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A New ent-Kaurane type Diterpenoid Glycoside from Inula japonica Thunb
Jiang Jiang Qin,Jia Xian Zhu,Wei Dong Zhang1,2,Yan Zhu,Jian Jun Fu,Xiao Hua Liu,Hui Zi Jin 대한약학회 2009 Archives of Pharmacal Research Vol.32 No.10
A new ent-kaurane type diterpenoid glycoside, 17-O-β-D-glucopyranosyl-16α-ent-kauran-19-oic acid (1), together with 17-hydroxy-16α-ent-kauran-19-oic acid (2), 16α,17-dihydroxyl-ent-kauran-19-oic acid (3), and 16α-hydroxy-17-acetoxy-ent- kauran-19-oic acid (4) were isolated from the aerial parts of Inula japonica Thunb. The structure of 1 was determined mainly by use of 1D and 2D NMR spectroscopic techniques including HSQC, 1H-1H COSY, HMBC, and NOESY. In addition, 4 exhibited significant inhibitory activity on NO production in LPS-stimulated RAW264.7 cells with IC50 value of 14.3 μg/mL.
Bo Zhang,Lu-Ping Zhou,Xian-Liang Zhang,Dui Li,Jia-Qi Wang,Chong-Yu Jia,Hua-Qing Zhang,Liang Kang,Ren-Jie Zhang,Cai-Liang Shen 대한척추신경외과학회 2023 Neurospine Vol.20 No.4
Objective: Hounsfield units (HU), vertebral bone quality (VBQ), and bone mineral density (BMD) can all serve as predictive indicators for thoracolumbar fragility fractures. This study aims to explore which indicator provides better risk prediction for thoracolumbar fragility fractures. Methods: Patients who have received medical attention from The First Affiliated Hospital of Anhui Medical University for thoracolumbar fragility fractures were selected. A total of 78 patients with thoracolumbar fragility fractures were included in the study. To establish a control group, 78 patients with degenerative spinal diseases were matched to the fracture group on the basis of gender, age, and body mass index. The lumbar vertebral HU, the VBQ, and the BMD were obtained for all the 156 patients through computed tomography, magnetic resonance imaging, and dual-energy x-ray absorptiometry (DEXA). The correlations among these parameters were analyzed. The area under curve (AUC) analysis was employed to assess the predictive efficacy and thresholds of lumbar vertebral HU, VBQ, and BMD in relation to the risk of thoracolumbar fragility fractures. Results: Among the cohort of 156 patients, lumbar vertebral HU exhibited a positive correlation with BMD (p < 0.01). Conversely, VBQ showed a negative correlation with HU, BMD (p < 0.05). HU and BMD displayed a favorable predictive efficacy for thoracolumbar fragility fractures (p < 0.01), with HU (AUC = 0.863) showcasing the highest predictive efficacy, followed by the DEXA-measured BMD (AUC = 0.813). VBQ (AUC = 0.602) ranked lowest among the 3 indicators. The thresholds for predicting thoracolumbar fragility fractures were as follows: HU (88),VBQ (3.37), and BMD (0.81). Conclusion: All 3 of these indicators, HU, VBQ, and BMD, can predict thoracolumbar fragility fractures. Notably, lumbar vertebral HU exhibits the highest predictive efficacy, followed by the BMD obtained through DEXA scanning, with VBQ demonstrating the lowest predictive efficacy.
Research of Acoustic Emission Testing Method with Application to Monitored for Wind Turbines
Qin Hongwu,Zhang Chao,Zhang Xian,Fan Qinyin 보안공학연구지원센터 2015 International Journal of Multimedia and Ubiquitous Vol.10 No.1
Acoustic Emission method of nondestructive check is based on exertion wave radiation and their registration during fast local material structure reorganization. It is used as a means of analysis of materials, constructions, productions control and diagnosis during operating time. In the article, it is applied to structural health monitoring of Wind Turbines. Acoustic emission testing is based condition monitoring system uses data already collected at the wind turbine controller. It is an effective way to monitor wind turbines for early warning of failures and performance issues. We used a number of measurements to develop anomaly detection algorithms and investigated classification techniques using clustering algorithms and principal components analysis for capturing fault signatures. When registering signal amplitude it is required to consider its frequency distribution connecting each amplitude rate with the corresponding vibration rate. The correlation and signal to noise ratio were evaluated by the algorithm based on frequency spectrum. Classical method of frequency distortion influence exclusion consists of FRF calculation with subsequent adjustment of received signals spectral characteristics.
