This study was aimed to investigate the effects of hydrothermal aging, propene and SO<sub>2</sub> poisoning on the ammonia-selective catalytic reduction (NH<sub>3</sub>-SCR) performance of both...This study was aimed to investigate the effects of hydrothermal aging, propene and SO<sub>2</sub> poisoning on the ammonia-selective catalytic reduction (NH<sub>3</sub>-SCR) performance of both Cu-SAPO-34 and Cu-ZSM-5. The catalytic activities of fresh, aged and poisoned samples were tested in ammonia-selective catalytic reduction (NH<sub>3</sub>-SCR) of NO<sub>x</sub> conditions. The XRD, TG and N<sub>2</sub>-desorption results showed that the structures of the Cu-SAPO-34 and Cu-ZSM-5 remained intact after 750˚C hydrothermally aged, SO<sub>2</sub> and propene poisoned. After hydrothermal aging at 750˚C for 12 h, the NO reduction performance of Cu-ZSM-5 was significantly reduced at lower temperatures, while that of Cu-SAPO-34 was less affected. Moreover, Cu-SAPO-34 catalyst showed high NO conversion with SO<sub>2</sub> or propene compared to Cu-ZSM-5. However, Cu-ZSM-5 showed a larger drop in catalytic activity with SO<sub>2</sub> or propene compared to Cu-SAPO-34 catalyst. The H<sub>2</sub>-TPR results showed that Cu<sup>2 </sup> ions could be reduced to Cu<sup> </sup> and Cu<sup>0</sup> for Cu-ZSM-5, while no significant transformation of copper species was observed for Cu-SAPO-34. Meanwhile, the UV-vis DRS results showed that CuO species were formed in Cu-ZSM-5, while little changes were observed for the Cu-SAPO-34. Cu-SAPO-34 showed high sulfur and hydrocarbon poison resistance compared to Cu-ZSM-5. In summary, Cu-SAPO-34 with small-pore zeolite showed higher hydrothermal stability and better hydrocarbon and sulfur poison resistant than Cu-ZSM-5 with medium-pore.展开更多
Electroless Ni-Co-P-coating of fly-ash cenosphere particles is demonstrated in the present investigation. The Electroless Ni-Co-P-coating process is modified by replacing the conventional sensitization and activation ...Electroless Ni-Co-P-coating of fly-ash cenosphere particles is demonstrated in the present investigation. The Electroless Ni-Co-P-coating process is modified by replacing the conventional sensitization and activation steps with only using activation step with Ag(NH3)2+ activator. The cenospheres are characterized by scanning electron microscope (SEM), energy dispersive spectroscopy (EDX), X-ray diffraction analysis (XRD) and X-ray photoelectron spectroscopy (XPS) during and after the coating process. Relatively uniform coating is obtained under the given coating conditions. The possible mechanism of electroless Ni-Co-P-coating of cenospheres utilizing Ag(NH3)2+ activator is suggested. The low density Ni-Co-P coated cenospheres may be utilized for manufacturing conducting polymers for EMI-shielding application and microwave absorbing materials.展开更多
In this paper, a novel polymeric complex [MnNa（Salicylate）2（CH3OH）（H2O）]n·0.5nH2O was obtained and characterized by IR spectra, elemental analysis and single crystal X-ray diffraction. The titled complex is...In this paper, a novel polymeric complex [MnNa（Salicylate）2（CH3OH）（H2O）]n·0.5nH2O was obtained and characterized by IR spectra, elemental analysis and single crystal X-ray diffraction. The titled complex is crystallized in triclinic system, space group P1 with a=0.763 82（15） nm, b= 1.037 1（2） nm, c=1.290 9（3） nm, α= 103.59（3）°, β=104.65（3）°, γ=109.50（3）°, V=0.873 6（3） nm 3, Z=2, Dc=1.556 Mg/m 3, Mr=409.20, μ=0.823 mm -1, F（000）=418, R=0.0614, wR= 0.147 6. The activity in catalyzing the superoxygen anionic free radical dismutation was determinated.展开更多
