Ammonium 5-sulfosalicylic acid monohydrate (NH4·C7H5O6S·H2O, ASSA) was synthesized and optical grade crystal with dimensions of 45ram × 20mm × 18mm was obtained from aqueous solution by the cooli...Ammonium 5-sulfosalicylic acid monohydrate (NH4·C7H5O6S·H2O, ASSA) was synthesized and optical grade crystal with dimensions of 45ram × 20mm × 18mm was obtained from aqueous solution by the cooling solution method. The crystal structure was confirmed by X-ray single-crystal diffraction method and the empirical composition is C7HIINO7S with formula weight 253.23. The crystal belongs to monoclinic space group P21/c with a = 1 1.884(9), b = 7.306(5), c = 12.152(9) A, β = 104.851(13)°, V= 1019.8(13) A3, Z = 4, Dc = 1.649 g/cm3,μ = 0.340 mm-1, F(000) =528, the final R= 0.0307 and wR= 0.0866 for 7494 observed reflections (I〉 2σ(I)), Elemental analysis, 1R and 1H-NMR spectrum were used to characterize the compound. Thermal analysis showed that one coordination water molecule was contained and dehydration temperature of ASSA crystal was 106℃. Optical transmission and fluorescence spectrum revealed that the ASSA crystal exhibited a strong absorption in ultraviolet region with the sharp absorption edge located at 340 nm and a significant blue fluorescent emission band at 442 nm.展开更多
The title compound 1-(3-amino-[1,2,4]triazol-1-yl)-3,3-dimethyl-butan-2-one(3) was synthesized by Hofmann-alkylation reaction of 1-chloro-3,3-dimethyl-butan-2-one(1) and ~1H-[1,2,4]triazol-3-ylamine(2) with eq...The title compound 1-(3-amino-[1,2,4]triazol-1-yl)-3,3-dimethyl-butan-2-one(3) was synthesized by Hofmann-alkylation reaction of 1-chloro-3,3-dimethyl-butan-2-one(1) and ~1H-[1,2,4]triazol-3-ylamine(2) with equal amount of K_2CO_3 as acid acceptor. The structure of compound 3 was characterized by ~1H NMR, 13 C NMR, HRMS and single-crystal X-ray diffraction. The compound crystallizes in the monoclinic system, space group P21/n with a = 5.7227(8), b = 27.924(4), c = 6.2282(7) ?, β = 101.892(11)°, V = 973.9(2) ?~3, Z = 4, T = 180.00(10) K, μ(MoKα) = 0.087 mm^(-1), Dc = 1.243 g/cm^3, 3832 reflections measured(3.648≤θ≤26.022°), 1916 unique reflections(Rint = 0.0359, Rsigma = 0.0572) used in all calculations. The final R = 0.0557(I 〉 2σ(I)) and w R = 0.1276(all data). Bioassay showed that 3 displayed excellent activity as plant growth regulator with inducing lateral root formation and enhancing primary root elongation at 0.27 mmol/L(50 ppm) in soybeen(He Feng-50). Good water solubility was found with 50 mg in 1 m L of water. Therefore, application of 3 in agriculture is more environmentally friendly due to cosolvent-free condition, and results in improved abiotic-stress tolerance by affecting the root growth. And furthermore, it can be used as a precursor to investigate the function of regulating plant root growth.展开更多
The InGaAs/InAIAs/InP high electron mobility transistor (HEM:F) structures with lattice-matched and pseudo- morphic channels are grown by gas source molecular beam epitaxy. Effects of Si ^-doping condition and grow...The InGaAs/InAIAs/InP high electron mobility transistor (HEM:F) structures with lattice-matched and pseudo- morphic channels are grown by gas source molecular beam epitaxy. Effects of Si ^-doping condition and growth interruption on the electrical properties are investigated by changing the Si-cell temperature, doping time and growth process. It is found that the optimal Si ^-doping concentration (Nd) is about 5.0 x 1012 cm-2 and the use of growth interruption has a dramatic effect on the improvement of electrical properties. The material structure and crystal interface are analyzed by secondary ion mass spectroscopy and high resolution transmission elec- tron microscopy. An InGaAs/InAiAs/InP HEMT device with a gate length of lOOnm is fabricated. The device presents good pinch-off characteristics and the kink-effect of the device is trifling. In addition, the device exhibits fT = 249 GHa and fmax 〉 400 GHz.展开更多
