ZrO2-mullite nano-ceramics were fabricated by in-situ controlled crystallizing from SiO2-Al2O3-ZrO2 amorphous bulk. The thermal transformation sequences of the SiO2-Al2O3-ZrO2 amorphous bulk were investigated by X-ray...ZrO2-mullite nano-ceramics were fabricated by in-situ controlled crystallizing from SiO2-Al2O3-ZrO2 amorphous bulk. The thermal transformation sequences of the SiO2-Al2O3-ZrO2 amorphous bulk were investigated by X-ray diffraction, infrared spectrum, scanning electron microscope and differential scanning calorimetric. And the mechanical properties of the nano-ceramics were studied. The results show that the bulks are still in amorphous state at 900 ℃ and the t-ZrO2 forms at about 950 ℃ with a faint spinel-like phase which changes into mullite on further heating. ZrO2 and mullite become major phases at 1 100 ℃ and an amount of m-ZrO2 occur at the same time. The sample heated at 950 ℃ for 2 h and then at 1 100 ℃ for 1 h shows very dense and homogenous microstructure with ball-like grains in size of 20-50 nm. With the increase of crystallization temperature up to 1 350 ℃, the grains grow quickly and some grow into lath-shaped grains with major diameter of 5 μm. After two-step treatment the highest micro-hardness, flexural strength and fracture toughness of the samples are 13.72 GPa, 520 MPa and 5.13 MPa·m1/2, respectively.展开更多
Pre-treatment, which supplies a stable, high-quality feed for reverse osmosis （RO） membranes, is a criti- cal step for successful operation in a seawater reverse osmosis plant. In this study, ceramic membrane system...Pre-treatment, which supplies a stable, high-quality feed for reverse osmosis （RO） membranes, is a criti- cal step for successful operation in a seawater reverse osmosis plant. In this study, ceramic membrane systems were employed as pre-treatment for seawater desalination. A laboratory experiment was performed to investigate the effect of the cross-flow velocity on the critical flux and consequently to optimize the permeate flux. Then a pilot test was performed to investigate the long-term performance. The result shows that there is no significant effect of the cross-flow velocity on the critical flux when the cross-flow velocity varies in laminar flow region only or in turbulent flow region only, but the effect is distinct when the cross-flow velocity varies in the transition region. The membrane fouling is slight at the permeate flux of 150 L·m^-2·h^-1 and the system is stable, producing a high-quality feed （the turbidity and silt density index are less than 0.1 NTU and 3.0, respectively） for RO to run for 2922.4 h without chemical cleaning. Thus the ceramic membranes are suitable to filtrate seawater as the pre-treatment for RO.展开更多
In this paper, fouling mechanisms of mullite ceramic membranes for treatment of oily wastewaters in hybrid coagulation-microfiltration （MF） process presented. Hermia＇s models for cross flow filtration were used to ...In this paper, fouling mechanisms of mullite ceramic membranes for treatment of oily wastewaters in hybrid coagulation-microfiltration （MF） process presented. Hermia＇s models for cross flow filtration were used to investigate the fouling mechanisms of membranes with various coagulating chemicals concentrations. Four coagu lating chemicals （FeC12.4H20, FeSO4.7H20, A1C13-6H20 and A12（SO4）3.18H20） plus Ca（OH）2 of the same concen- tration were evaluated in the coagulation-MF hybrid process with different concentrations （0, 50 mg.L-1, 100 mg.L-1 and 200 mg.L-1）. To determine whether the data agree with models under consideration, the coefficients of determination （R2） of all models were compared with one another. In addition, average prediction errors of models were calculated. The results showed that cake filtration model can be applied for prediction of permeation flux decline for MF and coagulation-（MF） hybrid process with the best average error equal to 0.09%. Results indicated that pore blocking behavior changes as time of filtration increases, and one model cannot predict pore blocking behavior in all filtration time with very good precision.展开更多
Ceramic ultrafiltration membranes were used to separate titanium silicalite-1 （TS-1） catalysts from the slurry of catalytic ammoximation of cyclohexanone to oxime. Silica was shown to have a great effect on membrane...Ceramic ultrafiltration membranes were used to separate titanium silicalite-1 （TS-1） catalysts from the slurry of catalytic ammoximation of cyclohexanone to oxime. Silica was shown to have a great effect on membrane fouling in the alkaline environment of this system. In the ammoximation system, there are three main silica sources, which are residual silica on the catalyst particles surface during preparation, silica dissolved from TS-1 catalyst particles by ammonia solvent, and silica sol added into the reaction slurry to inhibit the dissolution erosion of the TS-1 catalyst. The silica dissolved by ammonia has been proved to influence membrane fouling most among the three silica sources. This was because the amount of silica dissolved by ammonia was the largest, and the polymerization of silica monomers at high concentration caused colloid particles formation, which led to a dense cake layer depositing on the membrane surface. Meanwhile, the size reduction of catalyst particles caused by alkaline dissolution also increased specific resistances of cake layers.展开更多