Zhang, Qiang,Zhang, Xian-ku,Im, Nam-kyun The Society of Naval Architects of Korea 2017 International Journal of Naval Architecture and Oc Vol.9 No.5
Course keeping is hard to implement under the condition of the propeller stopping or reversing at slow speed for berthing due to the ship's dynamic motion becoming highly nonlinear. To solve this problem, a practical Maneuvering Modeling Group (MMG) ship mathematic model with propeller reversing transverse forces and low speed correction is first discussed to be applied for the right-handed single-screw ship. Secondly, a novel PID-based nonlinear feedback algorithm driven by bipolar sigmoid function is proposed. The PID parameters are determined by a closed-loop gain shaping algorithm directly, while the closed-loop gain shaping theory was employed for effects analysis of this algorithm. Finally, simulation experiments were carried out on an LPG ship. It is shown that the energy consumption and the smoothness performance of the nonlinear feedback control are reduced by 4.2% and 14.6% with satisfactory control effects; the proposed algorithm has the advantages of robustness, energy saving and safety in berthing practice.
Study of the flow around a cylinder from the subcritical to supercritical regimes
Zhang, Xian-Tao,Li, Zhi-Yu,Fu, Shi-Xiao,Ong, Muk Chen,Chen, Ying Techno-Press 2014 Ocean systems engineering Vol.4 No.3
The objective of the present simulations is to evaluate the applicability of the standard $k-{\varepsilon}$ turbulence model in engineering practice in the subcritical to supercritical flow regimes. Two-dimensional numerical simulations of flow around a circular cylinder at $Re=1{\times}10^5$, $5{\times}10^5$ and $1{\times}10^6$, had been performed using Unsteady Reynolds-Averaged Navier Stokes (URANS) equations with the standard $k-{\varepsilon}$ turbulence model. Solution verification had been studied by evaluating grid and time step size convergence. For each Reynolds number, several meshes with different grid and time step size resolutions were chosen to calculate the hydrodynamic quantities such as the time-averaged drag coefficient, root-mean square value of lift coefficient, Strouhal number, the coefficient of pressure on the downstream point of the cylinder, the separation angle. By comparing the values of these quantities of adjacent grid or time step size resolutions, convergence study has been performed. Solution validation is obtained by comparing the converged results with published numerical and experimental data. The deviations of the values of present simulated quantities from those corresponding experimental data become smaller as Reynolds numbers increases from $1{\times}10^5$ to $1{\times}10^6$. This may show that the standard $k-{\varepsilon}$ model with enhanced wall treatment appears to be applicable for higher Reynolds number turbulence flow.
Multiple Smooth Support Vector Machine with FCM Clustering in Hidden Space
Xian-wei Zhang,Jinjin Liang 보안공학연구지원센터 2016 International Journal of Grid and Distributed Comp Vol.9 No.9
A multiple smooth model is proposed by smoothing technique and piecewise technique for large scale data. Mapping the training data to the hidden space with a hidden function, the proposed model divides the original data into several subclasses by Fuzzy C Means (FCM), whose initial cluster centers are selected by samples with large density indexes; derives the smooth differentiable model by utilizing the entropy function to replace the plus function of the slack vector, and introduces linking rules to combine results of subclasses. Simulations demonstrate that the obtained algorithm maintains good classification accuracies, reduces the training time and hardly varies with kernel parameters.
Xian Zhang,Xiaofei Fan,Yu Xue,Yantao Wang,Wei Cai 제어·로봇·시스템학회 2017 International Journal of Control, Automation, and Vol.15 No.2
This paper is concerned with the problem of the robust exponential passive filter design for uncertainneutral-type neural networks with time-varying mixed delays. Our aim is to design a Luenberger-type filter forestimating information about the neuron states, which is required in some applied areas. By constructing an appropriateLyapunov-Krasovskii functional and using the Wirtinger-based integral inequality to estimate its derivative,a delay-range-dependent and delay-rate-dependent criterion is presented to ensure the augmented filtering dynamicsystem to be robustly exponentially stable and passive with an expected dissipation. Since the criterion is presentedin the form of linear matrix inequalities with nonlinear constraints, a cone complementarity linearization algorithmis proposed to determine the filter gain from solution to the nonlinear problem. Finally, a numerical example isgiven to demonstrate the effectiveness of the proposed method.