At a working conference, Vice Mayor Lu Yucheng presented a plan for Beijing’s 1997 work in foreign trade and economic cooperation. The general task is to carry out the strategy of great economy and trade, expand expo...At a working conference, Vice Mayor Lu Yucheng presented a plan for Beijing’s 1997 work in foreign trade and economic cooperation. The general task is to carry out the strategy of great economy and trade, expand exports, use foreign funds reasonably and effectively, and conduct international economic and technical cooperation. The major target is to complete export volume of US$2.3 billion. Last year’s import and展开更多
Background: Insulin-like factor 2(IGF2) plays an important role in embryonic growth process by modulating intermediary metabolism and cell proliferation. Folic acid is involved in one carbon metabolism and contribu...Background: Insulin-like factor 2(IGF2) plays an important role in embryonic growth process by modulating intermediary metabolism and cell proliferation. Folic acid is involved in one carbon metabolism and contributes to DNA methylation which is related to gene expression. The purpose of this study was to explore whether folic acid could regulate IGF2 expression via epigenetic mechanism and further promote embryonic growth of new-hatched broilers.Methods: In the present study, 360 fertile eggs were selected and randomly assigned to four treatments. On11 embryonic day of incubation(E11), 0, 50, 100 and 150 μg folic acid were injected into eggs respectively.After hatched, growth performance of broilers were calculated. Hepatic IGF2 expression, methylation level and chromatin structure of promoter region were analyzed.Results: Results have showed that IGF2 expression was up-regulated in 150 μg folic acid group(P 〈 0.05) and other two dose of folic acid did not affect gene expression(P 〉 0.05). Meanwhile, methylation level of IGF2 promoter were lower in 100 and 150 μg groups, which was consistent with lower expression of DNA methyltransferase1(DNMT1)(P 〈 0.05). What's more, chromatin looseness of IGF2 promoter was higher in 150 μg group than control group(P 〈 0.05). Further, birth weight(BW), liver and bursa index of new-hatched chickens in 150 μg folic acid group were higher than the other groups(P 〈 0.05). There were positive correlations between hepatic IGF2 expression and BW and organs index(P 〈 0.05).Conclusion: In conclusion, our data have demonstrated that 150 μg folic acid injection on E11 could up-regulate IGF2 expression by modulating DNA hypomethylation and improving chromatin accessibility in the gene promoter region,and ulteriorly facilitate embryonic growth and organ development of broilers.展开更多
Solid-state reaction of praseodymium (III) oxide,K2CO3 and MoO3 at high temperature leads to a potassium lanthanide double molybdate,namely,KPr(MoO4)2. The structural and optical properties of the title compound h...Solid-state reaction of praseodymium (III) oxide,K2CO3 and MoO3 at high temperature leads to a potassium lanthanide double molybdate,namely,KPr(MoO4)2. The structural and optical properties of the title compound have been investigated by means of single-crystal X-ray diffraction and spectroscopic measurements at room temperature. KPr(MoO4)2 crystallizes in tetragonal,space group I41/a with a = 5.401(3),c = 12.044(10),Z = 2 and R (I 〉 2σ(I)) = 0.0416. It features the famous scheelite-type structure (CaWO4),which can be thought as the substitution of two Ca^2+ ions in CaWO4 by a couple of K^+ and Pr^3+ ions in a statistical manner,and W^6+ by Mo^6+ cations.展开更多
Brown needle-like crystals of CaEr2S4 were isolated as the major product from a reaction of elements and binary sulfides by a two-step flux technique. CaEr2S4 crystallizes in the orthorhombic space group Pnma with a=1...Brown needle-like crystals of CaEr2S4 were isolated as the major product from a reaction of elements and binary sulfides by a two-step flux technique. CaEr2S4 crystallizes in the orthorhombic space group Pnma with a=12.845(4), b=3.862(4), c=13.001(2)(A), V=645.0(7)(A)3,Z=4, F(000)=880,μ(MoKα)=27.794 mm^-1, the final R=0.0528 and wR=0.0562 for 1070observed reflections with I 〉 3σ(I). The CaEr2S4 structure forms a three-dimensional framework that consists of interconnected tetra-octahedral Er4S18 fragments. Ca^2+cations, in a monocapped trigonal prism geometry, are stuffed in two parallel rows into the one-dimensional channels along the b direction. CaEr2S4 is an infrared-transparent semiconductor with a band gap of 1.81 eV. Magnetic susceptibility measurements over 6~300 K indicate a Curie-Weiss paramagnetic behavior for the phase, with an effective magnetic moment of 9.64(1) μB per Er^3+ ion.展开更多
