• Title/Summary/Keyword: Wuhan University

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Flat-bottomed design philosophy of Y-typed bifurcations in hydropower stations

  • Wang, Yang;Shi, Chang-zheng;Wu, He-gao;Zhang, Qi-ling;Su, Kai
    • Structural Engineering and Mechanics
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    • v.57 no.6
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    • pp.1085-1105
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    • 2016
  • The drainage problem in bifurcations causes pecuniary losses when hydropower stations are undergoing periodic overhaul. A new design philosophy for Y-typed bifurcations that are flat-bottomed is proposed. The bottoms of all pipe sections are located at the same level, making drainage due to gravity possible and shortening the draining time. All fundamental curves were determined, and contrastive analysis with a crescent-rib reinforced bifurcation in an actual project was conducted. Feasibility demonstrations were researched including structural characteristics based on finite element modeling and hydraulic characteristics based on computational fluid dynamics. The new bifurcation provided a well-balanced shape and reasonable stress state. It did not worsen the flow characteristics, and the head loss was considered acceptable. The proposed Y-typed bifurcation was shown to be suitable for pumped storage power stations.

HOXB7 Predicts Poor Clinical Outcome in Patients with Advanced Esophageal Squamous Cell Cancer

  • Long, Qing-Yun;Zhou, Jun;Zhang, Xiao-Long;Cao, Jiang-Hui
    • Asian Pacific Journal of Cancer Prevention
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    • v.15 no.4
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    • pp.1563-1566
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    • 2014
  • Background: Esophageal squamous cell carcinoma (ESCC) accounts for most esophageal cancer in Asia, and is the sixth common cause of cancer-related deaths worldwide. Previous studies indicated HOXB7 is overexpressed in ESCC tissues, but data on prognostic value are limited. Methods: A total of 76 advanced ESCC cases were investigated. Immunohistochemistry (IHC) was used to detect the expression levels of HOXB7 and Kaplan-Meier curves and Cox regression models to determine prognostic significance. Stratified analysis was also performed according to lymph node (LN) status. Results: Kaplan-Meier curve analysis indicated that HOXB7 positive patients had significantly shorter overall survival (OS) than HOXB7 negative patients. Multivariate analysis using the Cox proportional hazards model indicated only TNM stage and HOXB7 expression to be independent predictors of overall survival of advanced ESCC patients. HOXB7 indicated poor OS in both lymph node negative (LN-) and lymph node positive (LN+) patients. Conclusion: HOXB7 predicts poor prognosis of advanced ESCC patients and can be applied as an independent prognostic predictor.

Autophagy-associated Targeting Pathways of Natural Products during Cancer Treatment

  • Zhang, Shu-Fang;Wang, Xiao-Lu;Yang, Xiao-Qi;Chen, Ning
    • Asian Pacific Journal of Cancer Prevention
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    • v.15 no.24
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    • pp.10557-10563
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    • 2015
  • It is well known that conventional chemotherapy and radiation therapy can result in toxicity to both normal cells and tumor cells, which causes limitations in the application of these therapeutic strategies for cancer control. Novel and effective therapeutic strategies for cancers with no or low toxicity for normal cells are a high priority. Therefore, natural products with anticancer activity have gained more and more attention due to their favorable safety and efficacy profiles. Pre-clinical and clinical studies have demonstrated that several representative natural compounds such as resveratrol, epigallocatechin-3-gallate, curcumin, allicin and ginsenosides have obvious anticancer potential. In this article, we summarize autophagy-associated targeting pathways of such natural products for inducing the death of cancer cells, and discuss the core autophagic pathways involved in cancer treatments. Recent advances in the discovery, evaluation and exploitation of natural compounds as therapeutic agents for cancers will provide references and support in pre-clinical and clinical application of novel natural drugs for the treatment of primary and metastatic tumors in the future.

