Wyniki wyszukiwania - BazTech

1

Determination of the aglycon moieties of glycosidically bound compounds in Flos Chrysanthemi by GC × GC–TOFMS

Zhou Y., Huang G., Li X., Chen F., Liu H., Yang Y., Fan Z., Jiang J., Yang J.

Acta Chromatographica

|

2018

|

Vol. 30, no. 3

195--199

EN

A credible method for determination of the aglycon moieties of glycosidically bound aroma compounds in Flos Chrysanthemi by comprehensive two-dimensional gas chromatography–time-of-flight mass spectrometry (GC × GC–TOFMS) has been proposed. The aglycon moieties of glycosidically bound aroma compounds were isolated using methyl-tert-butyl ether (MTBE) extraction following enzymatic hydrolysis. The GC × GC–TOFMS analysis was performed to comprehensively identify different forms of the released aroma components in Flos Chrysanthemi. The result shows that the limit of detection of the released aglycon moieties ranged from 0.3 to 3.1 ng/mL, the recovery of the released 1-octanol was better than 98.3%, and the intra-day and inter-day precisions of this method were 0.2 to 8.9% and 1.3 to 9.1%, respectively. The proposed method was applied to the analysis of four types of Flos Chrysanthemi (Chuju, Boju, Hangju, and Gongju). A total of 60 aglycon moieties of interest were identified in the four types of Flos Chrysanthemi. These aglycones mainly consisted of aliphatic, aromatic, monoterpene, C13-norisoprenoids, and miscellaneous compounds.

2

A rapid and sensitive UPLC–MS/MS method for determination of remimazolam and its main metabolite in human urine and its application in clinical urine recovery study

Zhou Y., Lu M., Jiang J.

Acta Chromatographica

|

2018

|

Vol. 30, no. 2

109--113

EN

Remimazolam is a new chemical entity belonging to the benzodiazepine class of sedative drugs. A sensitive and rapid method based on ultra-performance liquid chromatography–tandem mass spectrometry (UPLC–MS/MS) has been developed and validated for the determination of remimazolam and its major carboxylic acid metabolite (M1) in human urine. Urine samples were prepared by dilution and analyzed using an isocratic chromatographic separation. Inter- and intra-batch results for remimazolam were within 10.7% for accuracy and 5.5% for precision, and for M1, within 5.8% for accuracy and 4.2% for precision, respectively. This study represents the first reported example for the quantification of remimazolam and its main metabolite in human urine. Furthermore, this method has been successfully applied for the urine recovery study of remimazolam in Chinese healthy subjects. Only about 0.01% of the administered remimazolam dose was eliminated in the urine over the 24 h period in the form of unchanged remimazolam, and more than 75.1% of the administered dose was eliminated in the form of M1. Remimazolam is excreted mainly in the form of M1 in urine after intravenous administration, and there is no excessive accumulation in vivo after administration of remimazolam.

3

Diatom stratigraphy of FA-1 core, Qarun Lake, records of Holocene environmental and climatic change in Faiyum Oasis, Egypt

Zalat A. A., Marks L., Welc F., Salem A., Nitychoruk J., Chen Z., Majecka A., Szymanek M., Chodyka M., Tołoczko-Pasek A., Sun Q. L., Zhao X., Jiang J.

Studia Quaternaria

|

2017

|

Vol. 34, Nr 1

61--69

EN

This study evaluates changes in the environmental and climatic conditions in the Faiyum Oasis during the Holocene based on diatom analyses of the sediment FA-1 core from the southern seashore of the Qarun Lake. The studied FA-1 core was 26 m long and covered the time span ca. 9.000 cal. yrs BP. Diatom taxa were abundant and moderately to well-preserved throughout the core sediments. Planktonic taxa were most abundant than the benthic and epiphytic forms, which were very rare and sparsely distributed. The most dominant planktonic genera were Aulacoseira and Stephanodiscus followed by frequently distribution of Cyclostephanos and Cyclotella species. The stratigraphic distribution patterns of the recorded diatoms through the Holocene sediments explained five ecological diatom groups. Thesegroups represent distinctive environmental conditions, which were mainly related to climatic changes through the earlyand middle Holocene, in addition to anthropogenic activity during the late Holocene. Comparison of diatom assemblages in the studied sediment core suggests that considerable changes occurred in water level as well as salinity. There were several high stands of the freshwater lake level during humid, warmer-wet climatic phases marked by dominance of planktonic, oligohalobous and alkaliphilous diatoms alternated with lowering of the lake level and slight increases in salinity and alkalinity during warm arid conditions evident by prevalence of brackish water diatoms.

