High performance liquid chromatographic(HPLC) fingerprints of Cassia seed,a traditional Chinese medicine(TCM),were developed by means of the chromatograms at two wavelengths of 238 and 282 nm.Then,the two data sets we...High performance liquid chromatographic(HPLC) fingerprints of Cassia seed,a traditional Chinese medicine(TCM),were developed by means of the chromatograms at two wavelengths of 238 and 282 nm.Then,the two data sets were combined into one matrix.The application of principal component analysis(PCA) for this data matrix showed that the samples were clustered into four groups in accordance with the plant sources and preparation procedures.Furthermore,partial least squares(PLS),back propagation artificial neural...展开更多
Based on ullstability of inversion algorithms of the lidar equation caused by molecular scattering,a new algorithm to derive both the aerosol extinction to backscatter ratio and the extinchon coefficient profile is pr...Based on ullstability of inversion algorithms of the lidar equation caused by molecular scattering,a new algorithm to derive both the aerosol extinction to backscatter ratio and the extinchon coefficient profile is proposed in this paper.As shown in numerical experiments,in case of a ground-based lidar,the error in the aerosol optical depth solution can be less than 10%,and the error of < 6.7 in the aerosol exhnction to backscatter ratio can be obtained if the error in the lidar constant is<6%;and in the case of a spaceborne lidar,the present method can be ugh to determine the lidar constant at a short wavelength with an accuracy of being better than 1%.展开更多
[Objectives] To establish a determination method for the content of total lignanoids in Tangjiangshenkang granules. [Methods] Two-wavelength ultraviolet spectrophotometry (TWBS) was used to scan arctiin control soluti...[Objectives] To establish a determination method for the content of total lignanoids in Tangjiangshenkang granules. [Methods] Two-wavelength ultraviolet spectrophotometry (TWBS) was used to scan arctiin control solution, chlorogenic acid control solution and Tangjiangshenkang granule test solution in the range of 200-400 nm. In the ultraviolet scanning diagram of arctiin reference solution, the maximum absorption wavelength of 280 nm was determined as the determination wavelength λ 1, the detection wavelength in the ultraviolet scanning diagram of chlorogenic acid reference solution ( λ 1=280 nm) was determined, and 350 nm was the reference wavelength λ 2;the content of total lignosides in Tangjiangshenkang granules was determined with arctiin as the reference substance. [Results] The precision, accuracy, and durability of this method were fine. The concentration of arctiin was linearly correlated with the absorbance difference in the range of 0.007 95-0.071 55 mg/mL ( r =0. 999 9). The average recovery of arctiin was 100.8%, and the RSD value was 1.04% ( n =6). Calculated as arctiin, three batches of Tangjiangshenkang granules contain no less than 20% of total lignosides. [Conclusions] The method has the advantages of simple operation, good accuracy, precision and reliable stability. It can be used as the content determination and quality control method of total lignosides in Tangjiangshenkang granules.展开更多
In this paper,we demonstrate the single-fiber and two-wavelength time transfer(SFTWTT)over a 2061 km field fiber loopback link network with a synchronous wavelength-division and time-division multiplexing access(WD-TD...In this paper,we demonstrate the single-fiber and two-wavelength time transfer(SFTWTT)over a 2061 km field fiber loopback link network with a synchronous wavelength-division and time-division multiplexing access(WD-TDMA).This system utilizes wavelength-division multiplexing to avoid the impact of backscatter.In order to achieve high-precision time transfer,time-division multiplexing access is employed.This approach facilitates multiple bidirectional comparisons between local and remote devices.A digital phase-locked loop(PLL),which matches the bandwidth of the transfer system,and precision temperature control technology have been proposed to enhance the high stability of the fiber-optic time and frequency transfer system.The first on-site high-precision fiber-optic time transfer system exceeding 2000 km has been validated.Experimental results show that the stabilities of 5.6 ps@1 s and 3.1 ps@40,000 s can be achieved.The precision of time transfer over a 2061 km fiber-optic network,employing a single-fiber and two-wavelength approach,has been significantly enhanced.This study presents an average time difference of 52 ps across the distance,with a system uncertainty budgeted at 41.8 ps.This achievement signifies a substantial advancement in the realms of stability and reach for optical fiber time transfer,facilitating the development of a high-precision ground-based time service system.展开更多
基金the financial support for this study by the National Natural Science Foundation of China(No.NSFC20562009)the Jiangxi Province Natural Science Foundation(No.JXNSF0620041)the State Key Laboratory of Food Science and Technology of Nanchang University(Nos.SKLF-MB200807 and SKLF-TS200819)
文摘High performance liquid chromatographic(HPLC) fingerprints of Cassia seed,a traditional Chinese medicine(TCM),were developed by means of the chromatograms at two wavelengths of 238 and 282 nm.Then,the two data sets were combined into one matrix.The application of principal component analysis(PCA) for this data matrix showed that the samples were clustered into four groups in accordance with the plant sources and preparation procedures.Furthermore,partial least squares(PLS),back propagation artificial neural...
