Strong convergence of strict pseudo-contractions in q-uniformly smooth Banach space

Fujun Liu,Fujun Liu,Qinghui Gao 한국전산응용수학회 2015 Journal of applied mathematics & informatics Vol.33 No.1

In this paper, we introduce a general iterativealgorithm for finding a common element of the common fixed point setof an infinite family of $\lambda_i$-strict pseudo-contractions andthe solution set of a general system of variational inclusions fortwo inverse strongly accretive operators in $q$-uniformly smoothBanach spaces. Then, we analyze the strong convergence of the iterative sequence generated by the proposed iterative algorithm under mild conditions.

Comparison of image masking methods for pump impeller blade region PIV experiments

Xiaodong Liu,Tingting Yan,Qiang Zhong,Zhuqing Liu,Fujun Wang,Yaojun Li,Wei Yang 대한기계학회 2021 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.35 No.6

Due to the blade reflection effect when applying the PIV technology to the internal flow field measurement of rotating machinery, the blade area requires special treatment. In this paper, zero-value, particle image, random number, and mean-value masking methods are compared and analyzed based on particle images from the PIV challenge and rotating impeller. The peak significance and coordinates deviations are used as the masking effect evaluation criteria. The results indicate that an increase in the interrogation window masking area proportion causes a weakening of the PIV calculation particle cluster displacement peak value. The peak position is shifted, which leads to the wrong velocity vector. The masking area proportion should not be higher than 0.7, 0.5, 0.19, and 0.22 for mean-value, random number, zero-value, and particle image masking methods, respectively. The results show that flow field calculation results near the blade boundary are more accurate for mean-value masking.

Effect of the swirl intensity on the non-reacting flowfields and fuel-air premixing characteristics for lean premixed combustors

Fujun Sun,Jianqin Suo,Zhenxia Liu 대한기계학회 2022 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.36 No.1

According to the tendency of incorporating fuel jet holes into swirler-vanes, as well as the advantages of wide operating boundary conditions and low NO x emissions of low swirl injectors for land-based gas turbines, an original lean premixed injector with convergent outlet was proposed in this paper. Based on the lean premixed injector, this paper presented laser diagnostic experiments and numerical simulations of flowfields and fuel/air premixing uniformities of S30 and S40. The results show that the axial size and the radial size of main recirculation zone (MRZ) of S30 are both smaller than those of S40, which can decrease residence time and is beneficial to NO x reduction for S30. Furthermore, the MRZ of S30 are far from the convergent outlet, which can produce detached flames and reduce the risk of flashback. The SMV at S40 and S30 convergent outlet are 0.0008 and 0.0002, respectively, both of which are lower than 0.001, which shows that both S30 and S40 obtain good fuel/air premixing uniformities. These results demonstrate that S30 (low swirl injectors) constitutes a promising technology for low emission gas turbine combustors.

Crashworthiness of Thermoplastic Woven Glass Fabric Reinforced Composite Tubes Manufactured by Pultrusion

Mingrui Liu,Biao Yan,Xiongqi Peng,Fujun Peng,Lidong Wang 한국섬유공학회 2020 Fibers and polymers Vol.21 No.2

In this paper, crashworthiness of thermoplastic woven fabric reinforced composite tubes were investigated. Thermoplastic composite tubes with various length (40 mm and 80 mm) and fiber yarn orientation with respective tolengthwise (0 o/90 o, 15 o/75 o, 30 o/60 o and 45 o/45 o) were manufactured by pultrusion and welding from home-made woven glass fabric/PP prepreg sheets. Quasi-static axial compressive tests of the composite tubes were performed under various temperatures (298 K, 358 K, 398 K and 453 K). Three crushing modes were observed: progressive folding, splaying and weld seam cracking. The influence of fiber orientation, tube length-diameter ratio and testing temperature on the peak load, mean load, specific energy absorption and crush efficiency were investigated. The results show that the peak load is controlled by fiber orientation and testing temperature. The mean force, specific energy absorption and crush efficiency are related to the three mentioned factors. Both fiber orientation and testing temperature have obviously influence on crushing modes of thermoplastic composite tubes. Length-to-diameter ratio also plays a role in crushing modes when the testing temperature is higher than the melting point of the resin.

E3 ubiquitin ligase RNF180 mediates the ALKBH5/SMARCA5 axis to promote colon inflammation and Th17/Treg imbalance in ulcerative colitis mice

Wang Kailing,Liu Fan,Muchu Budumu,Deng Jiawen,Peng Jing,Xu Yan,Li Fujun,Ouyang Miao 대한약학회 2024 Archives of Pharmacal Research Vol.47 No.7