Experiments with tetcyclacis applied as a seed-dressing carried out with triticale cv. lasko in pots in the glasshouse and in hand-sown plots in the field. The results showed that tetcyclacis significantly delayed see...Experiments with tetcyclacis applied as a seed-dressing carried out with triticale cv. lasko in pots in the glasshouse and in hand-sown plots in the field. The results showed that tetcyclacis significantly delayed seedling emergence and inhibited the elongating growth in plant seedling stage, but not affected the growth and development of the adult plant during the late stage of stem extension and the stage of grain expansion. No significant difference was found in fertile stem number, grain quality and yield between the treated plants with tetcyclacis and control.展开更多
Most major oil zones in the Daqing Oilfield have reached a later,high water cut stage,but oil recovery is still only approximately 35%,and 50%of reserves remain to be recovered.The remaining oil is primarily distribut...Most major oil zones in the Daqing Oilfield have reached a later,high water cut stage,but oil recovery is still only approximately 35%,and 50%of reserves remain to be recovered.The remaining oil is primarily distributed at the edge of faults,in poor sand bodies,and in insufficiently injected and produced areas.Therefore,the edge of faults is a major target for remaining oil enrichment and potential tapping.Based on the dynamic change of production from development wells determined by the injection-recovery relationship at the edge of faults,we analyzed the control of structural features of faults on remaining oil enrichment at the edge.Our results show that the macroscopic structural features and their geometric relationship with sand bodies controlled remaining oil enrichment zones like the edges of NNE-striking faults,the footwalls of antithetic faults,the hard linkage segments(two faults had linked together with each other to form a bigger through-going fault),the tips of faults,and the oblique anticlines of soft linkages.Fault edges formed two types of forward microamplitude structures:(1) the tilted uplift of footwalls controlled by inverse fault sections and(2) the hanging-wall horizontal anticlines controlled by synthetic fault points.The remaining oil distribution was controlled by microamplitude structures.Consequently,such zones as the tilted uplift of the footwall of the NNW-striking antithetic faults with a fault throw larger than 40 m,the hard linkage segments,the tips of faults,and the oblique anticlines of soft linkage were favorable for tapping the remaining oil potential.Multi-target directional drilling was used for remaining oil development at fault edges.Reasonable fault spacing was determined on the basis of fault combinations and width of the shattered zone.Well core and log data revealed that the width of the shattered zone on the side of the fault core was less than 15 m in general;therefore,the distance from a fault to the development target should be larger than 15 m.Vertically segmented growth faults should take the separation of the lateral overlap of faults into account.Therefore,the safe distance of remaining oil well deployment at the fault edge should be larger than the sum of the width of shattered zone in faults and the separation of growth faults by vertical segmentation.展开更多
