A simple area preservation correction to Stokes flows with moving interfaces

Zhilin Li 한국산업응용수학회 2008 한국산업응용수학회 학술대회 논문집 Vol.4 No.3

A simple area preserving correction scheme is proposed for incompressible Stokes flows with moving interfaces when the interface is represented by a Lagrangian formulation. The idea is to perturb the normal velocity component so that the area remains a constant. The proposed approach is coupled with the immersed interface method for Stokes equations with the surface tension. A numerical example is also presented to illustrate the efficiency of the method.

Gut Microbiota Alteration Influences Colorectal Cancer Metastasis to the Liver by Remodeling the Liver Immune Microenvironment

Yuan Na,Li Xiaoyan,Wang Meng,Zhang Zhilin,Qiao Lu,Gao Yamei,Xu Xinjian,Zhi Jie,Li Yang,Li Zhongxin,Jia Yitao 거트앤리버 소화기연관학회협의회 2022 Gut and Liver Vol.16 No.4

Background/Aims:This study aimed to explore the effect of gut microbiota-regulated Kupffer cells (KCs) on colorectal cancer (CRC) liver metastasis. Methods: A series of in vivo and in vitro researches were showed to demonstrate the gut microbiota and its possible mechanism in CRC liver metastasis. Results: Fewer liver metastases were identified in the ampicillin-streptomycin-colistin and colistin groups. Increased proportions of Parabacteroides goldsteinii, Bacteroides vulgatus, Bacteroides thetaiotaomicron, and Bacteroides uniformis were observed in the colistin group. The significant expansion of KCs was identified in the ampicillin-streptomycin-colistin and colistin groups. B. vulgatus levels were positively correlated with KC levels. More liver metastases were observed in the vancomycin group. An increased abundance of Parabacteroides distasonis and Proteus mirabilis and an obvious reduction of KCs were noted in the vancomycin group. P. mirabilis levels were negatively related to KC levels. The number of liver metastatic nodules was increased in the P. mirabilis group and decreased in the B. vulgatus group. The number of KCs decreased in the P. mirabilis group and increased in the B. vulgatus group. In vitro, as P. mirabilis or B. vulgatus doses increased, there was an opposite effect on KC proliferation in dose- and time-dependent manners. P. mirabilis induced CT26 cell migration by controlling KC proliferation, whereas B. vulgatus prevented this migration. Conclusions: An increased abundance of P. mirabilis and decreased amount of B. vulgatus play key roles in CRC liver metastasis, which might be related to KC reductions in the liver.

In Vitro Evaluation of Swine-Derived Lactobacillus reuteri: Probiotic Properties and Effects on Intestinal Porcine Epithelial Cells Challenged with Enterotoxigenic Escherichia coli K88

( Zhilin Wang ),( Li Wang ),( Zhuang Chen ),( Xianyong Ma ),( Xuefen Yang ),( Jian Zhang ),( Zongyong Jiang ) 한국미생물 · 생명공학회 2016 Journal of microbiology and biotechnology Vol.26 No.6

Probiotics are considered as the best effective alternatives to antibiotics. The aim of this study was to characterize the probiotic potential of lactobacilli for use in swine farming by using in vitro evaluation methods. A total of 106 lactic acid bacterial isolates, originating from porcine feces, were first screened for the capacity to survive stresses considered important for putative probiotic strains. Sixteen isolates showed notable acid and bile resistance, antibacterial activity, and adherence to intestinal porcine epithelial cells (IPEC-1). One isolate, LR1, identified as Lactobacillus reuteri, was selected for extensive study of its probiotic and functional properties in IPEC-1 cell models. L. reuteri LR1 exhibited good adhesion to IPEC-1 cells and could inhibit the adhesion of enterotoxigenic Escherichia coli (ETEC) to IPEC-1 cells. L. reuteri LR1 could also modulate transcript and protein expression of cytokines involved in inflammation in IPEC-1 cells; the Lactobacillus strain inhibited the ETEC-induced expression of proinflammatory transcripts (IL-6 and TNF-α) and protein (IL-6), and increased the level of anti-inflammatory cytokine (IL-10). Measurement of the permeation of FD-4 showed that L. reuteri LR1 could maintain barrier integrity in monolayer IPEC-1 cells exposed to ETEC. Immunolocalization experiments showed L. reuteri LR1 could also prevent ETEC-induced tight junction ZO-1 disruption. Together, these results indicate that L. reuteri LR1 exhibits desirable probiotic properties and could be a potential probiotic for use in swine production.