Hierarchical Regression for Single Image Super Resolution via Clustering and Sparse Representation

  • Qiu, Kang;Yi, Benshun;Li, Weizhong;Huang, Taiqi
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.11 no.5
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    • pp.2539-2554
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    • 2017
  • Regression-based image super resolution (SR) methods have shown great advantage in time consumption while maintaining similar or improved quality performance compared to other learning-based methods. In this paper, we propose a novel single image SR method based on hierarchical regression to further improve the quality performance. As an improvement to other regression-based methods, we introduce a hierarchical scheme into the process of learning multiple regressors. First, training samples are grouped into different clusters according to their geometry similarity, which generates the structure layer. Then in each cluster, a compact dictionary can be learned by Sparse Coding (SC) method and the training samples can be further grouped by dictionary atoms to form the detail layer. Last, a series of projection matrixes, which anchored to dictionary atoms, can be learned by linear regression. Experiment results show that hierarchical scheme can lead to regression that is more precise. Our method achieves superior high quality results compared with several state-of-the-art methods.

Two scale modeling of behaviors of granular structure: size effects and displacement fluctuations of discrete particle assembly

  • Chu, Xihua;Yu, Cun;Xiu, Chenxi;Xu, Yuanjie
    • Structural Engineering and Mechanics
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    • v.55 no.2
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    • pp.315-334
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    • 2015
  • This study's primary aim is to check the existence of a representative volume element for granular materials and determine the link between the properties (responses) of macro structures and the size of the discrete particle assembly used to represent a constitutive relation in a two-scale model. In our two-scale method the boundary value problem on the macro level was solved using finite element method, based on the Cosserat continuum; the macro stresses and modulus were obtained using a solution of discrete particle assemblies at certain element integration points. Meanwhile, discrete particle assemblies were solved using discrete element method under boundary conditions provided by the macro deformation. Our investigations focused largely on the size effects of the discrete particle assembly and the radius of the particle on macro properties, such as deformation stiffness, bearing capacity and the residual strength of the granular structure. According to the numerical results, we suggest fitting formulas linking the values of different macro properties (responses) and size of discrete particle assemblies. In addition, this study also concerns the configuration and displacement fluctuation of discrete particle assemblies on the micro level, accompanied with the evolution of bearing capacity and deformation on the macro level.

Slender RC columns strengthened with combined CFRP and steel jacket under axial load

  • Lu, Yi-yan;Li, Na;Li, Shan;Ou, Tian-yan
    • Steel and Composite Structures
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    • v.19 no.5
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    • pp.1077-1094
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    • 2015
  • This paper presents an experimental study on the effectiveness of simultaneous application of carbon fiber-reinforced polymer (CFRP) and steel jacket in strengthening slender reinforced concrete (RC) column. The columns were 200 mm square cross section with lengths ranging from 1600 to 3000 mm. Ten columns were tested under axial load. The effects of the strengthening technique, slenderness ratio, cross-section area of steel angle and CFRP layer number were examined in terms of axial load-axial strain curve, CFRP strain, steel strip strain and steel angle strain. The experiments indicate that strengthening RC columns with combined CFRP and steel jacket is effective in enhancing the load capacity, ductility and energy dissipation capacity of RC column. Based on the existing models for RC columns strengthened with CFRP and with steel jacket, a design formula considering a slenderness reduction factor is proposed to predict the load capacity of the RC columns strengthened with combined CFRP and steel jacket. The predictions agree well with the experimental results.

Analysis of vortex induced vibration frequency of super tall building based on wind tunnel tests of MDOF aero-elastic model

  • Wang, Lei;Liang, Shuguo;Song, Jie;Wang, Shuliang
    • Wind and Structures
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    • v.21 no.5
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    • pp.523-536
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    • 2015
  • To study the vibration frequency of super high-rise buildings in the process of vortex induced vibration (VIV), wind tunnel tests of multi-degree-of-freedom (MDOF) aero-elastic models were carried out to measure the vibration frequency of the system directly. The effects of structural damping, wind field category, mass density, reduced wind velocity ($V_r$), as well as VIV displacement on the VIV frequency were investigated systematically. It was found that the frequency drift phenomenon cannot be ignored when the building is very high and flexible. When $V_r$ is less than 8, the drift magnitude of the frequency is typically positive. When $V_r$ is close to the critical wind velocity of resonance, the frequency drift magnitude becomes negative and reaches a minimum at the critical wind velocity. When $V_r$ is larger than12, the frequency drift magnitude almost maintains a stable value that is slightly smaller than the fundamental frequency of the aero-elastic model. Furthermore, the vibration frequency does not lock in the vortex shedding frequency completely, and it can even be significantly modified by the vortex shedding frequency when the reduced wind velocity is close to 10.5.

