conducted to verify the feasibiIity of ISSR marker for identifying genetic purity of bitter gourd hybrid, and thus to provide an effective method for seed purity test in production practices. [Method] The DNA fin-gerprints of a bitter gourd cuItivar Xiuyu 1 and its parents were analyzed using IS-SR marker with 91 primers. [Result] Two primers ISSR-845 and ISSR-891 which ampIified two DNA bands of 510 and 300 bp respectiveIy from F1 generation and its parents were screened out from 91 primers. ISSR-845 couId distinguish the male parent from F1 hybrid and the female parent, whiIe ISSR-891 couId distinguish the female parent inbred Iine from Xiuyu 1. Seed purity test with the specific markers gave the same resuIt with fiIed trials based on morphoIogical identification. [Conclu-sion] ISSR marker is an accurate, simpIe and effective method for seed purity test bitter gourd hybrid, and thus can be used in production practices.
文摘[Objective] The aim was to establish more specific, sensitive, accurate and practical method to detect purity of Thai Hom Mali rice. [Method] RAPD method cooperated with two primers of KDML105 and RD15 was established by feeling for the extraction methods of DNA, optimizing concentrations of the factors influencing the results of RAPD such as template DNA, Mg2＋, random primer, dNTPs and Taq polymerase, and screening the random primers. [Result] The optimum RAPD reaction system was 25.0 μl in total volume, containing 4.0-32.0 ng/μl of template DNA, 200.0 μg/L random primer, 2.0 mmol/L Mg2＋, 200.0 μmol/L dNTPs and 1.0 U of Taq enzyme. Then, the Thai Hom Mali rice and non-Thai Hom Mali rice can be distinguished according to the presence or absence of two DNA markers. [Conclusion] The RAPD technology can effectively cover the shortages of identifications by sense and boiling in water; in addition, it is simple, sensitive and low-cost, suitable to be used in routine tests.
文摘An integer-N frequency synthesizer in 0.35μm SiGe BiCMOS is presented. By implementing different building blocks with different types of devices,a high purity frequency synthesizer with excellent spur and phase noise performance has been realized. All the building blocks are implemented with differential topology except for the off-chip loop filter. To further reduce the phase noise,bonding wires are used to form the resonator in the LC-VCO. The frequency synthesizer operates from 2.39 to 2.72GHz with output power of about 0dBm. The measured closed-loop phase noise is - 95dBc/Hz at 100kHz offset and - 116dBc/Hz at 1MHz offset from the carrier. The power level of the reference spur is less than - 72dBc. With a 3V power supply, the whole chip including the output buffers consumes 60mA.
基金Supported by the Key Science and Technology Project of Xinjiang Production and Construction Corps(2016AC024)the Key Science and Technology Project for Seed Breeding during the Thirteenth Five Year Plan of Xinjiang Production and Construction Corps(2014BA005)+1 种基金the China Agriculture Research System for Sunflower of China(CARS-16)the Science and Technology Project for Supporting Xinjiang of China(2014AB007)~~
文摘[Objective] SSR molecular marker technique was used to determine the purity of sunflower seed with the aim to provide accurate, convenient method for the identification of the purity of hybrid seeds in production and processing. [Method] With the DNA of Xinshikui 6 and its parents as template, about 100 pairs of SSR molecular markers were screened after DNA extraction, PCR amplification and electrophoresis production. [Results] SSR polymorphic primer marker 532 produced a specific band of 469 bp in the female parent, and a specific band of 451 bp in the male parent; primer marker 574 produced a specific band of 364 bp in the female parent, and a specific band of 384 bp in the male parent. The indoor molecular purity identification and field purity identification were consistent with each other. The primer marker 532 and 574 could be obtained from the SSR molecular marker method to distinguish the male parent, female parent and hybrid of Xinshikui 6, and both of the 2 primer markers can effectively identify the purities of the hybrid seeds of Xinshikui 6, as well as the authenticity of the seeds. [Conclusion] The proposed method was simple, fast, accurate to operate with the advantages of high reproducibility, and it had become the major method in the identification of sunflower varieties.
文摘A method was developed for the simultaneous determination of seven trace impurities (Cd, Mn, Pb, Zn, Cu, Fe and Ni) in high purity cobalt oxide by ICP AES. The matrix effect was eliminated by preci pitation with 1 nitroso 2 naphthol. The matrix effect of cobalt on the absorptions of trace impurities, the effects of reaction time, pH value, dosage of precipitant on the formation of cobalt 1 nitroso 2 naphthol complex, the effects of hydrochloric acid on the stability of this complex and masking of elements were studied. Recoveries of the impurities in spiked sample are from 90% to 110% with a precision of 1.1% 5.0% RSD. The detection limits of the seven elements are in the range of 0.01 0.24μg/g. The method can be applied to the analysis of high purity cobalt metal, cobalt oxide and other cobalt compounds.
基金Project(51174235)supported by the National Natural Science Foundation of China
文摘Hardness of materials depends significantly on the indentation size and grain/sub-grain size via microindentation and nanoindentation tests of high-purity tungsten with different structures.The grain boundary effect and indentation size effect were explored.The indentation hardness was fitted using the Nix-Gao model by considering the scaling factor.The results show that the scaling factor is barely correlated with the grain/sub-grain size.The interaction between the plastically deformed zone（PDZ） boundary and the grain/sub-grain boundary is believed to be the reason that leads to an increase of the measured hardness at the specific depths.Results also indicate that the area of the PDZ is barely correlated with the grain/sub-grain size,and the indentation hardness starts to stabilize once the PDZ expands to the dimension of an individual grain/sub-grain.