One-dimensional Nd doped CePO4 hexagonal nanowires have been synthesized for the first time at 140 ℃ for 24 hours via a hydrothermal method using P123 surfactant as the template.The products were characterized by X-r...One-dimensional Nd doped CePO4 hexagonal nanowires have been synthesized for the first time at 140 ℃ for 24 hours via a hydrothermal method using P123 surfactant as the template.The products were characterized by X-ray diffraction,transmission electron microscopy,photoluminescence and high-resolution transmission electron microscopy.Compared with CePO4,one-dimensional nanomaterials we have synthesized,Nd doped CePO4 nanomaterials remain their hexagonal one-dimensional morphology and smooth surface.However,their photoluminescence emissions are greatly enhanced at the wavelength of 348 nm.With their novel fluorescence-emission property,the Nd doped CePO4 nanomaterials are potential in many fields such as optics and electronics.展开更多
The microphysical structure of snow clouds and the growth process of snow crystals were observed by means of instrumented aircraft, weather radar, snow crystal observations etc. in Urumqi region during the winter of 1...The microphysical structure of snow clouds and the growth process of snow crystals were observed by means of instrumented aircraft, weather radar, snow crystal observations etc. in Urumqi region during the winter of 1982. The analysis of three cases show that about 70% of snow mass growth is produced in the lower layer below 2000 m under the cold front, and that the concentration of ice crystals is as high as 60 L^(-1) and the supercooled water is absent in lower clouds. We may infer that the deposition of ice crystals and the aggregation of snow crystals are important processes for the snow development. The microphysical structure of the snow band near the front aloft and its characteristics as a seeder cloud are also described in this paper.展开更多
ZSM-22 (TON) zeolite crystal morphology was successfully controlled using a microwave-assisted solvothermal fabrication method. Different co-solvents, including ethanol, 2-propanol, glycerol, and ethylene glycol, we...ZSM-22 (TON) zeolite crystal morphology was successfully controlled using a microwave-assisted solvothermal fabrication method. Different co-solvents, including ethanol, 2-propanol, glycerol, and ethylene glycol, were also applied in the synthesis mixture. The effects of various parameters such as the aging time, the type and amount of co-solvent on the ZSM-22 crystal aspect ratio were investigated. When employing this microwave irradiation synthesis, a long aging time was crucial to obtain smaller and more uniform crystal sizes. The addition of co-solvent resulted in elongated ZSM-22 crystals, regard- less of the actual co-solvent used, although ZSM-22 zeolite crystallinity was sensitive to the co-solvent type. In general, the use of a co-solvent stimulated the appearance of ZSM-5 zeolite as an impurity and the amount of this impurity was proportional to the concentration of co-solvent in the synthesis mixture.展开更多
基金carried out under the sponsorship and financial support from the Key Laboratory of Optoelectronic Materials Chemistry and Physics,Chinese Academy of Sciences
文摘Ammonium 5-sulfosalicylic acid monohydrate (NH4·C7H5O6S·H2O, ASSA) was synthesized and optical grade crystal with dimensions of 45ram × 20mm × 18mm was obtained from aqueous solution by the cooling solution method. The crystal structure was confirmed by X-ray single-crystal diffraction method and the empirical composition is C7HIINO7S with formula weight 253.23. The crystal belongs to monoclinic space group P21/c with a = 1 1.884(9), b = 7.306(5), c = 12.152(9) A, β = 104.851(13)°, V= 1019.8(13) A3, Z = 4, Dc = 1.649 g/cm3,μ = 0.340 mm-1, F(000) =528, the final R= 0.0307 and wR= 0.0866 for 7494 observed reflections (I〉 2σ(I)), Elemental analysis, 1R and 1H-NMR spectrum were used to characterize the compound. Thermal analysis showed that one coordination water molecule was contained and dehydration temperature of ASSA crystal was 106℃. Optical transmission and fluorescence spectrum revealed that the ASSA crystal exhibited a strong absorption in ultraviolet region with the sharp absorption edge located at 340 nm and a significant blue fluorescent emission band at 442 nm.