Analysis and Optimization of Energy Consumption for Multi-part Printing Using Selective Laser Melting and Considering the Support Structure

Zhilin Ma,Mengdi Gao,Kai Guo,Qingyang Wang,Lei Li,Conghu Liu,Guang Zhu,Zhifeng Liu 한국정밀공학회 2023 International Journal of Precision Engineering and Vol.10 No.3

Selective laser melting (SLM) can form complex and precise metal parts simultaneously and is widely used in medical and aerospace fields. The support structure plays an important role in SLM process, including supporting the overhanging structure, dissipating heat, and minimizing geometric deformation caused by internal stress. However, a non-optimal support structure causes increased energy and material consumption during processing and must be removed afterward to allow for utilization of the parts. Existing support structure design methods only consider reducing the support of a single part, and research on the support and energy consumption of simultaneous multi-part printing is lacking. Therefore, to reduce the energy and material consumption of simultaneous multi-part printing by SLM and improve processing efficiency, an energy consumption analysis and optimization method is proposed in this study from the perspective of the support structure. Based on previous studies on energy consumption distribution of the additive manufacturing process, a multi-component SLM energy consumption and material consumption model was established. Furthermore, a shared-support optimization strategy for simultaneous multi-part processing is proposed. For optimization, the method selects the appropriate printing direction of one part, and then combines multiple parts to form a shared support structure to minimize energy consumption. Finally, under the constraint of minimizing the mass, an optimization strategy of the SLM multi-part shared support combination is established, and the purpose of reducing the energy consumption and material consumption of the SLM is achieved under the premise of ensuring the geometric accuracy of the parts. The method was applied to the manufacturing process of a group of parts with a beam structure. Compared with the printing method using independent support, the shared support structure method reduced energy consumption more than 5.5%, material consumption for the support structure more than 17.2%, and printing time to a certain extent. This method effectively improves SLM production efficiency and sustainability and provides strategic support for additive manufacturing designers and producers.

A SEPIC Flyback DC-DC Converter with GaN Switching Device

Li Lanyu,Jiang Zhilin,Jiang Yanfeng 대한전기학회 2023 Journal of Electrical Engineering & Technology Vol.18 No.4

A high-efficiency interleaved DC–DC converter based on SEPIC topology is developed in the paper, which can be used for micro photovoltaic inverter. Two flyback transformers in parallel connection can be controlled with single gallium nitride (GaN) switching power device. This is especially useful for the cost-down solution for high power situation with multiple flyback transformers in parallel connection. Using the single GaN switching device for double flyback transformers can suppress the output voltage ripple, while reduce the cost. In the paper, the detailed theoretical derivation on the novel topology is conducted. The simulation on the converter is carried out to verify the theoretical analysis. Finally, the topology is implemented on PCB board, experimentally showing the feasibility of the proposed converter.

Influencing factor analysis of water invasion in condensate gas reservoir with bottom water based on fuzzy comprehensive evaluation and orthogonal experiment

Wende Yan,Zhilin Qi,Yingzhong Yuan,Xiaoliang Huang,Jiqiang Li 한국자원공학회 2019 Geosystem engineering Vol.22 No.6

Condensate oil and water invasion coexist in the condensate gas reservoir with bottom water. Because of influences of condensate oil pollution and water invasion, gas recovery obviously decreases. There are many factors influencing water invasion in a condensate gas reservoir with bottom water, including static petrophysical properties and dynamic operational conditions. Various factors play different roles in the process of water invasion, and the comprehensive effects of them on water invasion are difficult to be determined because these factors interfere with each other. With gas reservoir engineering method and numerical simulation technology, the factors including acuifer size, height of water avoidance, permeability, effective gas pay thickness, condensate oil saturation and gas well production rate on water invasion are researched. Water breakthrough time, stable production period and gas recovery are calculated for different cases under different parameter combinations through fuzzy comprehensive evaluation and orthogonal experiment design. Then sensitivities of these factors are analyzed and main factors influencing water invasion are selected and sequenced. The research supply theoretical basis for preventing and controlling water invasion thus improves development effect of condensate gas reservoir with bottom water.

Sliding Mode Control for Nonlinear Discrete Networked Cascade Control Systems With Uncertain Delay

Zhaoping Du,Zhilin Zou,Hui Ye,Jianzhen Li 제어·로봇·시스템학회 2023 International Journal of Control, Automation, and Vol.21 No.12

In this paper, the problems of modeling and sliding mode control for a class of nonlinear discrete networked cascade control systems (NCCSs) are studied. Firstly, a class of discrete networked cascade control systems with nonlinear disturbance is considered, the sliding mode control is introduced and the model of the system is established. Based on this model and the Lyapunov functional method, the state feedback primary controller and the sliding mode secondary controller for this system are co-designed. Finally, an example of a thermal power plant is given to illustrate the effectiveness of the proposed co-design method. The main advantages are that the sliding mode control is introduced into cascade control system (CCS) and the design method of sliding mode controller for this system is proposed for the first time. On the premise of ensuring the stability of the system, it can be driven to the sliding mode surface in a limited time, and remain on the sliding mode surface in all subsequent times. The method can achieve better results and be applied to the corresponding industrial system with networked cascade control structure.

