Extracellular xylanase XYNB from Streptomy-ces olivaceoviridis A1 has been purified and characterized. The optimal pH value and temperature of XYNB for its ac-tivity are 5.2 and 60℃, respectively. The specific activi...Extracellular xylanase XYNB from Streptomy-ces olivaceoviridis A1 has been purified and characterized. The optimal pH value and temperature of XYNB for its ac-tivity are 5.2 and 60℃, respectively. The specific activity of XYNB is as high as 2869.78 U/mg. Metal cations, EDTA and SDS have no effects on enzyme activity of XYNB. The gene xynB coding mature protein of XYNB has been cloned by PCR. The forward oligonucleotide primer used in the PCR reaction was synthesized based on the N-terminal amino acid sequence of XYNB mature protein, and the reverse oligonu-cleotide primers are random oligonucleotide. The cloned gene xynB is 576 bp long and its G+C content is 64.3%. The xynB encodes 191 amino acid residues, and the putative mo-lecular weight of XYNB is 20.839 kD. The xynB has been expressed in E. coli, and the expressed xylanase has normal bioactivity.展开更多
Optical coherence microscopy is applied to measure scattering media'sinternal defect, which based on low coherence interferometry and confocal microscopy. Opticalcoherence microscopy is more effective in the rejec...Optical coherence microscopy is applied to measure scattering media'sinternal defect, which based on low coherence interferometry and confocal microscopy. Opticalcoherence microscopy is more effective in the rejection of out of focus and multiple scatteredphotons originating further away of the focal plane. With the three-dimension scanning, the internaldefect is detected by measuring the thickness of different points on the sample. The axialresolution is 6 μm and lateral resolution is 1. 2 μm. This method is possessed of the advantagesover the other measurement method of scattering media, such as non-destruction and high-resolution.展开更多
A whole-field 3D surface measurement system for semiconductor wafer inspection is described.The system consists of an optical fiber plate,which can split the light beam into N^2 subbeams to realize the whole-field ins...A whole-field 3D surface measurement system for semiconductor wafer inspection is described.The system consists of an optical fiber plate,which can split the light beam into N^2 subbeams to realize the whole-field inspection.A special prism is used to separate the illumination light and signal light.This setup is characterized by high precision,high speed and simple structure.展开更多
Background Ageing is associated with increased incidence of dyslipidemia. Toinvestigate potential molecular mechanisms, the effects of age and fibrate administration onperoxisome proliferator-activated receptor α (P...Background Ageing is associated with increased incidence of dyslipidemia. Toinvestigate potential molecular mechanisms, the effects of age and fibrate administration onperoxisome proliferator-activated receptor α (PPARα) expression in livers of young and old ratswere studied. Methods A total of 16 young (2-month-old) and 16 old rats (24-month-old) were randomlyassigned to a control group and fenofibrate group (fenofibrate in a total therapeutic dosage of 0.5% in ratio to each treated rat weight in 14 days). RT-PCR was applied to evaluate hepatic mRNAexpression of PPARα and its target genes. Western blotting was used to determine PPARα proteinlevel in liver tissue. Results When compared with 2-month-old rats, the liver tissue from24-month-old rats showed reduced expression of PPARα mRNA (52% , P <0. 05) and protein (109% , P <0. 01). Consequently, the mRNA levels of PPAR target genes, LPL, ACO, ACS and CPT-1 were markedlylowered by 19% , 8% , 13% and 9% respectively, and apoCⅢ increased by 24% in livers from24-month-old rats, compared with values obtained from 2-month-old rats ( P < 0. 05 ) . Fenofibratetherapy significantly lowered plasma triglyceride and total cholesterol levels in old rats,accompanied with improvement in hepatic expression of genes, including LPL, ACO, ACS, CPT-1 andapoCⅢ, but no change was found in PPARα expression in livers from either 24-month or 2-month-oldrats. Conclusions The decrease in the hepatic PPARα expression is probably directly related to thelipid metabolic disturbances observed in old animals. The beneficial effects of fenofibrateadministration in old rats suggests that fibrates may be useful for treating lipid disturbances inold people.展开更多
In order to improve the control precision of strip coiling temperature for hot strip mill,the BP neural network was combined with mathematical model to calculate convective heat-transfer coefficient of laminar flow co...In order to improve the control precision of strip coiling temperature for hot strip mill,the BP neural network was combined with mathematical model to calculate convective heat-transfer coefficient of laminar flow cooling.The off-line calculated results indicate that the standard deviation of coiling temperature prediction is reduced by 22.84 % with the convective heat-transfer coefficient calculated by BP neural network.The prospects of this method for online application are bright.This method is more helpful to increasing the control precision of coiling temperature for hot strip steel.展开更多
As wave propagates into shallow water, the shoaling effect leads to increaseof wave height, and at a certain position, the wave will be breaking. The breaking wave is powerfulagents for generating turbulence, which pl...As wave propagates into shallow water, the shoaling effect leads to increaseof wave height, and at a certain position, the wave will be breaking. The breaking wave is powerfulagents for generating turbulence, which plays an important role in most of the fluid dynamicalprocesses in the surf zone, so a proper numerical model for describing the turbulent effect isneeded urgently. A numerical model is set up to simulate the wave breaking process, which consistsof a free surface model using the surface marker method and the vertical two-dimensional model thatsolves the flow equations. The turbulence is described by Large Eddy Simulation (LES) method wherethe larger turbulent features are simulated by solving the flow equations, and the small-scaleturbulence that is represented by a sub-grid model. A dynamic eddy viscosity sub-grid scale stressmodel has been used for the present simulation. The large eddy simulation model, which we presentedin this paper, can be used to study the propagation of a solitary wave in constant water depth andthe shoaling of a non-breaking solitary wave on a beach. To track free-surface movements, The TUMMACmethod is employed. By applying the model to wave breaking problem in the surf zone, we found thatthese model results compared very well with experimental data. In addition, this model is able toreproduce the complicated flow phenomena, especially the plunging breaker.展开更多
基金This work was supported by the State"863"High-Tech Programs(Grant No.2001AA214041).