4

Modeling and analysis of coupled flexural-torsional spinning beams with unsymmetrical cross sections

Wang J., Li D., Jiang J.

Journal of Theoretical and Applied Mechanics

|

2017

|

Vol. 55 nr 1

213--226

EN

The structural modeling and dynamic properties of a spinning beam with an unsymmetrical cross section are studied. Due to the eccentricity and spinning, transverse deflections along the two principal directions and the torsional motion about the longitudinal axis are coupled. The structural model of the beam is established based on the Hamilton principle and by incorporating the torsional inertia. Moreover, because of its significant influence on characteristics for the non-circular cross-sectional beam, the warping effect is considered in the formulation. The proposed model is effectively validated in two cases: the spinning beam with a symmetric cross section and the cantilevered beam with an unsymmetrical cross section. Then the effects of the spinning speed on natural frequencies and mode shapes are investigated. Numerical results reveal that the critical speed is altered with respect to noncoincidence of the centroid and the shear center. For the beams with strong warping rigidities, the warping effect cannot be neglected due to significant influence on natural frequencies.

5

A hierarchical inferential method for indoor scene classification

Jiang J., Liu P., Ye Z., Zhao W., Tang X.

International Journal of Applied Mathematics and Computer Science

|

2017

|

Vol. 27, no. 4

839--852

EN

Indoor scene classification forms a basis for scene interaction for service robots. The task is challenging because the layout and decoration of a scene vary considerably. Previous studies on knowledge-based methods commonly ignore the importance of visual attributes when constructing the knowledge base. These shortcomings restrict the performance of classification. The structure of a semantic hierarchy was proposed to describe similarities of different parts of scenes in a fine-grained way. Besides the commonly used semantic features, visual attributes were also introduced to construct the knowledge base. Inspired by the processes of human cognition and the characteristics of indoor scenes, we proposed an inferential framework based on the Markov logic network. The framework is evaluated on a popular indoor scene dataset, and the experimental results demonstrate its effectiveness.

6

3-D simulation of vertical-axial tidal current turbine

Zhang Z., Ma Y., Jiang J., Liu W., Ma Q.

Polish Maritime Research

|

2016

|

nr 4

73--83

EN

Vertical-axial tidal current turbine is the key for the energy converter, which has the advantages of simple structure, adaptability to flow and uncomplex convection device. It has become the hot point for research and application recently. At present, the study on the hydrodynamic performance of vertical-axial tidal current turbine is almost on 2-D numerical simulation, without the consideration of 3-D effect. CFD (Computational Fluid Dynamics) method and blade optimal control technique are used to improve accuracy in the prediction of tidal current turbine hydrodynamic performance. Numerical simulation of vertical-axial tidal current turbine is validated. Fixed and variable deflection angle turbine are comparatively studied to analysis the influence of 3-D effect and the character of fluid field and pressure field. The method, put the plate on the end of blade, of reduce the energy loss caused by 3-D effect is proposed. The 3-D CFD numerical model of vertical-axial tidal current turbine hydrodynamic performance in this study may provide theoretical, methodical and technical reference for the optimal design of turbine.

7

Comparing the use of two kinds of droop control under microgrid islanded operation mode

Gao D., Jiang J., Qiao S.

Archives of Electrical Engineering

|

2013

|

Vol. 62, nr 2

321--331

EN

A microgrid with parallel structure operating under islanded mode is considered in this paper. Under microgrid islanded operation mode, lines bring adverse effect for power distribution between microsources (MSs). Because traditional droop control ignores this effect, MSs adopting this method can not achieve satisfactory power distribution. A kind of droop control including line compensation applied to this microgrid is proposed. It can eliminate this effect to obtain satisfactory power distribution. The relationship of two kinds of droop control with power distribution is analyzed. The reference voltage generated by droop control is applied to control output voltage of MSs. Comparison of two kinds of droop control through MATLAB/Simulink simulation is made to verify the superiority of droop control including line compensation for power distribution. The relationship between PCC voltage and output power of MSs is also presented.

8

Physical Implementation and Testing of Low-Power Adiabatic Flip-Flops with Energy-Recycling Pads

Jiang J., Hu J.

Przegląd Elektrotechniczny

|

2012

|

R. 88, nr 9b

192-195

EN

This paper presents adiabatic flip-flops based on CPAL (complementary pass-transistor adiabatic logic) circuits with energy-recycling output pad cells. The energy-recycling output pad cells for driving adiabatic chips include mainly bonding pads, ESD (electrostatic discharge) protection circuits, and two stage energy-recycling buffers. The adiabatic flip-flops and sequential circuits with energy-recycling output pad cells have been fabricated with Chartered 0.35um process. The adiabatic flip-flops have large energy savings over a wide range of frequencies.