目的了解西安市3~18儿童维生素D[25(OH)VitD,简称VitD]的营养状况及影响因素。方法选择2015年7月到2017年2月期间的寒、暑假在西安交通大学第一附属医院儿保科做健康体检的533例3~18岁西安市儿童为研究对象,采用酶联免疫吸附法(ELISA)...目的了解西安市3~18儿童维生素D[25(OH)VitD,简称VitD]的营养状况及影响因素。方法选择2015年7月到2017年2月期间的寒、暑假在西安交通大学第一附属医院儿保科做健康体检的533例3~18岁西安市儿童为研究对象,采用酶联免疫吸附法(ELISA)检测其血清VitD水平,并分析季节和性别的影响;进一步按照被研究儿童所处学校的性质,将其分为幼儿园组,小学组和中学组,比较三组儿童VitD的营养状况。结果儿童血清VitD水平为24.94±1.03ng/mL,VitD缺乏和不足的检出率分别为34.71%(185/533)和34.15%(182/533)。寒假与暑假儿童VitD水平(21.20±11.01ng/mL vs 27.71±8.68ng/mL,t=7.62,P<0.001)及不同VitD水平的检出率差异均有统计学意义(57.71%vs 17.64%,χ~2=93.13,P<0.001)。男童与女童VitD水平(25.06±10.67ng/mL vs 24.72±9.52ng/mL,t=0.38,P>0.05)及VitD缺乏检出率(35.03%vs 34.17%,χ~2=0.04,P>0.05)差异均无统计学意义。幼儿园组、小学组和中学组VitD水平分别为31.93±10.02ng/mL、22.33±8.34ng/mL和19.45±7.27ng/mL(各组间比较t值分别为10.56、10.49和2.19,均P<0.05),且三组儿童不同水平VitD的检出率差异存在统计学意义(χ~2=125.82,P<0.05)。结论西安市3~18岁儿童VitD缺乏率较高,尤其是中、小学阶段的儿童更为突出,医务人员应重视对该部分儿童VitD营养的保健指导。展开更多
The preparation of Cu nanoparticles by the aqueous solution reduction method was investigated. The effects of different reaction parameters on the preparation of Cu nanoparticles were studied. The optimum conditions f...The preparation of Cu nanoparticles by the aqueous solution reduction method was investigated. The effects of different reaction parameters on the preparation of Cu nanoparticles were studied. The optimum conditions for preparing well-dispersed nanoparticles were found as follows: 0.4 mol/L NaBH4 was added into solution containing 0.2 mol/L Cu2+, 1.0% gelatin dispersant in mass fraction, and 1.2 mol/L NH3?H2O at pH 12 and 313 K. In addition, a series of experiments were performed to discover the reaction process. NH3?H2O was found to be able to modulate the reaction process. At pH=10, Cu2+ was transformed to Cu(NH3)42+ as precursor after the addition of NH3?H2O, and then Cu(NH3)42+ was reduced by NaBH4 solution. At pH=12, Cu2+ was transformed to Cu(OH)2 as precursor after the addition of NH3?H2O, and Cu(OH)2 was then reduced by NaBH4 solution.展开更多
文摘This study was aimed to investigate the effects of hydrothermal aging, propene and SO<sub>2</sub> poisoning on the ammonia-selective catalytic reduction (NH<sub>3</sub>-SCR) performance of both Cu-SAPO-34 and Cu-ZSM-5. The catalytic activities of fresh, aged and poisoned samples were tested in ammonia-selective catalytic reduction (NH<sub>3</sub>-SCR) of NO<sub>x</sub> conditions. The XRD, TG and N<sub>2</sub>-desorption results showed that the structures of the Cu-SAPO-34 and Cu-ZSM-5 remained intact after 750˚C hydrothermally aged, SO<sub>2</sub> and propene poisoned. After hydrothermal aging at 750˚C for 12 h, the NO reduction performance of Cu-ZSM-5 was significantly reduced at lower temperatures, while that of Cu-SAPO-34 was less affected. Moreover, Cu-SAPO-34 catalyst showed high NO conversion with SO<sub>2</sub> or propene compared to Cu-ZSM-5. However, Cu-ZSM-5 showed a larger drop in catalytic activity with SO<sub>2</sub> or propene compared to Cu-SAPO-34 catalyst. The H<sub>2</sub>-TPR results showed that Cu<sup>2 </sup> ions could be reduced to Cu<sup> </sup> and Cu<sup>0</sup> for Cu-ZSM-5, while no significant transformation of copper species was observed for Cu-SAPO-34. Meanwhile, the UV-vis DRS results showed that CuO species were formed in Cu-ZSM-5, while little changes were observed for the Cu-SAPO-34. Cu-SAPO-34 showed high sulfur and hydrocarbon poison resistance compared to Cu-ZSM-5. In summary, Cu-SAPO-34 with small-pore zeolite showed higher hydrothermal stability and better hydrocarbon and sulfur poison resistant than Cu-ZSM-5 with medium-pore.
