Feeding rhythm of common carp was investigated from 4℃ to 34℃. The results indicated that there was a diel feeding rhythm for both adult （630-850 g） and youth （61-91 g） at all tested temperatures. There were two...Feeding rhythm of common carp was investigated from 4℃ to 34℃. The results indicated that there was a diel feeding rhythm for both adult （630-850 g） and youth （61-91 g） at all tested temperatures. There were two main activity peaks at 8：00-11：00 a.m. and 19：00-23：00 p.m., during which feeding quantities were 10.68%-32.53% and 16.25%-33.41% of the daily intake, respectively. When water temperature dropped to below 10℃, the feeding peak concentrated at 8：00-11：00 a.m. and 19：00 p.m. to 4：00 a.m. At 6℃, though both adult and youth would still feed, the feeding quantities were only 0.01% and 0.35% of body mass. Daily feeding rate of adult and youth reached 1.21% and 2.63% at 14℃, respectively. Both adult and youth carps reached the maximum daily feeding rate at 28℃, being 2.84% and 12.06% of body mass, respectively. The daily feeding rate of adult and youth reduced suddenly after at 34℃, and the daily feeding rate was only 0.74% and 9.45% of body mass, respectively. There was significant difference in daily feeding rate at different water temperatures （P〈0.05）.展开更多
[Objective] The research aimed to study the determination of 16 kinds of OCPs in water by liquid-liquid extraction -GC. [Method] The new method for determining 16 kinds of OCPs in water by liquid-liquid extraction -GC...[Objective] The research aimed to study the determination of 16 kinds of OCPs in water by liquid-liquid extraction -GC. [Method] The new method for determining 16 kinds of OCPs in water by liquid-liquid extraction -GC was established, and the influencing factors such as nitrogen pressure and water bath temperature were discussed. [ Result] Detection limit of the method was from 3.2 to 14.1 ng/L, the relative standard deviation was between 4.0% and 9.6%, and the average recovery ranged from 80.8% to 106.0%. By optimizing nitrogen pressure and water bath temperature in the sample pretreatment process, when nitrogen pressure was ＋0.087 kPa, and water bath temperature was ±36 ℃, recovery effect of this method was better. [ Conclusion] The determination method had accurate qualitative and quantitative results, and met detection requirement of 16 kinds of OCPs in water.展开更多
The stable operation of the central air conditioning water system always is a major difficulty for the control profession. Paper focus on the water system with multi variable, strong coupling, nonlinear, large time de...The stable operation of the central air conditioning water system always is a major difficulty for the control profession. Paper focus on the water system with multi variable, strong coupling, nonlinear, large time delay characteristics, presented use feed forward coupling compensation method, to eliminate the coupling effect between temperature and pressure. In this paper, the Elman neural network controller is designed for the first time, and the simulation results show that the response time of Elman neural network controller is shorter, the system is more stable and the overshoot is small.展开更多
文摘Feeding rhythm of common carp was investigated from 4℃ to 34℃. The results indicated that there was a diel feeding rhythm for both adult （630-850 g） and youth （61-91 g） at all tested temperatures. There were two main activity peaks at 8：00-11：00 a.m. and 19：00-23：00 p.m., during which feeding quantities were 10.68%-32.53% and 16.25%-33.41% of the daily intake, respectively. When water temperature dropped to below 10℃, the feeding peak concentrated at 8：00-11：00 a.m. and 19：00 p.m. to 4：00 a.m. At 6℃, though both adult and youth would still feed, the feeding quantities were only 0.01% and 0.35% of body mass. Daily feeding rate of adult and youth reached 1.21% and 2.63% at 14℃, respectively. Both adult and youth carps reached the maximum daily feeding rate at 28℃, being 2.84% and 12.06% of body mass, respectively. The daily feeding rate of adult and youth reduced suddenly after at 34℃, and the daily feeding rate was only 0.74% and 9.45% of body mass, respectively. There was significant difference in daily feeding rate at different water temperatures （P〈0.05）.
文摘[Objective] The research aimed to study the determination of 16 kinds of OCPs in water by liquid-liquid extraction -GC. [Method] The new method for determining 16 kinds of OCPs in water by liquid-liquid extraction -GC was established, and the influencing factors such as nitrogen pressure and water bath temperature were discussed. [ Result] Detection limit of the method was from 3.2 to 14.1 ng/L, the relative standard deviation was between 4.0% and 9.6%, and the average recovery ranged from 80.8% to 106.0%. By optimizing nitrogen pressure and water bath temperature in the sample pretreatment process, when nitrogen pressure was ＋0.087 kPa, and water bath temperature was ±36 ℃, recovery effect of this method was better. [ Conclusion] The determination method had accurate qualitative and quantitative results, and met detection requirement of 16 kinds of OCPs in water.
文摘The stable operation of the central air conditioning water system always is a major difficulty for the control profession. Paper focus on the water system with multi variable, strong coupling, nonlinear, large time delay characteristics, presented use feed forward coupling compensation method, to eliminate the coupling effect between temperature and pressure. In this paper, the Elman neural network controller is designed for the first time, and the simulation results show that the response time of Elman neural network controller is shorter, the system is more stable and the overshoot is small.