基金supported by the National Natural Science Foundation of China(No.2012BAD20B04)
文摘The title compound 1-(3-amino-[1,2,4]triazol-1-yl)-3,3-dimethyl-butan-2-one(3) was synthesized by Hofmann-alkylation reaction of 1-chloro-3,3-dimethyl-butan-2-one(1) and ~1H-[1,2,4]triazol-3-ylamine(2) with equal amount of K_2CO_3 as acid acceptor. The structure of compound 3 was characterized by ~1H NMR, 13 C NMR, HRMS and single-crystal X-ray diffraction. The compound crystallizes in the monoclinic system, space group P21/n with a = 5.7227(8), b = 27.924(4), c = 6.2282(7) ?, β = 101.892(11)°, V = 973.9(2) ?~3, Z = 4, T = 180.00(10) K, μ(MoKα) = 0.087 mm^(-1), Dc = 1.243 g/cm^3, 3832 reflections measured(3.648≤θ≤26.022°), 1916 unique reflections(Rint = 0.0359, Rsigma = 0.0572) used in all calculations. The final R = 0.0557(I 〉 2σ(I)) and w R = 0.1276(all data). Bioassay showed that 3 displayed excellent activity as plant growth regulator with inducing lateral root formation and enhancing primary root elongation at 0.27 mmol/L(50 ppm) in soybeen(He Feng-50). Good water solubility was found with 50 mg in 1 m L of water. Therefore, application of 3 in agriculture is more environmentally friendly due to cosolvent-free condition, and results in improved abiotic-stress tolerance by affecting the root growth. And furthermore, it can be used as a precursor to investigate the function of regulating plant root growth.
基金Supported by the National Natural Science Foundation of China under Grant No 61434006
文摘The InGaAs/InAIAs/InP high electron mobility transistor (HEM:F) structures with lattice-matched and pseudo- morphic channels are grown by gas source molecular beam epitaxy. Effects of Si ^-doping condition and growth interruption on the electrical properties are investigated by changing the Si-cell temperature, doping time and growth process. It is found that the optimal Si ^-doping concentration (Nd) is about 5.0 x 1012 cm-2 and the use of growth interruption has a dramatic effect on the improvement of electrical properties. The material structure and crystal interface are analyzed by secondary ion mass spectroscopy and high resolution transmission elec- tron microscopy. An InGaAs/InAiAs/InP HEMT device with a gate length of lOOnm is fabricated. The device presents good pinch-off characteristics and the kink-effect of the device is trifling. In addition, the device exhibits fT = 249 GHa and fmax 〉 400 GHz.
文摘At a working conference, Vice Mayor Lu Yucheng presented a plan for Beijing’s 1997 work in foreign trade and economic cooperation. The general task is to carry out the strategy of great economy and trade, expand exports, use foreign funds reasonably and effectively, and conduct international economic and technical cooperation. The major target is to complete export volume of US$2.3 billion. Last year’s import and
基金supported by the Natural Science Foundation of China (No. 31272464)the Program for New Century Excellent Talents (NCET-12-0476)the Program for Shaanxi Science & Technology (2014 K01-18-02, 2015NY149, 2015KTCQ02-19)
文摘Background: Insulin-like factor 2(IGF2) plays an important role in embryonic growth process by modulating intermediary metabolism and cell proliferation. Folic acid is involved in one carbon metabolism and contributes to DNA methylation which is related to gene expression. The purpose of this study was to explore whether folic acid could regulate IGF2 expression via epigenetic mechanism and further promote embryonic growth of new-hatched broilers.Methods: In the present study, 360 fertile eggs were selected and randomly assigned to four treatments. On11 embryonic day of incubation(E11), 0, 50, 100 and 150 μg folic acid were injected into eggs respectively.After hatched, growth performance of broilers were calculated. Hepatic IGF2 expression, methylation level and chromatin structure of promoter region were analyzed.Results: Results have showed that IGF2 expression was up-regulated in 150 μg folic acid group(P 〈 0.05) and other two dose of folic acid did not affect gene expression(P 〉 0.05). Meanwhile, methylation level of IGF2 promoter were lower in 100 and 150 μg groups, which was consistent with lower expression of DNA methyltransferase1(DNMT1)(P 〈 0.05). What's more, chromatin looseness of IGF2 promoter was higher in 150 μg group than control group(P 〈 0.05). Further, birth weight(BW), liver and bursa index of new-hatched chickens in 150 μg folic acid group were higher than the other groups(P 〈 0.05). There were positive correlations between hepatic IGF2 expression and BW and organs index(P 〈 0.05).Conclusion: In conclusion, our data have demonstrated that 150 μg folic acid injection on E11 could up-regulate IGF2 expression by modulating DNA hypomethylation and improving chromatin accessibility in the gene promoter region,and ulteriorly facilitate embryonic growth and organ development of broilers.
