通过北京市34个国控监测站点,建立0.5、1、1.5、2、3、4、5km的缓冲区,应用土地利用回归模型(Land Use Regression,LUR)对北京市采暖季与非采暖季PM_(2.5)浓度进行空间分布模拟,并采用留一交叉互验法验证模型精度。结果表明:采暖季LUR...通过北京市34个国控监测站点,建立0.5、1、1.5、2、3、4、5km的缓冲区,应用土地利用回归模型(Land Use Regression,LUR)对北京市采暖季与非采暖季PM_(2.5)浓度进行空间分布模拟,并采用留一交叉互验法验证模型精度。结果表明:采暖季LUR模型调整R^(2)为0.799,模拟精度为0.7992,均方根误差(Root Mean Square Error,RMSE)为6.66μg·m^(-3);非采暖季LUR模型调整R^(2)为0.807,模拟精度为0.8198,均方根误差为5.91μg·m^(-3),模型表现良好。从模拟结果来看,北京市PM_(2.5)主要分布在东南部人口、交通密集的平原区域,整体呈现南高北低的状态。展开更多
[Objective] The paper was to observe the clinical effects of compound Chinese traditional preparation Shenwudi oral liquid on prevention and treatment of piglet diarrhea, and to explore the diarrhea prevention and gro...[Objective] The paper was to observe the clinical effects of compound Chinese traditional preparation Shenwudi oral liquid on prevention and treatment of piglet diarrhea, and to explore the diarrhea prevention and growth promotion effect of Shenwudi power on weaned piglets as the medical feed additive. [Method] Diarrhea piglets were randomly grouped, and the clinical prevention and treatment effects of Shenwudi oral liquid were observed. Meantime, the effects of Huangzhi oral liquid and levofloxacin mesylate and sodium chloride injection were determined and compared with that of Shenwudi oral liquid. Shenwudi powder was added into the specific feed of weaned piglets at the dose of 5 g/kg, to observe its diarrhea prevention and growth promotion effect on weaned piglets. Compound amoxicillin powder was added in drug control group at the dose of 0.3 g/kg; no drug was added in blank control group. [Result] The cure rate of sucking piglets by Shenwudi oral liquid was 88.57%, and its protection rate was 100%; the cure rate of weaned piglets by Shenwudi oral liquid was 90.00%, and the total effective rate was 95.00%; the protection rate of weaned piglet diarrhea by Shenwudi powder mixing feed was 100%, and the average daily feed intake on the 42^（nd） day was extremely higher than the blank control group（P〈0.01）. [Conclusion] Shenwudi oral liquid can be used for prevention and treatment of sucking piglet diarrhea.Meantime, Shenwudi mixing feed has good prevention effect and significant growth promotion effect on weaned piglet diarrhea.展开更多
According to the time&space conversion relations and different frequency phase detection principle,an ultra-high precision time&frequency measurement method is proposed in this paper.The higher accuracy and st...According to the time&space conversion relations and different frequency phase detection principle,an ultra-high precision time&frequency measurement method is proposed in this paper.The higher accuracy and stability of the speed of light and electromagnetic signals during the transmission in space or a specific medium enable the measurement of short time interval which uses the coincidence detection of signal’s transmission delay in length.The measurement precision better than 10 picoseconds can be easily obtained.The method develops the length vernier utilizing the stability of signal’s transmission delay,minimizes the fuzzy region of phase coincidence between the standard frequency signal and the measured signal,approaches the best phase coincidences and therefore improves the measurement precision which is higher than the precision provided by the traditional methods based on frequency processing.Besides,the method costs less than the traditional methods and can also solve the problem of the measurement of super-high frequency.Experimental results show the method can improve the measurement precision to 10 12/s in the time&frequency domain.展开更多
The phase group synchronization between any signals is further revealed,which is based on proposing the new concepts of the greatest common factor frequency,the least common multiple period,quantized phase shift resol...The phase group synchronization between any signals is further revealed,which is based on proposing the new concepts of the greatest common factor frequency,the least common multiple period,quantized phase shift resolution,equivalent phase comparison frequency and so on.Then the problem of phase comparison and processing between different frequency signals is solved and shown in detail.Using the basic principle and the variation law of group phase difference,the frequency stability better than 10-14/s can be easily obtained in the time&frequency measurement and control domain,and experimental results also show the phase relations between atomic energy level transition signal and the locked crystal oscillator signal in an active hydrogen atomic clock are strict phase group synchronization,and locked precision with 10-13/s can be reached based on phase group synchronization.The phase group synchronization can provide technical support to frequency linking among radio frequency,microwave and light frequency.展开更多
文摘通过北京市34个国控监测站点,建立0.5、1、1.5、2、3、4、5km的缓冲区,应用土地利用回归模型(Land Use Regression,LUR)对北京市采暖季与非采暖季PM_(2.5)浓度进行空间分布模拟,并采用留一交叉互验法验证模型精度。结果表明:采暖季LUR模型调整R^(2)为0.799,模拟精度为0.7992,均方根误差(Root Mean Square Error,RMSE)为6.66μg·m^(-3);非采暖季LUR模型调整R^(2)为0.807,模拟精度为0.8198,均方根误差为5.91μg·m^(-3),模型表现良好。从模拟结果来看,北京市PM_(2.5)主要分布在东南部人口、交通密集的平原区域,整体呈现南高北低的状态。