基金sponsored by Hunan Provincial Natural Science Foundation of China(04JJ3035)the Research Fund of the Educational Ministry of Hunan Province(03B002)
文摘Electroless Ni-Co-P-coating of fly-ash cenosphere particles is demonstrated in the present investigation. The Electroless Ni-Co-P-coating process is modified by replacing the conventional sensitization and activation steps with only using activation step with Ag(NH3)2+ activator. The cenospheres are characterized by scanning electron microscope (SEM), energy dispersive spectroscopy (EDX), X-ray diffraction analysis (XRD) and X-ray photoelectron spectroscopy (XPS) during and after the coating process. Relatively uniform coating is obtained under the given coating conditions. The possible mechanism of electroless Ni-Co-P-coating of cenospheres utilizing Ag(NH3)2+ activator is suggested. The low density Ni-Co-P coated cenospheres may be utilized for manufacturing conducting polymers for EMI-shielding application and microwave absorbing materials.
文摘In this paper, a novel polymeric complex [MnNa（Salicylate）2（CH3OH）（H2O）]n·0.5nH2O was obtained and characterized by IR spectra, elemental analysis and single crystal X-ray diffraction. The titled complex is crystallized in triclinic system, space group P1 with a=0.763 82（15） nm, b= 1.037 1（2） nm, c=1.290 9（3） nm, α= 103.59（3）°, β=104.65（3）°, γ=109.50（3）°, V=0.873 6（3） nm 3, Z=2, Dc=1.556 Mg/m 3, Mr=409.20, μ=0.823 mm -1, F（000）=418, R=0.0614, wR= 0.147 6. The activity in catalyzing the superoxygen anionic free radical dismutation was determinated.
文摘目的了解西安市3~18儿童维生素D[25(OH)VitD,简称VitD]的营养状况及影响因素。方法选择2015年7月到2017年2月期间的寒、暑假在西安交通大学第一附属医院儿保科做健康体检的533例3~18岁西安市儿童为研究对象,采用酶联免疫吸附法(ELISA)检测其血清VitD水平,并分析季节和性别的影响;进一步按照被研究儿童所处学校的性质,将其分为幼儿园组,小学组和中学组,比较三组儿童VitD的营养状况。结果儿童血清VitD水平为24.94±1.03ng/mL,VitD缺乏和不足的检出率分别为34.71%(185/533)和34.15%(182/533)。寒假与暑假儿童VitD水平(21.20±11.01ng/mL vs 27.71±8.68ng/mL,t=7.62,P<0.001)及不同VitD水平的检出率差异均有统计学意义(57.71%vs 17.64%,χ~2=93.13,P<0.001)。男童与女童VitD水平(25.06±10.67ng/mL vs 24.72±9.52ng/mL,t=0.38,P>0.05)及VitD缺乏检出率(35.03%vs 34.17%,χ~2=0.04,P>0.05)差异均无统计学意义。幼儿园组、小学组和中学组VitD水平分别为31.93±10.02ng/mL、22.33±8.34ng/mL和19.45±7.27ng/mL(各组间比较t值分别为10.56、10.49和2.19,均P<0.05),且三组儿童不同水平VitD的检出率差异存在统计学意义(χ~2=125.82,P<0.05)。结论西安市3~18岁儿童VitD缺乏率较高,尤其是中、小学阶段的儿童更为突出,医务人员应重视对该部分儿童VitD营养的保健指导。
文摘The preparation of Cu nanoparticles by the aqueous solution reduction method was investigated. The effects of different reaction parameters on the preparation of Cu nanoparticles were studied. The optimum conditions for preparing well-dispersed nanoparticles were found as follows: 0.4 mol/L NaBH4 was added into solution containing 0.2 mol/L Cu2+, 1.0% gelatin dispersant in mass fraction, and 1.2 mol/L NH3?H2O at pH 12 and 313 K. In addition, a series of experiments were performed to discover the reaction process. NH3?H2O was found to be able to modulate the reaction process. At pH=10, Cu2+ was transformed to Cu(NH3)42+ as precursor after the addition of NH3?H2O, and then Cu(NH3)42+ was reduced by NaBH4 solution. At pH=12, Cu2+ was transformed to Cu(OH)2 as precursor after the addition of NH3?H2O, and Cu(OH)2 was then reduced by NaBH4 solution.