AIM: To evaluate disease-specific quality of life (QOL) in liver cirrhosis patients and to compare it with those of a healthy population. Also an important objective was to assess whether QOL in liver cirrhosis patien...AIM: To evaluate disease-specific quality of life (QOL) in liver cirrhosis patients and to compare it with those of a healthy population. Also an important objective was to assess whether QOL in liver cirrhosis patients differs by age and gender, by type and severity of disease. METHODS: The case group of 131 liver cirrhosis patients was selected. The control group of 262 was enrolled from a healthy population according to the scheme of case-control study. Clinical, demographic, laboratory data were collected. QOL was measured with a specific chronic liver disease questionnaire (CLDQ), which was translated and validated in Lithuanian. QOL scores were compared between groups by age, gender, type and severity of disease. Cronbach’s alpha statistics calculation was used for evaluation of internal consistency reliability. Student’s t test or ANOVA were used for evaluation hypothesis about probability equation. RESULTS: QOL was significantly lower in liver cirrhosis patients than in healthy population (59.5 ± 18.3 vs 85.3 ± 12.3, P < 0.001). The significant QOL differences between case and control groups were observed in domains of worry and abdominal symptoms, the smaller differences-in emotional functions and systematic symptom domains. Significantly worse QOL was in observed patients with increased clinical severity of the disease measured by Child-Pugh class. Age, gender and etiology of disease had an insignificant effect on QOL in cirrhotic patients. CONCLUSION: QOL was significantly impaired in all CLDQ domains in liver cirrhosis patients. Increase in severity of disease was the major factor associated with poorer QOL.展开更多
基金Project(2003AA332040) supported by the National High Technology Research and Development Program of China
文摘ZrO2-mullite nano-ceramics were fabricated by in-situ controlled crystallizing from SiO2-Al2O3-ZrO2 amorphous bulk. The thermal transformation sequences of the SiO2-Al2O3-ZrO2 amorphous bulk were investigated by X-ray diffraction, infrared spectrum, scanning electron microscope and differential scanning calorimetric. And the mechanical properties of the nano-ceramics were studied. The results show that the bulks are still in amorphous state at 900 ℃ and the t-ZrO2 forms at about 950 ℃ with a faint spinel-like phase which changes into mullite on further heating. ZrO2 and mullite become major phases at 1 100 ℃ and an amount of m-ZrO2 occur at the same time. The sample heated at 950 ℃ for 2 h and then at 1 100 ℃ for 1 h shows very dense and homogenous microstructure with ball-like grains in size of 20-50 nm. With the increase of crystallization temperature up to 1 350 ℃, the grains grow quickly and some grow into lath-shaped grains with major diameter of 5 μm. After two-step treatment the highest micro-hardness, flexural strength and fracture toughness of the samples are 13.72 GPa, 520 MPa and 5.13 MPa·m1/2, respectively.
基金Supported by the National High Technology Research and Development of China (2007AA030303)
文摘Pre-treatment, which supplies a stable, high-quality feed for reverse osmosis （RO） membranes, is a criti- cal step for successful operation in a seawater reverse osmosis plant. In this study, ceramic membrane systems were employed as pre-treatment for seawater desalination. A laboratory experiment was performed to investigate the effect of the cross-flow velocity on the critical flux and consequently to optimize the permeate flux. Then a pilot test was performed to investigate the long-term performance. The result shows that there is no significant effect of the cross-flow velocity on the critical flux when the cross-flow velocity varies in laminar flow region only or in turbulent flow region only, but the effect is distinct when the cross-flow velocity varies in the transition region. The membrane fouling is slight at the permeate flux of 150 L·m^-2·h^-1 and the system is stable, producing a high-quality feed （the turbidity and silt density index are less than 0.1 NTU and 3.0, respectively） for RO to run for 2922.4 h without chemical cleaning. Thus the ceramic membranes are suitable to filtrate seawater as the pre-treatment for RO.