SMARCA5, a protein in the SWI/SNF family, has been previously implicated in the development of ulcerative colitis (UC) through methylation. However, the specifi c molecular mechanisms by which SMARCA5 contributes to colonic infl ammation and the imbalance between Th17 and Treg cells remain unclear. This study was designed to explore these molecular mechanisms. A UC mouse model was established using dextran sulfate sodium induction, followed by measurements of mouse weight, disease activity index (DAI) score, colon length, pathological changes in the colon, and FITC-dextran concentration. The levels of IL-17a, IFN-γ, IL-6, TNF-α, TGF-β, and IL-10 were measured, along with the protein expression of ZO-1 and Occludin. Flow cytometry was used to assess the presence of IL-17 + CD4 + (Th17 +) cells and FOXP3 + CD25 + CD4 + (Treg +) cells in the spleen and mesenteric lymph nodes of UC mice. We observed that SMARCA5 and RNF180 were increased, while ALKBH5 was downregulated in UC mouse colon tissue. SMARCA5 or RNF180 knockdown or ALKBH5 overexpression ameliorated the colon infl ammation and Th17/Treg cell imbalance in UC mice, shown by increased body weight, colon length, FOXP3 + CD25 + CD4 + T cells, and the levels of ZO-1, Occludin, TGF-β, IL-10, and FOXP3. It decreased DAI scores, IL-17 + CD4 + T cells, and levels of IL-17a, IFN-γ, IL-6, TNF-α, and ROR-γt. ALKBH5 inhibited SMARCA5 expression via m6A modifi cation, while RNF180 reduced ALKBH5 expression via ubiquitination. Our fi ndings indicate that RNF180 aggravated the colon infl ammation and Th17/Treg cell imbalance in UC mice by regulating the ALKBH5/SMARCA5 axis.

An experimental study on low-velocity nonlinear flow in vuggy carbonate reservoirs

Haitao Wu,Fujun Li,Jiawen Liu,Jiang Chen,Xiaowei Lv,Wei Hu 한국자원공학회 2016 Geosystem engineering Vol.19 No.4

Vuggy carbonate reservoirs in the Middle East, which have characteristics such as high porosity, low permeability, and few fractures, are significantly different from fractured-vuggy carbonate reservoirs. In this study, single-phase flow experiments and core mercury injection experiments were conducted to analyze the pore size distribution and low-velocity nonlinear flow characteristics of vuggy carbonate rocks in Halfaya oilfield. The results show that the relationship between pseudo-threshold pressure gradient and permeability in matrix carbonate rocks is linear. However, vuggy type does not exhibit the same linear relationship. Compared with matrix type, vuggy carbonate rock has a nonlinear flow zone when the pressure gradient is comparatively low and the nonlinear flow characteristics are quite different from those of low-permeability sandstone reservoirs. Because of the multi-polarization of flow channel radius in vuggy carbonate rocks, fluid stepwise starts flowing as the pressure gradient increases. Vuggy carbonate rock has a pseudo-threshold pressure gradient during the low-velocity flow, but the actual threshold pressure gradient does not exist. The concept of whole channel flow pressure gradient is presented in this paper. The results contribute to improve the understanding of low-velocity flow characteristics of vuggy carbonate reservoirs.

STRONG CONVERGENCE OF STRICT PSEUDO-CONTRACTIONS IN Q-UNIFORMLY SMOOTH BANACH SPACES

Pei, Yonggang,Liu, Fujun,Gao, Qinghui The Korean Society for Computational and Applied M 2015 Journal of applied mathematics & informatics Vol.33 No.1

In this paper, we introduce a general iterative algorithm for finding a common element of the common fixed point set of an infinite family of ${\lambda}_i$-strict pseudo-contractions and the solution set of a general system of variational inclusions for two inverse strongly accretive operators in q-uniformly smooth Banach spaces. Then, we analyze the strong convergence of the iterative sequence generated by the proposed iterative algorithm under mild conditions.

OPF Calculation with Small-Signal Trajectory Constraints

Yang Yude,Mo Fujun,Liu Bin,Qin Zhijun 대한전기학회 2021 Journal of Electrical Engineering & Technology Vol.16 No.3

In order to avoid the complexity of obtaining the sensitivity in the usual optimal fl ow with small signal stability, which is easily result from the mere consideration of active power output optimization or the change of element model, a new model is proposed to improve the small-signal stability of the system by constraining the perturbation trajectory curve. Based on the time-domain simulation method, a power fl ow optimization model with small-signal trajectory constraint is established by extracting the damping ratio of the perturbation trajectory and forming constraints. The optimization calculation results of Western Systems Coordinating Council 3-generator 9-node system and China Electric Power Research Institute 6-generator 22-node system prove that the corresponding minimum damping ratio of the system increases with the increase of the constraint value of approximate damping ratio, which demonstrates the eff ectiveness of the model.

Development of a Novel 3-DOF Suspension Mechanism for Multi-Function Stylus Profiling Systems

Jia Tian,Yanling Tian,Zhiyong Guo,Fujun Wang,Dawei Zhang,Xianping Liu,Bijian Shirinzadeh 한국정밀공학회 2016 International Journal of Precision Engineering and Vol.17 No.11

This paper proposes a novel 3-DOF suspension mechanism for multi-function stylus profiling systems. Incorporating an electromagnetic force actuator, the 3-DOF suspension mechanism provides a controlled loading force. For reasons of the thermal and mechanical stability, a triangular flexure structure is utilized to support the stylus. The stiffness matrix method is used to establish the analytical stiffness model of the 3-DOF suspension mechanism. Considering the 3-DOF suspension mechanism as a 3-DOF lumped-mass-spring system, the dynamic model is established. Finite element analysis (FEA) is used to validate the established static and dynamic models of the 3-DOF suspension mechanism. A prototype is fabricated and experimental tests are carried out to characterize the mechanism’s performance. The results show that the 3-DOF suspension mechanism provides a controlled force in a range of up to 10 mN and has a working range in excess of 10 μm with a first natural frequency of 342 Hz in Z axis, indicating good capability for multi-function measurements at the micro/nano scale.