文摘Based on ullstability of inversion algorithms of the lidar equation caused by molecular scattering,a new algorithm to derive both the aerosol extinction to backscatter ratio and the extinchon coefficient profile is proposed in this paper.As shown in numerical experiments,in case of a ground-based lidar,the error in the aerosol optical depth solution can be less than 10%,and the error of < 6.7 in the aerosol exhnction to backscatter ratio can be obtained if the error in the lidar constant is<6%;and in the case of a spaceborne lidar,the present method can be ugh to determine the lidar constant at a short wavelength with an accuracy of being better than 1%.
基金Supported by Major Science and Technology Project"Major New Drug Innovation".
文摘[Objectives] To establish a determination method for the content of total lignanoids in Tangjiangshenkang granules. [Methods] Two-wavelength ultraviolet spectrophotometry (TWBS) was used to scan arctiin control solution, chlorogenic acid control solution and Tangjiangshenkang granule test solution in the range of 200-400 nm. In the ultraviolet scanning diagram of arctiin reference solution, the maximum absorption wavelength of 280 nm was determined as the determination wavelength λ 1, the detection wavelength in the ultraviolet scanning diagram of chlorogenic acid reference solution ( λ 1=280 nm) was determined, and 350 nm was the reference wavelength λ 2;the content of total lignosides in Tangjiangshenkang granules was determined with arctiin as the reference substance. [Results] The precision, accuracy, and durability of this method were fine. The concentration of arctiin was linearly correlated with the absorbance difference in the range of 0.007 95-0.071 55 mg/mL ( r =0. 999 9). The average recovery of arctiin was 100.8%, and the RSD value was 1.04% ( n =6). Calculated as arctiin, three batches of Tangjiangshenkang granules contain no less than 20% of total lignosides. [Conclusions] The method has the advantages of simple operation, good accuracy, precision and reliable stability. It can be used as the content determination and quality control method of total lignosides in Tangjiangshenkang granules.
基金the National Major Science and Technology Infrastructure Project of China“High Precision Ground-based Time Service System”(No.2017-000052-73-01-002401)the Youth Innovation Promotion Association,Chinese Academy of Sciences(No.2021407)the National Natural Science Foundation of China(No.12033007)。
文摘In this paper,we demonstrate the single-fiber and two-wavelength time transfer(SFTWTT)over a 2061 km field fiber loopback link network with a synchronous wavelength-division and time-division multiplexing access(WD-TDMA).This system utilizes wavelength-division multiplexing to avoid the impact of backscatter.In order to achieve high-precision time transfer,time-division multiplexing access is employed.This approach facilitates multiple bidirectional comparisons between local and remote devices.A digital phase-locked loop(PLL),which matches the bandwidth of the transfer system,and precision temperature control technology have been proposed to enhance the high stability of the fiber-optic time and frequency transfer system.The first on-site high-precision fiber-optic time transfer system exceeding 2000 km has been validated.Experimental results show that the stabilities of 5.6 ps@1 s and 3.1 ps@40,000 s can be achieved.The precision of time transfer over a 2061 km fiber-optic network,employing a single-fiber and two-wavelength approach,has been significantly enhanced.This study presents an average time difference of 52 ps across the distance,with a system uncertainty budgeted at 41.8 ps.This achievement signifies a substantial advancement in the realms of stability and reach for optical fiber time transfer,facilitating the development of a high-precision ground-based time service system.