基金Supported by Science and Technology Innovation Project of Gansu Province(GNCX-2014-1)
文摘[Objective] The paper was to observe the clinical effects of compound Chinese traditional preparation Shenwudi oral liquid on prevention and treatment of piglet diarrhea, and to explore the diarrhea prevention and growth promotion effect of Shenwudi power on weaned piglets as the medical feed additive. [Method] Diarrhea piglets were randomly grouped, and the clinical prevention and treatment effects of Shenwudi oral liquid were observed. Meantime, the effects of Huangzhi oral liquid and levofloxacin mesylate and sodium chloride injection were determined and compared with that of Shenwudi oral liquid. Shenwudi powder was added into the specific feed of weaned piglets at the dose of 5 g/kg, to observe its diarrhea prevention and growth promotion effect on weaned piglets. Compound amoxicillin powder was added in drug control group at the dose of 0.3 g/kg; no drug was added in blank control group. [Result] The cure rate of sucking piglets by Shenwudi oral liquid was 88.57%, and its protection rate was 100%; the cure rate of weaned piglets by Shenwudi oral liquid was 90.00%, and the total effective rate was 95.00%; the protection rate of weaned piglet diarrhea by Shenwudi powder mixing feed was 100%, and the average daily feed intake on the 42^（nd） day was extremely higher than the blank control group（P〈0.01）. [Conclusion] Shenwudi oral liquid can be used for prevention and treatment of sucking piglet diarrhea.Meantime, Shenwudi mixing feed has good prevention effect and significant growth promotion effect on weaned piglet diarrhea.
基金supported by the National Natural Science Foundation of China (Grant No. U1304618)the Open Fund of Key Laboratory of Precision Navigation and Timing Technology of Chinese Academy of Sciences(Grant No. 2012PNTT01)+5 种基金the Postdoctoral Grant of China (Grant Nos. 2011M501446, 2012T50798)the Basic and Advanced Technology Research Foundation of Henan Province under Grant (Grant No. 122300410169)The Key Science and Technology Foundation of Henan Province under Grant (Grant No. 132102210180)the Doctor Fund of Zhengzhou University of Light Industry under (Grant No. 2011BSJJ031)the Scientific Research Fund of Zhengzhou University of Light Industry under (Grant No. 2012XJJ009)the Fundamental Research Funds for the Central Universities(Grant No. K5051204003)
文摘According to the time&space conversion relations and different frequency phase detection principle,an ultra-high precision time&frequency measurement method is proposed in this paper.The higher accuracy and stability of the speed of light and electromagnetic signals during the transmission in space or a specific medium enable the measurement of short time interval which uses the coincidence detection of signal’s transmission delay in length.The measurement precision better than 10 picoseconds can be easily obtained.The method develops the length vernier utilizing the stability of signal’s transmission delay,minimizes the fuzzy region of phase coincidence between the standard frequency signal and the measured signal,approaches the best phase coincidences and therefore improves the measurement precision which is higher than the precision provided by the traditional methods based on frequency processing.Besides,the method costs less than the traditional methods and can also solve the problem of the measurement of super-high frequency.Experimental results show the method can improve the measurement precision to 10 12/s in the time&frequency domain.
基金supported by the Joint Fund for Fostering Talents of National Natural Science Foundation of China and Henan Province(Grant No.U1304618)the Open Fund of Key Laboratory of Precision Navigation and Timing Technology of Chinese Academy of Sciences(Grant No.2012PNTT01)+4 种基金the Postdoctoral Grant of China(Grant Nos.2011M501446,2012T50798)the Basic and Advanced Technology Research Foundation of Henan Province(Grant No.122300410169)The Key Science and Technology Foundation of Zhengzhou City(Grant Nos.131PPTGG411-6,131PCXTD594)the Doctor Fund of Zhengzhou University of Light Industry(Grant No.2011BSJJ031)the Fundamental Research Funds for the Central Universities(Grant No.K5051204003)
文摘The phase group synchronization between any signals is further revealed,which is based on proposing the new concepts of the greatest common factor frequency,the least common multiple period,quantized phase shift resolution,equivalent phase comparison frequency and so on.Then the problem of phase comparison and processing between different frequency signals is solved and shown in detail.Using the basic principle and the variation law of group phase difference,the frequency stability better than 10-14/s can be easily obtained in the time&frequency measurement and control domain,and experimental results also show the phase relations between atomic energy level transition signal and the locked crystal oscillator signal in an active hydrogen atomic clock are strict phase group synchronization,and locked precision with 10-13/s can be reached based on phase group synchronization.The phase group synchronization can provide technical support to frequency linking among radio frequency,microwave and light frequency.
