The scaling process of calcium carbonate on a low-energy heat transfer surface－electroless plating surface was investigated in a simulated cooling water system. Owing to the very low surface energy, the electroless p...The scaling process of calcium carbonate on a low-energy heat transfer surface－electroless plating surface was investigated in a simulated cooling water system. Owing to the very low surface energy, the electroless plating surface exhibited less scaling susceptibility. A longer induction period and a lower scaling rate were obtained on the low-energy surface compared to copper surface under identical conditions. The calcite particles obtained on the electroless plating surface during the induction period were larger in size than those on copper surface because fewer crystals formed and grew at the same time on the low-energy surface. With increasing surface temperature, the induction period reduced and the scaling rate increased for the low-energy surface. When initial surface temperature was fixed, an increase in fluid velocity would reduce the induction period and increase the scaling rate due to the diffusion effect. However, when the heat flux was fixed, an increase in fluid velocity would decrease the surfacetemperature, and lead to a longer induction period and a lower scaling rate. The removal experiments of calcium carbonate scale indicated that during post induction period, the detachment was not obvious, while during the induction period, apparent removal of crystal particles was obtained on the electroless plating surface owing to the weak adhesion force. The more frequently the transient high hydrodynamic force acted, the more the detached crystal particles were.展开更多
A new procedure of determining optimal C/N (the rate of carbon source to nitrogen source) of mixed distillers' grains for combined bacteria synergic fermentation is established. At the same time an improved method...A new procedure of determining optimal C/N (the rate of carbon source to nitrogen source) of mixed distillers' grains for combined bacteria synergic fermentation is established. At the same time an improved method evaluating bacteria growth, called method of dry cell weighing by filtering is developed. For each combination of C and N, their initial and residual contents before and after fermentation respectively are determined. Then followed the calculation of utilization of C and N sources by the compound bacteria. The optimal C/N is finally located from among the utilization of C and N of several combinations and the weight of produced mass of oven dried thallus. The conditions of fermentation are: inoculum size 10%, temperature 30 0℃, rotational speed 170 r/min, shake culture time 48h. The best results obtained from orthogonal experiments are: maximum mass of oven dried thallus is 14 693g in a liter liquid medium, maximum utilization rate of carbon source is 98 13% and maximum utilization rate of nitrogen is 78 14%. Optimal C/N is 5 1.展开更多
The reactive precipitation process of procaine benzylpenicillin is reviewed, while such secondary processes as ageing, agglomeration, breakage, and the effects of operation parameters on crystal size are emphasized. I...The reactive precipitation process of procaine benzylpenicillin is reviewed, while such secondary processes as ageing, agglomeration, breakage, and the effects of operation parameters on crystal size are emphasized. In the reactive precipitation the ageing of particles has a little effect on the process, while the greater effect comes from the agglomeration and breakage of particles, furthermore, the mixing has also notable influence on the product size. All of these provide the bases for further study on reactive precipitation.展开更多
Excellent dropwise condensation of steam was observed on a polytethefluoroethylene (PTFE) coated plate. The experimental results indicated that the condensation heat transfer performance was increased by 30 to 47 time...Excellent dropwise condensation of steam was observed on a polytethefluoroethylene (PTFE) coated plate. The experimental results indicated that the condensation heat transfer performance was increased by 30 to 47 times when compared with film condensation values at the same surface subcooling degrees. The random fluctuation of the surface temperature was resulted from the high thermal conductivity of the copper substrate and the ultra thin coated polymer film with lower surface free energy. The effect of the steam temperature for pressures near atmospheric pressure on the dropwise condensation heat transfer characteristics was investigated as well.展开更多
基金the National Natural Science Foundation of China (No. 29776008)
文摘The scaling process of calcium carbonate on a low-energy heat transfer surface－electroless plating surface was investigated in a simulated cooling water system. Owing to the very low surface energy, the electroless plating surface exhibited less scaling susceptibility. A longer induction period and a lower scaling rate were obtained on the low-energy surface compared to copper surface under identical conditions. The calcite particles obtained on the electroless plating surface during the induction period were larger in size than those on copper surface because fewer crystals formed and grew at the same time on the low-energy surface. With increasing surface temperature, the induction period reduced and the scaling rate increased for the low-energy surface. When initial surface temperature was fixed, an increase in fluid velocity would reduce the induction period and increase the scaling rate due to the diffusion effect. However, when the heat flux was fixed, an increase in fluid velocity would decrease the surfacetemperature, and lead to a longer induction period and a lower scaling rate. The removal experiments of calcium carbonate scale indicated that during post induction period, the detachment was not obvious, while during the induction period, apparent removal of crystal particles was obtained on the electroless plating surface owing to the weak adhesion force. The more frequently the transient high hydrodynamic force acted, the more the detached crystal particles were.
文摘A new procedure of determining optimal C/N (the rate of carbon source to nitrogen source) of mixed distillers' grains for combined bacteria synergic fermentation is established. At the same time an improved method evaluating bacteria growth, called method of dry cell weighing by filtering is developed. For each combination of C and N, their initial and residual contents before and after fermentation respectively are determined. Then followed the calculation of utilization of C and N sources by the compound bacteria. The optimal C/N is finally located from among the utilization of C and N of several combinations and the weight of produced mass of oven dried thallus. The conditions of fermentation are: inoculum size 10%, temperature 30 0℃, rotational speed 170 r/min, shake culture time 48h. The best results obtained from orthogonal experiments are: maximum mass of oven dried thallus is 14 693g in a liter liquid medium, maximum utilization rate of carbon source is 98 13% and maximum utilization rate of nitrogen is 78 14%. Optimal C/N is 5 1.
文摘The reactive precipitation process of procaine benzylpenicillin is reviewed, while such secondary processes as ageing, agglomeration, breakage, and the effects of operation parameters on crystal size are emphasized. In the reactive precipitation the ageing of particles has a little effect on the process, while the greater effect comes from the agglomeration and breakage of particles, furthermore, the mixing has also notable influence on the product size. All of these provide the bases for further study on reactive precipitation.
基金the Nahonal NaedScience Foundation of China (No.599060()2) and the Scienhficresereh FOundahon for the Retwed Oversea Chinese
文摘Excellent dropwise condensation of steam was observed on a polytethefluoroethylene (PTFE) coated plate. The experimental results indicated that the condensation heat transfer performance was increased by 30 to 47 times when compared with film condensation values at the same surface subcooling degrees. The random fluctuation of the surface temperature was resulted from the high thermal conductivity of the copper substrate and the ultra thin coated polymer film with lower surface free energy. The effect of the steam temperature for pressures near atmospheric pressure on the dropwise condensation heat transfer characteristics was investigated as well.