基金Supported by the NNSFC (20373073)the National Basic Research Program of China (No. 2007CB815307)+2 种基金the Funds of CAS (KJCX2-YW-H01)Fujian Key Laboratory of Nanomaterials (No. 2006L2005)the Knowledge Innovation Program of CAS
文摘Solid-state reaction of praseodymium (III) oxide,K2CO3 and MoO3 at high temperature leads to a potassium lanthanide double molybdate,namely,KPr(MoO4)2. The structural and optical properties of the title compound have been investigated by means of single-crystal X-ray diffraction and spectroscopic measurements at room temperature. KPr(MoO4)2 crystallizes in tetragonal,space group I41/a with a = 5.401(3),c = 12.044(10),Z = 2 and R (I 〉 2σ(I)) = 0.0416. It features the famous scheelite-type structure (CaWO4),which can be thought as the substitution of two Ca^2+ ions in CaWO4 by a couple of K^+ and Pr^3+ ions in a statistical manner,and W^6+ by Mo^6+ cations.
基金This work was partially supported by the NSF of Fujian Province (Z0513020, A042002)the NSF for Distinguished Young Scientist of China (20425104) and the NSF of CAS (KJCX2-SW-h05)
文摘Brown needle-like crystals of CaEr2S4 were isolated as the major product from a reaction of elements and binary sulfides by a two-step flux technique. CaEr2S4 crystallizes in the orthorhombic space group Pnma with a=12.845(4), b=3.862(4), c=13.001(2)(A), V=645.0(7)(A)3,Z=4, F(000)=880,μ(MoKα)=27.794 mm^-1, the final R=0.0528 and wR=0.0562 for 1070observed reflections with I 〉 3σ(I). The CaEr2S4 structure forms a three-dimensional framework that consists of interconnected tetra-octahedral Er4S18 fragments. Ca^2+cations, in a monocapped trigonal prism geometry, are stuffed in two parallel rows into the one-dimensional channels along the b direction. CaEr2S4 is an infrared-transparent semiconductor with a band gap of 1.81 eV. Magnetic susceptibility measurements over 6~300 K indicate a Curie-Weiss paramagnetic behavior for the phase, with an effective magnetic moment of 9.64(1) μB per Er^3+ ion.
文摘Experiments with tetcyclacis applied as a seed-dressing carried out with triticale cv. lasko in pots in the glasshouse and in hand-sown plots in the field. The results showed that tetcyclacis significantly delayed seedling emergence and inhibited the elongating growth in plant seedling stage, but not affected the growth and development of the adult plant during the late stage of stem extension and the stage of grain expansion. No significant difference was found in fertile stem number, grain quality and yield between the treated plants with tetcyclacis and control.