文摘In this paper, fouling mechanisms of mullite ceramic membranes for treatment of oily wastewaters in hybrid coagulation-microfiltration （MF） process presented. Hermia＇s models for cross flow filtration were used to investigate the fouling mechanisms of membranes with various coagulating chemicals concentrations. Four coagu lating chemicals （FeC12.4H20, FeSO4.7H20, A1C13-6H20 and A12（SO4）3.18H20） plus Ca（OH）2 of the same concen- tration were evaluated in the coagulation-MF hybrid process with different concentrations （0, 50 mg.L-1, 100 mg.L-1 and 200 mg.L-1）. To determine whether the data agree with models under consideration, the coefficients of determination （R2） of all models were compared with one another. In addition, average prediction errors of models were calculated. The results showed that cake filtration model can be applied for prediction of permeation flux decline for MF and coagulation-（MF） hybrid process with the best average error equal to 0.09%. Results indicated that pore blocking behavior changes as time of filtration increases, and one model cannot predict pore blocking behavior in all filtration time with very good precision.
基金Supported by the National Basic Research Program of China （2009CB623406）, the National Natural Science Foundation of China （20806038）, the Natural Science Foundation of Jiangsu Province （BK2008504）, the National Science Foundation for Postdoctoral Scientists of China （20070421005） and Jiangsu Planned Projects for Postdoctoral Research Funds （0702020B）.
文摘Ceramic ultrafiltration membranes were used to separate titanium silicalite-1 （TS-1） catalysts from the slurry of catalytic ammoximation of cyclohexanone to oxime. Silica was shown to have a great effect on membrane fouling in the alkaline environment of this system. In the ammoximation system, there are three main silica sources, which are residual silica on the catalyst particles surface during preparation, silica dissolved from TS-1 catalyst particles by ammonia solvent, and silica sol added into the reaction slurry to inhibit the dissolution erosion of the TS-1 catalyst. The silica dissolved by ammonia has been proved to influence membrane fouling most among the three silica sources. This was because the amount of silica dissolved by ammonia was the largest, and the polymerization of silica monomers at high concentration caused colloid particles formation, which led to a dense cake layer depositing on the membrane surface. Meanwhile, the size reduction of catalyst particles caused by alkaline dissolution also increased specific resistances of cake layers.
文摘AIM: To evaluate disease-specific quality of life (QOL) in liver cirrhosis patients and to compare it with those of a healthy population. Also an important objective was to assess whether QOL in liver cirrhosis patients differs by age and gender, by type and severity of disease. METHODS: The case group of 131 liver cirrhosis patients was selected. The control group of 262 was enrolled from a healthy population according to the scheme of case-control study. Clinical, demographic, laboratory data were collected. QOL was measured with a specific chronic liver disease questionnaire (CLDQ), which was translated and validated in Lithuanian. QOL scores were compared between groups by age, gender, type and severity of disease. Cronbach’s alpha statistics calculation was used for evaluation of internal consistency reliability. Student’s t test or ANOVA were used for evaluation hypothesis about probability equation. RESULTS: QOL was significantly lower in liver cirrhosis patients than in healthy population (59.5 ± 18.3 vs 85.3 ± 12.3, P < 0.001). The significant QOL differences between case and control groups were observed in domains of worry and abdominal symptoms, the smaller differences-in emotional functions and systematic symptom domains. Significantly worse QOL was in observed patients with increased clinical severity of the disease measured by Child-Pugh class. Age, gender and etiology of disease had an insignificant effect on QOL in cirrhotic patients. CONCLUSION: QOL was significantly impaired in all CLDQ domains in liver cirrhosis patients. Increase in severity of disease was the major factor associated with poorer QOL.
