A centrifugal fan with the high speed and compact dimensions is studied numerically and experimentally. The centrifugal fan consists of a shrouded impeller rotating at 34 000 r/min with a small tip clearance 0.7 mm to...A centrifugal fan with the high speed and compact dimensions is studied numerically and experimentally. The centrifugal fan consists of a shrouded impeller rotating at 34 000 r/min with a small tip clearance 0.7 mm to the fixed outer casing. Computational models with/without the tip clearance are built and the κ-ω shear stress transport （SST） turbulence model and the unstructured mesh are applied to the numerical simulation for unsteady solutions. The overall performance is measured on a standard experimental bench and the major flow feature of each component inside the centrifugal fan is numerically investigated. In the presence of the tip clearance due to the difference of static pressure between leading and trailing edges of the clearance, i. e. , leading and trailing edges of the impeller, a strong return flow exists inside the clearance passage and re-circulates the main stream inside the impeller passage, and produces the strong flow interaction, thus changing the flow field and influencing the overall performance.展开更多
The spores of Ganoderma lucidum were ground and broken to ultrafine particles by high speed centrifugal shearing（HSCS） pulverizer. The characteristics of Ganoderma lucidum spores were analyzed by scanning electron m...The spores of Ganoderma lucidum were ground and broken to ultrafine particles by high speed centrifugal shearing（HSCS） pulverizer. The characteristics of Ganoderma lucidum spores were analyzed by scanning electron microscope （SEM）, Fourier transform infrared spectrophotometry （FTIR）. Ultraviolet-visible pectrophotometer was used to determine the extraction ratio of aqueous solubility polysaccharide between the raw and broken spores. The immunological function on the mice before and after the breaking of spores wan investigated. The experimental results show that after being ground, the sporoderm-broken ratio reachs 100%, the original active ingredients of ganoderma lucidum spores do not change, and the extraction ratio of aqueous solubility polysaccharide is greatly increased by 40.08%. The broken spores show much higher immunological activity comparing with original spores of Ganoderma lucidum.展开更多
Objective To develop an efficient method for separating and purifying puerarin from the roots of Pueraria lobata.Methods Separation by fast centrifugal partition chromatography（FCPC）was processed with a biphasic sol...Objective To develop an efficient method for separating and purifying puerarin from the roots of Pueraria lobata.Methods Separation by fast centrifugal partition chromatography（FCPC）was processed with a biphasic solvent system composed of ethyl acetate-n-butanol-water（2：1：3）.The separation conditions were determined as follows：sample loading of 10 mg,flow rate of 2 mL/min,rotation speed of 2200 r/min,ascending mode,and detection wavelength of 254 nm.High speed countercurrent chromatography（HSCCC）was used as a comparative method with the rotation speed of 800 r/min,flow rate of 2.0 mL/min,and sample loading of 10 mg in tail-to-head mode.Results Puerarin was obtained by FCPC with a resolution of 0.90 and a purity above 99%,while a resolution below 0.50 and a purity below 90%by HSCCC.Compared with HSCCC,FCPC has the advantages with higher purity and better resolution.Conclusion FCPC is a powerful method to separate and purify puerarin.展开更多
文摘A centrifugal fan with the high speed and compact dimensions is studied numerically and experimentally. The centrifugal fan consists of a shrouded impeller rotating at 34 000 r/min with a small tip clearance 0.7 mm to the fixed outer casing. Computational models with/without the tip clearance are built and the κ-ω shear stress transport （SST） turbulence model and the unstructured mesh are applied to the numerical simulation for unsteady solutions. The overall performance is measured on a standard experimental bench and the major flow feature of each component inside the centrifugal fan is numerically investigated. In the presence of the tip clearance due to the difference of static pressure between leading and trailing edges of the clearance, i. e. , leading and trailing edges of the impeller, a strong return flow exists inside the clearance passage and re-circulates the main stream inside the impeller passage, and produces the strong flow interaction, thus changing the flow field and influencing the overall performance.
基金the National Natural Science Foundation of China(No.50272047)Ministry of Education of China(No.704034)
文摘The spores of Ganoderma lucidum were ground and broken to ultrafine particles by high speed centrifugal shearing（HSCS） pulverizer. The characteristics of Ganoderma lucidum spores were analyzed by scanning electron microscope （SEM）, Fourier transform infrared spectrophotometry （FTIR）. Ultraviolet-visible pectrophotometer was used to determine the extraction ratio of aqueous solubility polysaccharide between the raw and broken spores. The immunological function on the mice before and after the breaking of spores wan investigated. The experimental results show that after being ground, the sporoderm-broken ratio reachs 100%, the original active ingredients of ganoderma lucidum spores do not change, and the extraction ratio of aqueous solubility polysaccharide is greatly increased by 40.08%. The broken spores show much higher immunological activity comparing with original spores of Ganoderma lucidum.
基金International Science and Technology cooperation project of Shanghai(No.12120701400,2012)
文摘Objective To develop an efficient method for separating and purifying puerarin from the roots of Pueraria lobata.Methods Separation by fast centrifugal partition chromatography（FCPC）was processed with a biphasic solvent system composed of ethyl acetate-n-butanol-water（2：1：3）.The separation conditions were determined as follows：sample loading of 10 mg,flow rate of 2 mL/min,rotation speed of 2200 r/min,ascending mode,and detection wavelength of 254 nm.High speed countercurrent chromatography（HSCCC）was used as a comparative method with the rotation speed of 800 r/min,flow rate of 2.0 mL/min,and sample loading of 10 mg in tail-to-head mode.Results Puerarin was obtained by FCPC with a resolution of 0.90 and a purity above 99%,while a resolution below 0.50 and a purity below 90%by HSCCC.Compared with HSCCC,FCPC has the advantages with higher purity and better resolution.Conclusion FCPC is a powerful method to separate and purify puerarin.