文摘Extracellular xylanase XYNB from Streptomy-ces olivaceoviridis A1 has been purified and characterized. The optimal pH value and temperature of XYNB for its ac-tivity are 5.2 and 60℃, respectively. The specific activity of XYNB is as high as 2869.78 U/mg. Metal cations, EDTA and SDS have no effects on enzyme activity of XYNB. The gene xynB coding mature protein of XYNB has been cloned by PCR. The forward oligonucleotide primer used in the PCR reaction was synthesized based on the N-terminal amino acid sequence of XYNB mature protein, and the reverse oligonu-cleotide primers are random oligonucleotide. The cloned gene xynB is 576 bp long and its G+C content is 64.3%. The xynB encodes 191 amino acid residues, and the putative mo-lecular weight of XYNB is 20.839 kD. The xynB has been expressed in E. coli, and the expressed xylanase has normal bioactivity.
基金National Natural Science Foundation of China(60077031)
文摘Optical coherence microscopy is applied to measure scattering media'sinternal defect, which based on low coherence interferometry and confocal microscopy. Opticalcoherence microscopy is more effective in the rejection of out of focus and multiple scatteredphotons originating further away of the focal plane. With the three-dimension scanning, the internaldefect is detected by measuring the thickness of different points on the sample. The axialresolution is 6 μm and lateral resolution is 1. 2 μm. This method is possessed of the advantagesover the other measurement method of scattering media, such as non-destruction and high-resolution.
文摘A whole-field 3D surface measurement system for semiconductor wafer inspection is described.The system consists of an optical fiber plate,which can split the light beam into N^2 subbeams to realize the whole-field inspection.A special prism is used to separate the illumination light and signal light.This setup is characterized by high precision,high speed and simple structure.
文摘Background Ageing is associated with increased incidence of dyslipidemia. Toinvestigate potential molecular mechanisms, the effects of age and fibrate administration onperoxisome proliferator-activated receptor α (PPARα) expression in livers of young and old ratswere studied. Methods A total of 16 young (2-month-old) and 16 old rats (24-month-old) were randomlyassigned to a control group and fenofibrate group (fenofibrate in a total therapeutic dosage of 0.5% in ratio to each treated rat weight in 14 days). RT-PCR was applied to evaluate hepatic mRNAexpression of PPARα and its target genes. Western blotting was used to determine PPARα proteinlevel in liver tissue. Results When compared with 2-month-old rats, the liver tissue from24-month-old rats showed reduced expression of PPARα mRNA (52% , P <0. 05) and protein (109% , P <0. 01). Consequently, the mRNA levels of PPAR target genes, LPL, ACO, ACS and CPT-1 were markedlylowered by 19% , 8% , 13% and 9% respectively, and apoCⅢ increased by 24% in livers from24-month-old rats, compared with values obtained from 2-month-old rats ( P < 0. 05 ) . Fenofibratetherapy significantly lowered plasma triglyceride and total cholesterol levels in old rats,accompanied with improvement in hepatic expression of genes, including LPL, ACO, ACS, CPT-1 andapoCⅢ, but no change was found in PPARα expression in livers from either 24-month or 2-month-oldrats. Conclusions The decrease in the hepatic PPARα expression is probably directly related to thelipid metabolic disturbances observed in old animals. The beneficial effects of fenofibrateadministration in old rats suggests that fibrates may be useful for treating lipid disturbances inold people.
基金Item Sponsored by National Natural Science Foundation of China(50104004)
文摘In order to improve the control precision of strip coiling temperature for hot strip mill,the BP neural network was combined with mathematical model to calculate convective heat-transfer coefficient of laminar flow cooling.The off-line calculated results indicate that the standard deviation of coiling temperature prediction is reduced by 22.84 % with the convective heat-transfer coefficient calculated by BP neural network.The prospects of this method for online application are bright.This method is more helpful to increasing the control precision of coiling temperature for hot strip steel.
文摘As wave propagates into shallow water, the shoaling effect leads to increaseof wave height, and at a certain position, the wave will be breaking. The breaking wave is powerfulagents for generating turbulence, which plays an important role in most of the fluid dynamicalprocesses in the surf zone, so a proper numerical model for describing the turbulent effect isneeded urgently. A numerical model is set up to simulate the wave breaking process, which consistsof a free surface model using the surface marker method and the vertical two-dimensional model thatsolves the flow equations. The turbulence is described by Large Eddy Simulation (LES) method wherethe larger turbulent features are simulated by solving the flow equations, and the small-scaleturbulence that is represented by a sub-grid model. A dynamic eddy viscosity sub-grid scale stressmodel has been used for the present simulation. The large eddy simulation model, which we presentedin this paper, can be used to study the propagation of a solitary wave in constant water depth andthe shoaling of a non-breaking solitary wave on a beach. To track free-surface movements, The TUMMACmethod is employed. By applying the model to wave breaking problem in the surf zone, we found thatthese model results compared very well with experimental data. In addition, this model is able toreproduce the complicated flow phenomena, especially the plunging breaker.