Axial behavior of RC columns strengthened with SCC filled square steel tubes

  • Lu, Yi-Yan;Liang, Hong-Jun;Li, Shan;Li, Na
    • Steel and Composite Structures
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    • v.18 no.3
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    • pp.623-639
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    • 2015
  • Self-compacting Concrete (SCC) Filled Square steel Tubes (SCFST) was used to strengthen square RC columns. To establish the efficiency of this strengthening method, 17 columns were tested under axial compression loading including 3 RC columns without any strengthening (WRC), 1 RC column strengthened with concrete jacket (CRC), 13 RC columns strengthened with self-compacting concrete filled square steel tubes (SRC). The experimental results showed that the use of SCFST is interesting since the ductility and the bearing capacity of the RC columns are greatly improved. The improvement ratio is significantly affected by the nominal wall thickness of steel tubes (t), the strength grade of strengthening concrete (C), and the length-to-width ratio (L / B) of the specimens. In order to quantitatively analyze the effect of these test parameters on axial loading behavior of the SRC columns, three performance indices, enhancement ratio (ER), ductility index (DI), and confinement ratio (CR), were used. The strength of the SRC columns obtained from the experiments was then employed to verify the proposed mode referring to the relevant codes. It was found that codes DBJ13-51 could relatively predict the strength of the SRC columns accurately, and codes AIJ and BS5400 were relatively conservative.

Study on the frequency of self-excited pulse jet

  • Wang, Jian;Li, Jiangyun;Guan, Kai;Ma, Tianyou
    • International Journal of Fluid Machinery and Systems
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    • v.6 no.4
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    • pp.206-212
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    • 2013
  • Self-excited pulse jet is a specific nozzle with a closed chamber which can change a continuous jet into a pulse one. Energy of the pulse jet can be output not only unevenly but also with multifrequency. With the peak pressure of pulse jet, the hitting power would be 2~2.5 times higher than that of continuous jet. In order to reveal the correlation between the self-excited pulse frequency and nozzle diameter ratio, nozzle spacing and operating pressure, the model of 3D unsteady cavitation model has been used. We found that with the same nozzle structure parameters and the different operating pressure, the self-excited frequency and the width of peak crest are different, but the wave profiles are similar. With FFT, we also found that the less bandwidth of amplitude in low frequency range will lead to the wider wave crest of outlet velocity in its time domain, and the larger force of the strike will be gained. By studying the St of self-excite nozzle, not only the frequency of a certain nozzle can be predicted, but also a nozzle structure with a certain frequency can be designed.

A New Route Optimization Scheme for Network Mobility: Combining ORC Protocol with RRH and Using Quota Mechanism

  • Kong, Ruoshan;Feng, Jing;Gao, Ren;Zhou, Huaibei
    • Journal of Communications and Networks
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    • v.14 no.1
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    • pp.91-103
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    • 2012
  • Network mobility (NEMO) based on mobile IP version 6 has been proposed for networks that move as a whole. Route optimization is one of the most important topics in the field of NEMO. The current NEMO basic support protocol defines only the basic working mode for NEMO, and the route optimization problem is not mentioned. Some optimization schemes have been proposed in recent years, but they have limitations. A new NEMO route optimization scheme-involving a combination of the optimized route cache protocol (ORC) and reverse routing header (RRH) and the use of a quota mechanism for optimized sessions (OwR)-is proposed. This scheme focuses on balanced performance in different aspects. It combines the ORC and RRH schemes, and some improvements are made in the session selection mechanism to avoid blindness during route optimization. Simulation results for OwR show great similarity with those for ORC and RRH. Generally speaking, the OwR's performance is at least as good as that of the RRH, and besides, the OwR scheme is capable of setting up optimal routing for a certain number of sessions, so the performance can be improved and the cost of optimal routing in nested NEMO can be decreased.