文摘High purity silicon carbide （SIC） powder was synthesized in-situ by chemical reaction between silicon and carbon powder. In order to ensure that the impurity concentration of the resulting SiC powder is suitable for high-resistivity SiC single crystal growth, the preparation technology of SiC powder is different from that of SiC ceramic. The influence of the shape and size of carbon particles on the morphology and phase composition of the obtained SiC powder were discussed. The phase composition and morphology of the products were investigated by X-ray diffraction, Raman microspectroscopy and scanning electron microscopy. The results show that the composition of resulting SiC by in-situ synthesis from Si/C mixture strongly depends on the nature of the carbon source, which corresponds to the particle size and shape, as well as the preparation temperature. In the experimental conditions, flake graphite is more suitable for the synthesis of SiC powder than activated carbon because of its relatively smaller particle size and flake shape, which make the conversion more complete. The major phase composition of the full conversion products is β-SiC, with traces of α-SiC. Glow discharge mass spectroscopy measurements indicated that SiC powder synthesized with this chemical reaction method can meet the purity demand for the growth of high-resistivity SiC single crystals.
基金the Natural Science Foundation of Hunan Province, China (No. 05JJ40017).
文摘A An analytical method using high resolution inductively coupled plasma mass spectrometry （HR-ICP-MS） for rapid simultaneous determination of 24 elements （Be, Mg, A1, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, Ga, Ge, As, Se, Mo, Ag, Cd, Sn Sb, Ba, Pt, Au, and Pb） in high purity cobalt was described. Sample digestions were performed in closed microwave vessels using HNO3 and HCI. The matrix effects because of the presence of excess HCI and Co were evaluated. The usefulness of high mass resolution for overcoming some spectral interference was demonstrated. The optimum conditions for the determination were tested and discussed. The standard addition method was employed for quantitative analysis. The detection limits were 0.016-1.50 ].tg·g^-1, the recovery ratios were 92.2%-111.2%, and the RSD was less than 3.6%. The method was accurate, quick, and convenient. It was applied to the determination of trace impurities in high purity cobalt with satisfactory results.
基金Project(21075138) supported by the National Natural Science Foundation of ChinaProject(cstc2011jjA0780) supported by Natural Science Foundation of Chongqing City,ChinaProject(KJ121311) supported by Educational Commission of Chongqing City of China
文摘The contents ofMg, Al, Si, Ti, Cr, Mn, Fe, Co, Cu, Ga, As, Se, Cd, Sb, Pb and Bi in high purity nickel were determined by high resolution inductively coupled plasma mass spectrometry （HR-ICP-MS）. The sample was dissolved in HNO3 and HCI by microwave digestion. Most of the spectral interferences could be avoided by measuring in the high resolution mode. The matrix effects because of the presence of excess HC1 and nickel were evaluated. Correction for matrix effects was made using Sc, Rh and T1 as internal standards. The optimum conditions for the determination were tested and discussed. The detection limits range from 0.012 to 1.76 ~tg/g depending on the type of elements. The applicability of the proposed method is also validated by the analysis of high purity nickel reference material （NIST SRM 671）. The relative standard deviation （RSD） is less than 3.3%. Results for determination of trace elements in high purity nickel were presented.
文摘Five super hybrid rice combinations, i.e. HYS-1/R105, Pei'ai 64S/E32, Liangyoupeijiu (Pei'ai 64S/9311), 88S/0293, and J23A/Q611, and their parental lines were tested by means of SSR analysis. A total of 144 SSR primer pairs distributed on 12 rice chromosomes were used, out of which 47 detected polymorphism among the tested rice lines. Among all these primers, RM337 and RM154 produced polymorphic patterns in four or more of the tested experimental materials respectively, and they could distinguish among most rice genotypes tested. Twenty-four primer pairs, two on each rice chromosome, were selected to make a reference SSR marker-based fingerprinting for the rice lines. For most of the primer pairs, F1 hybrids mainly showed complementary pattern of both parents, which could be very useful to distinguish the F1 from its parental lines. In addition, 5 primer pairs were selected as special primer pairs for five hybrid rice combinations respectively. By combining the rapid, simple method on DNA extraction, it is suggested that SSR technique has wide prospective in variety authentication and purity identification.
基金the National Science Foundation of China(Nos.50934001 and 51322402)the National High-Tech Research and Development Program of China (No.2012AA062302)+2 种基金the Program of the Co-construction with Beijing Municipal Commission of Education of China (Nos.00012047 and 00012085)the Program for New Century Excellent Talents in Universities(NCET-11-0577)the Fundamental Research Funds for the Central Universities(No.FRF-AS-11-003A)
文摘TiClx （x=2.17） was prepared by using titanium sponge to reduce the concentration of TiCl4 in a NaCl-KCl melt under negative pressure. The as-prepared NaCl-KCl-TiClx melt was employed as the electrolyte, and two parallel crude titanium plates and one high-purity titanium plate were used as the anode and cathode, respectively. A series of electrochemical tests were performed to investigate the influence of electrolytic parameters on the current efficiency and quality of cathodic products. The results indicated that the quality of cathodic products was related to the current efficiency, which is significantly dependent on the current density and the initial concentration of titanium ions. The significance of this study is the attainment of high-purity titanium with a low oxygen content of 30× 10^-6.
