The effects of B2O3 addition on both the sintering behavior and microwave dielectric properties of CaO-B2O3-SiO2 （CBS） glass ceramics were investigated by Fourier transform infrared spectroscopy （FTIR）, X-ray diff...The effects of B2O3 addition on both the sintering behavior and microwave dielectric properties of CaO-B2O3-SiO2 （CBS） glass ceramics were investigated by Fourier transform infrared spectroscopy （FTIR）, X-ray diffractometry （XRD） and scanning electron microscopy （SEM）. The results show that the increasing amount of B203 causes the increase of the contents of [BO3], [BO4] and [SiO4], which deduces the increase of CaB204 and a-SiO2 and the decrease of CaSiO3 correspondingly. No new phase is observed throughout the entire experiments. A bulk density of 2.54 g/cm3, a thermal expansion coefficient value of 11.95× 10-6 ℃-1 （20-500℃）, a dielectric constant er value of 6.42 and a dielectric loss tanδ value of 0.000 9 （measured at 9.7 GHz） are obtained for CBS glass ceramics containing 35%-B203 （mass fraction） sintered at 850 ℃ for 15 min.展开更多
In the present work, the effects of chemical compositions on the hydrogen blistering and hydrogen induced cracking of A350LF2 steel with different S contents were studied. Four types of A350LF2 steels were evaluated b...In the present work, the effects of chemical compositions on the hydrogen blistering and hydrogen induced cracking of A350LF2 steel with different S contents were studied. Four types of A350LF2 steels were evaluated by immersing samples in H2S-saturated NACE solution. The hydrogen blistering, crack length rate(CLR), crack thickness rate(CTR) and crack sensitivity rate(CSR) were evaluated. The results show that there are many hydrogen blisters on the sample surface with S content of 0.021%, a few on the sample surface with S content of 0.019% and 0.012% and no one on the surface with S content of 0.002%. There were 12, 2 and 1 strips of cracks of longer than 0.3 mm on the evaluated cross sections with S content of 0.021%, 0.019% and 0.012%, respectively. There was no any crack in the sample with 0.002% S. The corrosion rate was also evaluated. The S content has no obvious influence on the corrosion rate.展开更多
A series of 3.0Mo/(Hβ+γ-Al_(2)O_(3))samples withγ-Al_(2)O_(3)contents in the range of 0_100%(mass fraction)was studied by means of XRD,NH_(3)-TPD,TPR and BET determinations for characterizing their structures.The H...A series of 3.0Mo/(Hβ+γ-Al_(2)O_(3))samples withγ-Al_(2)O_(3)contents in the range of 0_100%(mass fraction)was studied by means of XRD,NH_(3)-TPD,TPR and BET determinations for characterizing their structures.The Hβzeolite structure in the 3.0Mo/Hβsample can be effectively stabilized by adding someγ-Al_(2)O_(3)to Hβzeolite.γ-Al_(2)O_(3)mainly favors the formation of polymolybdate or multilayered Mo oxide,while Hβmainly forms the Al_(2)(MoO_(4))_(3)species,as evaluated by the TPR technique.When used as the catalyst for the metathesis of butylene-2 and ethylene to propylene,there exists a close correlation between the specific surface area and stability of the catalyst.The specific surface area of the catalyst shows the maximum when{(Hβ+}γ-Al_(2)O_(3))contains 30%γ-Al_(2)O_(3),which is in agreement with that of the time needed for the reaction stablization.In the case of maximum surface area,the rate of coke deposition is the minimum.展开更多
基金Project(2007AA03Z0455) supported by the National High-Technology Research and Development Program of ChinaProject(BE2009168) supported by the Natural Science Foundation of Jiangsu Province in ChinaProject supported by the Priority Academic Program Development of Jiangsu Higher Education Institution,China
文摘The effects of B2O3 addition on both the sintering behavior and microwave dielectric properties of CaO-B2O3-SiO2 （CBS） glass ceramics were investigated by Fourier transform infrared spectroscopy （FTIR）, X-ray diffractometry （XRD） and scanning electron microscopy （SEM）. The results show that the increasing amount of B203 causes the increase of the contents of [BO3], [BO4] and [SiO4], which deduces the increase of CaB204 and a-SiO2 and the decrease of CaSiO3 correspondingly. No new phase is observed throughout the entire experiments. A bulk density of 2.54 g/cm3, a thermal expansion coefficient value of 11.95× 10-6 ℃-1 （20-500℃）, a dielectric constant er value of 6.42 and a dielectric loss tanδ value of 0.000 9 （measured at 9.7 GHz） are obtained for CBS glass ceramics containing 35%-B203 （mass fraction） sintered at 850 ℃ for 15 min.
文摘In the present work, the effects of chemical compositions on the hydrogen blistering and hydrogen induced cracking of A350LF2 steel with different S contents were studied. Four types of A350LF2 steels were evaluated by immersing samples in H2S-saturated NACE solution. The hydrogen blistering, crack length rate(CLR), crack thickness rate(CTR) and crack sensitivity rate(CSR) were evaluated. The results show that there are many hydrogen blisters on the sample surface with S content of 0.021%, a few on the sample surface with S content of 0.019% and 0.012% and no one on the surface with S content of 0.002%. There were 12, 2 and 1 strips of cracks of longer than 0.3 mm on the evaluated cross sections with S content of 0.021%, 0.019% and 0.012%, respectively. There was no any crack in the sample with 0.002% S. The corrosion rate was also evaluated. The S content has no obvious influence on the corrosion rate.
基金the National Natural Science Foundation of China(No.20303019)the National 973 Project of China(No.2003CB615802).
文摘A series of 3.0Mo/(Hβ+γ-Al_(2)O_(3))samples withγ-Al_(2)O_(3)contents in the range of 0_100%(mass fraction)was studied by means of XRD,NH_(3)-TPD,TPR and BET determinations for characterizing their structures.The Hβzeolite structure in the 3.0Mo/Hβsample can be effectively stabilized by adding someγ-Al_(2)O_(3)to Hβzeolite.γ-Al_(2)O_(3)mainly favors the formation of polymolybdate or multilayered Mo oxide,while Hβmainly forms the Al_(2)(MoO_(4))_(3)species,as evaluated by the TPR technique.When used as the catalyst for the metathesis of butylene-2 and ethylene to propylene,there exists a close correlation between the specific surface area and stability of the catalyst.The specific surface area of the catalyst shows the maximum when{(Hβ+}γ-Al_(2)O_(3))contains 30%γ-Al_(2)O_(3),which is in agreement with that of the time needed for the reaction stablization.In the case of maximum surface area,the rate of coke deposition is the minimum.
