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A high-efficiency simulation method of wind field and its application on transmission line
Xing Fu,Xing-Heng Zhang,Hong-Nan Li,Gang Li,Hui-Juan Liu 한국풍공학회 2021 Wind and Structures, An International Journal (WAS Vol.33 No.4
Generally, the fluctuating wind is simplified as several independent one-dimensional multivariate stationary Gaussian processes in simulating a natural wind field. The correlation in the lateral, longitudinal and vertical directions should all be considered in the simulation of longitudinal wind field for the large-span spatial structures. In fact, this type of structure has lots of simulation points. The calculation amount of wind field simulation by the harmonic superposition method depends on the scale of cross-spectral density matrix, which is directly related to the number of simulated points, leading to a low efficiency when generating the time-varying wind speed. This paper innovatively proposes a high-efficiency simulation method for the longitudinal wind field based on Taylor’s hypothesis. Subsequently, the effectiveness of the proposed wind field method was verified by the numerical simulation. Finally, the dynamic responses of a transmission tower-line system under the wind loadings generated with the new method and traditional method are calculated and compared. The percentages difference of the mean and maximum axial force at the main tower members are less than 0.02% and 1%, respectively, indicating the effectiveness of the proposed time delay method. The results also show that the proposed simulation method of wind field can not only ensure the simulation accuracy, but also significantly improve the efficiency of wind speed generation, which is suitable for the wind load simulation of large-span spatial structures.
Mechanical evaluation of polymer microneedles for transdermal drug delivery: In vitro and in vivo
Rui Xuan Liu,Yu Ting He,Ling Liang,Liu Fu Hu,Yue Liu,Rui-xing Yu,Bo Zhi Chen,Yong Cui,Xin Dong Guo 한국공업화학회 2022 Journal of Industrial and Engineering Chemistry Vol.114 No.-
In this study, we reported two types of PMNs based on polylactic acid (PLA) and polyvinyl alcohol (PVA),respectively. Parafilm M film, porcine skin, and rats’ models were operated to evaluate the mechanicalproperties in vitro and in vivo to find optimal parameters for efficient insertion. Insertion depth was measuredusing Digital Force Gauge by changing insertion force and speed, respectively. Results showed thatincreasing the insertion force and speed used for PMNs application led to a significant increase in thedepth of insertion. A force of 18 N under a speed of 330 mm/min was the optimal condition for insertingPMNs array into ParafilmM film and porcine skin. In addition, PLA-MNs exhibited higher robustness andenhanced homogeneity in insertion depth compared with PVA-MNs, but PVA-MNs were able to reachmuch deeper insertion depth. Moreover, Sprague Dawley (SD) rat experiments confirmed the effectivenessof optimal insertion parameters for transdermal drug delivery. This study illustrated not only thedevelopment of novel PMNs but also the mechanical evaluation for the design of PMNs.
Application of Improved Grid Search Algorithm on SVM for Classification of Tumor Gene
Li Wenwen,Xing Xiaoxue,Liu Fu,Zhang Yu 보안공학연구지원센터 2014 International Journal of Multimedia and Ubiquitous Vol.9 No.11
According to the merits and shortcomings of the traditional gridsearch algorithm in parameters optimization of support vector machine (SVM), an improved grid search algorithm is proposed. Dichotomous search algorithm is used to reduce target searching range. First, searching range is determined roughly, and a set of parameters are obtained. Then fine search is applied in reduction the range for searching, and searching the optimum parameters.Three kinds of famous tumor gene data set are used in the comparison experiments to validate the classification accuracy of principal component analysis (PCA)-SVM and kernel principal component analysis (KPCA)-SVM. Experiment results and data analysis shows that, comparing with traditional gridsearch algorithm, the proposed method has higher classification accuracy and less search time.
Multi-modal Medical Image Fusion Based on Non-subsampled Shearlet Transform
Xing Xiaoxue,Cao Fucheng,Shang Weiwei,Liu Fu 보안공학연구지원센터 2015 International Journal of Signal Processing, Image Vol.8 No.2
In order to provide more comprehensive and effective information for cancer diagnosis and tumor treatment planning, it is necessary to fuse multi-modal medical images, such as CT/MRI image, CT/PET image, MRI/SPECT image and so on. In this paper, a multi-modal medical image fusion method based on Non-subsampled Shearlet Transform is proposed. Firstly, in this method, source images are decomposed into low-pass and high-pass subbands by NSST. Then, due to the characteristic features--large sparsity and strong contrast, the high-frequency and low-frequency coefficients of the images are fused by the different fusion rules. Finally, the image is reconstructed by the inverse non-sampled shearlet transform. In the method, the fusion rules are designed based on the regional energy and the average gradient; the image entropy, relative quality, average gradient, standard deviation and spatial frequency were used to evaluate the fusion results objectively. In the experiments, CT and MRI images are chosen to verify the method. Both the visual and the objective analysis show that the proposed method is better than the conventional Wavelet-based and non-subsampled Contourlet-based methods.