PL

W artykule zaproponowano adiabatyczny przerzutnik bazujący na układach CPAL – complementary pass-transistor adiabatic logic). Zastosowano też blok wyjściowy z odzyskiwaniem energii.

9

Vector operation of one-cycle controlled matrix rectifier

Yang X., Jiang J., Yang X.

Archives of Electrical Engineering

|

2012

|

Vol. 61, nr 2

149-164

EN

In the paper an algorithm and computer code for the identification of the hysteresis parameters of the Jiles-Atherton model have been presented. For the identification the particle swarm optimization method (PSO) has been applied. In the optimization procedure five design variables has been assumed. The computer code has been elaborated using Delphi environment. Three types of material have been examined. The results of optimization have been compared to experimental ones. Selected results of the calculation for different material are presented and discussed. A novel vector operated one-cycle control matrix rectifier (OCC-MR) is proposed in this paper. Matrix rectifier (MR) is a generalized buck three-phase AC-DC converter with four-quadrant operation capability. MR can also be the front-stage circuit of AC-DC-AC equivalent structure of MC. One-cycle control (OCC) is a nonlinear control technique, which integrates modulation algorithm and control strategy. By applying OCC to current control loop, the OCC-MR achieves balance only in a switching cycle,and realizes unitary input power factor. Furthermore, vector operation of OCC results In minimum switching losses. In order to make up for the insufficiency of OCC on load disturbance suppression, a PID controller is added onto output voltage control to improve load regulation. The OCC-MR features great simplicity, fast dynamic response and good immunity on input disturbance. On the basis of theoretical analysis, a systematic simulation of OCC-MR is implemented by means of Matlab/Simulink. Both static state performance and dynamic state performance of OCC-MR are discussed deeply. The simulation results have proved theoretical analysis of the vector operation of OCC-MR, and the control effects are satisfactory.

10

Sequential injection analysis with spectrophotometric detection of cefadroxil and amoxicillin in pharmaceuticals

Feng S., Jiang J., Fan J., Chen X.

Chemia Analityczna

|

2007

|

Vol. 52, No. 1

83-92

EN

A fast, economical, and automated spectrophotometric method with sequential injection for determination of phenolic drugs cefadroxil and amoxicillin has been proposed. The analysis was based on the determination of the red product of the reaction of drugs with 4-amino-antipyrine in the presence of potassium hexacyanoferrate{III) in alkaline solution. Absor-bance of the investigated system was measured at 505 nm. Various chemical and physical parameters affecting the reaction have been examined. The linear ranges were 4.0-52 μg mL-1 for cefadroxi] and 2.6-87 μg mL-1 for amoxicillin, and the respective limits of detection were 0.6 μg mLμg mL-1 and 0.7 μ g mL-1. Sampling frequency was 26 h-1, and total reagent consumption was only 240 μ L per run. The proposed method has been applied for determi nation of cefadroxil and amoxicillin in pharmaceutical with RSD lower than 2.5%. The obtained results were in good agreement with these obtained by HPLC method.

PL

Zaproponowano szybką, ekonomiczną i zautomatyzowaną metodę oznaczania leków fenolowych: cefadroksilu i amoksycyliny, wykorzystującąspektrofotometrycznądetekcję we wstrzykowcj sekwencyjnej analizie. Oznaczenie polega na powstaniu czerwonego produktu reakcji leku z 4-aminoantypiryną w obecności heksacyjanożelazianu(III) w środowisku alkalicznym. Absorbancje jego mierzono przy 505 nm. Zbadano chemiczne i fizyczne parametry wpływające na przebieg reakcji. W przypadku cefadroksilu liniowy zakres wykresu kalibracyjnego odpowiada stężeniom od 4,0 do 52 μ g mL-1, w przypadku amoksycyliny - od 2,6 do 87 ug mL-1. Odpowiednio granice wykrywalności wynoszą 0.6 μgmL"' i 0,7 μgmL-1. Częstość próbkowania wy nosi 26 na godzinę, a całkowite zużycie odczynników-240 μ L-1 najednąanalizę. Metodę tę zastosowano do oznaczania cefadroksilu i amoksycyliny w preparatach farmaceutycznych z odchyleniem standardowym poniżej 2.5%. Uzyskane wyniki byry zgodnezoznaczeniami metodą HPLC.