Based on the realization of moving-bed cake filtering, the concepts of static-bed filtering time and moving-bed fil- tering time in the helical-conveyor fine coal filtering centrifuge were proposed, and the mathematic...Based on the realization of moving-bed cake filtering, the concepts of static-bed filtering time and moving-bed fil- tering time in the helical-conveyor fine coal filtering centrifuge were proposed, and the mathematic relations between the time defined and the main factors related were studied in detail. The results show that the static-bed filtering time is the function of the spiral heads and the rotation rate deference between the spiral and the porous drum, while the moving-bed filtering time is the function of the cone angle of the porous drum, the radius of the porous drum, the spiral angle, and the rotation rate deference. The functions deduced are of great significance for fine coal filtering centrifuge＇s parameters determining and optimizing. It is shown that the filtering centrifuge with smaller spiral angle, smaller rotation rate deference, and smaller cone angle may do a better job for fine coal dewatering.展开更多
Conventional methods of DNA recovery from agarose gel generally require expensive equipment, extended elution times, or considerable handling of the sample after elution. We developed a simple protocol for a quick and...Conventional methods of DNA recovery from agarose gel generally require expensive equipment, extended elution times, or considerable handling of the sample after elution. We developed a simple protocol for a quick and effective recovery of DNA from agarose gels with good yield and quality. Using a Sephadex resin filled spin column, DNA fragments of 500 bp to 6 kb in an agarose gel slice were easily recovered by a 2 min centrifugation. The recovery efficiencies were over 40% -50% and the eluted DNA can be used directly for downstream application, such as polymerase chain reactions （PCR） and restriction enzyme digestion. This method could also be used to recover large DNA fragment （48 kb） without degradation. The use of Sephadex helps to remove small molecular impurities from agarose and it also reduces the chance of clogging the column filter caused by direct contact with agarose.展开更多
基金Supported by the National Nature Science Foundation of China （51174204）
文摘Based on the realization of moving-bed cake filtering, the concepts of static-bed filtering time and moving-bed fil- tering time in the helical-conveyor fine coal filtering centrifuge were proposed, and the mathematic relations between the time defined and the main factors related were studied in detail. The results show that the static-bed filtering time is the function of the spiral heads and the rotation rate deference between the spiral and the porous drum, while the moving-bed filtering time is the function of the cone angle of the porous drum, the radius of the porous drum, the spiral angle, and the rotation rate deference. The functions deduced are of great significance for fine coal filtering centrifuge＇s parameters determining and optimizing. It is shown that the filtering centrifuge with smaller spiral angle, smaller rotation rate deference, and smaller cone angle may do a better job for fine coal dewatering.
文摘Conventional methods of DNA recovery from agarose gel generally require expensive equipment, extended elution times, or considerable handling of the sample after elution. We developed a simple protocol for a quick and effective recovery of DNA from agarose gels with good yield and quality. Using a Sephadex resin filled spin column, DNA fragments of 500 bp to 6 kb in an agarose gel slice were easily recovered by a 2 min centrifugation. The recovery efficiencies were over 40% -50% and the eluted DNA can be used directly for downstream application, such as polymerase chain reactions （PCR） and restriction enzyme digestion. This method could also be used to recover large DNA fragment （48 kb） without degradation. The use of Sephadex helps to remove small molecular impurities from agarose and it also reduces the chance of clogging the column filter caused by direct contact with agarose.