基金financial support from the Natural Science Foundation of China (Grant No. 41272151, 41472126)the Natural Science Foundation for Distinguished Young Scholars of Heilongjiang Province, China (Grant No. JC201304)+1 种基金the Joint Funds of the National Natural Science Foundation of China (Grant No. U1562214)the Program for Huabei Oilfield (Grant No. HBYT-CY5-2015-JS-127)
文摘Most major oil zones in the Daqing Oilfield have reached a later,high water cut stage,but oil recovery is still only approximately 35%,and 50%of reserves remain to be recovered.The remaining oil is primarily distributed at the edge of faults,in poor sand bodies,and in insufficiently injected and produced areas.Therefore,the edge of faults is a major target for remaining oil enrichment and potential tapping.Based on the dynamic change of production from development wells determined by the injection-recovery relationship at the edge of faults,we analyzed the control of structural features of faults on remaining oil enrichment at the edge.Our results show that the macroscopic structural features and their geometric relationship with sand bodies controlled remaining oil enrichment zones like the edges of NNE-striking faults,the footwalls of antithetic faults,the hard linkage segments(two faults had linked together with each other to form a bigger through-going fault),the tips of faults,and the oblique anticlines of soft linkages.Fault edges formed two types of forward microamplitude structures:(1) the tilted uplift of footwalls controlled by inverse fault sections and(2) the hanging-wall horizontal anticlines controlled by synthetic fault points.The remaining oil distribution was controlled by microamplitude structures.Consequently,such zones as the tilted uplift of the footwall of the NNW-striking antithetic faults with a fault throw larger than 40 m,the hard linkage segments,the tips of faults,and the oblique anticlines of soft linkage were favorable for tapping the remaining oil potential.Multi-target directional drilling was used for remaining oil development at fault edges.Reasonable fault spacing was determined on the basis of fault combinations and width of the shattered zone.Well core and log data revealed that the width of the shattered zone on the side of the fault core was less than 15 m in general;therefore,the distance from a fault to the development target should be larger than 15 m.Vertically segmented growth faults should take the separation of the lateral overlap of faults into account.Therefore,the safe distance of remaining oil well deployment at the fault edge should be larger than the sum of the width of shattered zone in faults and the separation of growth faults by vertical segmentation.
文摘One-dimensional Nd doped CePO4 hexagonal nanowires have been synthesized for the first time at 140 ℃ for 24 hours via a hydrothermal method using P123 surfactant as the template.The products were characterized by X-ray diffraction,transmission electron microscopy,photoluminescence and high-resolution transmission electron microscopy.Compared with CePO4,one-dimensional nanomaterials we have synthesized,Nd doped CePO4 nanomaterials remain their hexagonal one-dimensional morphology and smooth surface.However,their photoluminescence emissions are greatly enhanced at the wavelength of 348 nm.With their novel fluorescence-emission property,the Nd doped CePO4 nanomaterials are potential in many fields such as optics and electronics.
文摘The microphysical structure of snow clouds and the growth process of snow crystals were observed by means of instrumented aircraft, weather radar, snow crystal observations etc. in Urumqi region during the winter of 1982. The analysis of three cases show that about 70% of snow mass growth is produced in the lower layer below 2000 m under the cold front, and that the concentration of ice crystals is as high as 60 L^(-1) and the supercooled water is absent in lower clouds. We may infer that the deposition of ice crystals and the aggregation of snow crystals are important processes for the snow development. The microphysical structure of the snow band near the front aloft and its characteristics as a seeder cloud are also described in this paper.
文摘ZSM-22 (TON) zeolite crystal morphology was successfully controlled using a microwave-assisted solvothermal fabrication method. Different co-solvents, including ethanol, 2-propanol, glycerol, and ethylene glycol, were also applied in the synthesis mixture. The effects of various parameters such as the aging time, the type and amount of co-solvent on the ZSM-22 crystal aspect ratio were investigated. When employing this microwave irradiation synthesis, a long aging time was crucial to obtain smaller and more uniform crystal sizes. The addition of co-solvent resulted in elongated ZSM-22 crystals, regard- less of the actual co-solvent used, although ZSM-22 zeolite crystallinity was sensitive to the co-solvent type. In general, the use of a co-solvent stimulated the appearance of ZSM-5 zeolite as an impurity and the amount of this impurity was proportional to the concentration of co-solvent in the synthesis mixture.