Asynchronously Input-output Finite-time Control of Positive Impulsive Switched Systems
Leipo Liu,Hao Xing,Yifan Di,Zhumu Fu,Shuzhong Song 제어·로봇·시스템학회 2020 International Journal of Control, Automation, and Vol.18 No.7
This paper considers asynchronously input-output finite-time control of positive impulsive switched systems(PISS). Firstly, the definition of input-output finite-time stability(IO-FTS) is introduced. By using the Lyapunov functional and average dwell time(ADT) approach, a state feedback controller is designed and new sufficient conditions are obtained to guarantee the corresponding closed-loop system is IO-FTS under asynchronous switching. Such conditions can be solved by linear programming. Finally, a practical example is provided to show the effectiveness of the proposed method.
Gao, Xing-Hui,Yang, Xue-Qin,Wang, Bi-Cheng,Liu, Shao-Ping,Wang, Fu-Bing Asian Pacific Journal of Cancer Prevention 2013 Asian Pacific journal of cancer prevention Vol.14 No.9
Objective: Twist, a basic helix-loop-helix transcription factor, plays a key role in the metastatic progression of human cancer. Matrix metalloproteinase (MMP)-9 is an endopeptidase that digests basement membrane type IV collagen, therefore being possibly related to tumor progression. It has been reported that Twist and matrix metalloproteinase-9 (MMP-9) are expressed in gastric cancers. However, the exact roles of Twist and MMP-9 in tumor metastasis and prognosis remain unclear. The aim of this study was to casts light on this question. Methods:Twist and MMP-9 expression in tissue sections of 37 gastric carcinomas was evaluated with immunohistochemistry. The staining results were compared with clinicopatholgic features and to patients' outcome. Results: Twist positive expression was significantly increased in gastric cancer cases with lymph node metastasis (P=0.023). But no correlations were found between MMP-9 overexpression and clinicopathologic features, such as recurrence, TNM stage, and lymph node metastasis. Overall survival (OS) was significantly correlated with recurrence, serosa invasion, TNM stages, distant metastasis, and MMP-9 (P=0.027, 0.021, 0.000, 0.024 and 0.036, respectively). Disease-free survival (DFS) was prominently related to recurrence location, serosa invasion and TNM stages (P=0.000, 0.038 and 0.003, respectively). In the Cox regression multivariate analysis, TNM stage, distant metastasis and MMP-9 were significantly associated with prognosis of gastric cancer (P=0.002, 0.019, and 0.032, respectively). Conclusions: This study showed Twist positive expression to be significantly correlated with lymph node metastasis in gastric cancer. MMP-9 overexpression is associated with OS, suggesting that MMP-9 is a prognostic indicator for survival in patients with gastric cancer.
Leipo Liu,Xiangyang Cao,Zhumu Fu,Shuzhong Song,Hao Xing 제어·로봇·시스템학회 2018 International Journal of Control, Automation, and Vol.16 No.2
This paper is concerned with the input-output finite-time control of uncertain positive impulsive switched systems(UPISS) with time-varying and distributed delays. Firstly, the definition of input-output finite-time stability is extended to UPISS, and the proof of the positivity of UPISS is also given. Then, by constructing multiple linear copositive Lyapunov functions and using the mode-dependent average dwell time(MDADT) approach, a state feedback controller is designed, and sufficient conditions are derived to guarantee that the corresponding closedloop system is input-output finite-time stable(IO-FTS). Such conditions can be easily solved by linear programming. Finally, two examples are given to demonstrate the effectiveness of the proposed method.
Behavior of circular concrete-filled steel tubular columns under pure torsion
Fa-Xing Ding,QIANG FU,Bing Wen,Qi-shi Zhou,Xue-mei Liu 국제구조공학회 2018 Steel and Composite Structures, An International J Vol.26 No.4
Concrete-filled steel tubular (CFT) columns are commonly used in engineering structures and always subjected to torsion in practice. This paper is thus devoted to investigate the mechanical behavior of circular CFT columns under pure torsion.3D finite element models based on reasonable material constitutive relation were established for analyzing the load-strain (<i>T-–γ</i>) curves of circular CFT columns under pure torsion. The numerical simulation indicated that local bulking of the steel tube in CFT columns was prevented and the shear strength and ductility of the core concrete were significantly improved due to the confinement effect between the steel tube and the core concrete. Based on the results, formulas to predict the torsional ultimate bearing capacity of circular CFT columns were proposed with satisfactory correspondence with experimental results. Besides, formulas of composite shear stiffness and the overall process of the <i>T-–γ</i> relation of circular CFT columns under pure torsion were proposed.