Integration of Additive Manufacturing in Casting: Advances, Challenges, and Prospects

Mengdi Gao,Lei Li,Qingyang Wang,Zhilin Ma,Xinyu Li,Zhifeng Liu 한국정밀공학회 2022 International Journal of Precision Engineering and Vol.9 No.1

Additive manufacturing (AM) is a novel manufacturing technology that can create highly customized products with more complex geometries than traditional techniques. Despite its significant advantages, including the freedom of design, mass customization, and ability to produce complex structures, AM consumes a large amount of energy and incurs high costs. In addition, AM suffers from long production cycles and low production efficiency in the large-scale manufacturing of metal structures. This study offers a review of the existing literature focused on metal AM technology. To avoid the shortcomings of AM and highlight its bene fits, which are widely used for manufacturing in combination with casting. The current combination application of AM and casting is reviewed to provide solutions to the problem of manufacturing large metal components from the perspective of the use of different AM technology and quality control in casting. However, such integration is insufficient for producing large castings with complex shapes, structures, or multiple features. Therefore, a novel method for integrating AM into casting to enable the manufacture of large scale metal parts with complex shapes is introduced as a topic for possible future research. This method divides complex castings with multiple features into an AM processing part and the casting substrate. The complex features were processed by AM on the fabricated casting substrate. This study provides a review of the application of AM into casting and presents a novel idea for the integration application of AM and other processes. This promising method has significant value for future study.

Optimization analysis of factors affecting hydrocarbon gas drive based on orthogonal experimental design

Wei Huang,Shenglai Yang,Zhilin Wang,Xiaowei Lv,Hao Lei,Li Chen 한국자원공학회 2014 Geosystem engineering Vol.17 No.6

To improve the ultimate recovery of reservoirs and to increase the economic benefit of oilfields, we feel obliged to study on various factors affecting the development effect of hydrocarbon gas injection and its influence in terms of ultimate recovery. Thus, we can formulate a reasonable and feasible scheme on effective implementation of hydrocarbon gas drive. Take Q28 fault-block as an example; five main factors affecting the development effect of hydrocarbon gas injection have been screened out, four different levels of each influence factor has been set up; the orthogonal experiment method has been adopted to design 16 different combination schemes of 5 factors. Numerical reservoir simulation predicted the final recovery under the different combination schemes. Following are the range analysis and variance analysis of entire results so that the major and minor factors affecting the final recovery and the best range of each factor can be confirmed. The order sequence from major to minor factors: gas injection slug size, gas injection time, gas–water ratio, pressure level, and injection rate. This method is significant on its guidance for hydrocarbon gas injection in this area.

Preparation, Characterization and Luminescence Properties of a Novel 1,10-Phenanthroline-Functionalized Polyimide and Its Europium(III) Complexes

Zhiyong Chen,Jianjun Lu,Xuping Li,Xuting Jin,Lijuan Shi,Miaoqing Liu,Zhilin Sun 한국고분자학회 2015 Macromolecular Research Vol.23 No.9

A novel 1,10-phenanthroline-functionalized polyimide (CMPI-Phen) was prepared as polymer matrix by the nucleophilic substitution reaction between chloromethylated polyimide (CMPI) and 5-amino-1,10-phenanthroline (NH2-Phen). Then, two kinds of luminescent materials of 1,10-phenanthroline-functionalized polyimide containing Eu(III) complexes, were obtained by two different methods. Their structures and properties were characterized by Fourier transform infrared (FTIR) spectroscopy, 1H nuclear magnetic resonance (NMR) spectroscopy, elemental analysis, inductively coupled plasma (ICP), gel permeation chromatography (GPC), thermogravimetric analysis (TGA), X-ray diffraction (XRD), luminescence spectrometry, and luminescence decay analysis. Investigations revealed that both the CMPI-Phen-Eu(III) and CMPI-Phen-Eu(TTA)3 display highly efficient red emissions, suggesting their potential application as luminescent materials. However, compared with CMPI-Phen-Eu(III), CMPI-Phen-Eu(TTA)3, where TTA stands for thenoyltrifluoroacetone, exhibits more excellent and stable fluorescence intensity and longer luminescence lifetime (134.30 μs). The weight-average molecular weights of CMPI-Phen-Eu(III) and CMPI-Phen- Eu(TTA)3 are 2.40×104 and 3.11×104, respectively. The Eu contents of CMPI-Phen-Eu(TTA)3 and CMPI-Phen-Eu(III) were measured by ICP to be 7.00% and 5.92%, respectively. TGA demonstrated that both CMPI-Phen-Eu(III) and CMPI-Phen-Eu(TTA)3 have high thermal stability and their 5% loss weight temperatures were 356 and 280 oC, respectively. Moreover, both CMPI-Phen-Eu(III) and CMPI-Phen-Eu(TTA)3 were soluble in polar solvents such as dimethylformamide (DMF), dimethylacetamide (DMAc), 1-methyl-2-pyrrolidone (NMP), and dimethylsulfoxide (DMSO) under heating conditions, and could be easily cast into tough thin films.