Quantitative Analysis of Strength and Plasticity of a 304 Stainless Steel Based on the Stress-strain Curve

Lixin Li,Sheng Liu,Ben Ye,Shengde Hu,Zhifeng Zhou 대한금속·재료학회 2016 METALS AND MATERIALS International Vol.22 No.3

A constitutive model including the kinetics of twinning and martensitic transformation has been established based on the dislocation theory and the mixture law. The stress-strain curve of a 304 stainless steel has been measured by a tensile test. The material constants for the constitutive model are then found through an inverse analysis of the stress-strain curve measured experimentally, determining the stress-strain relationship equation and the kinetics of twinning and martensitic transformation of the investigated alloy. The volume fractions of martensitic transformation have been measured by the magnetic tester of Fischer Model MP3C. It has been shown that the calculated stress-strain curve and the volume fractions of martensitic transformation are in agreement with those obtained from experimental measurements, demonstrating that the material constants found by using the stress-strain curve can capture the underlying materials science of deformation. On this basis, the influence of twins, martensitic transformation, and mechanical behavior of austenite and martensite on the strength and plasticity of the 304 stainless steel has been discussed further.

Location Fingerprint Positioning Technology using Bat Algorithm

Song Lixin,Zhou Chuanbin,Pei Heng 보안공학연구지원센터 2016 International Journal of Security and Its Applicat Vol.10 No.9

A location fingerprint positioning technology method is proposed based on bat algorithm to improve the defect of traditional indoor location fingerprint positioning technology. These shortcomings include offline heavy workload, limited accuracy and poor robustness. The fingerprint database can generate using the middle point interpolation method and the method that channel attenuation model which instead of offline training stage. This stage realize the function of timing automatic databased updates. After that the database combines K nearest neighbor algorithm with bat algorithm in the stage of matching algorithm to realize the positioning function. Compared with the traditional method, location fingerprint positioning technology using bat algorithm reduces the overall positioning of workload and rapidly respond to the effect of the changing environment. Finally, localization performance test is carried out under the given simulation environment. The result indicates that this method improves the average precision than other algorithms about 23.14%, the vast most of the blind node position error range within 1.5 meters, which shows the advantages of positioning accuracy, robustness and adaptation to the changing environment.

Improved Particle Swarm Optimization with Dynamic Fractional Order Velocity and Wavelet Mutation

Lingyun Zhou,Lixin Ding 보안공학연구지원센터 2016 International Journal of Hybrid Information Techno Vol.9 No.5

Particle Swarm Optimization (PSO) is one of the most powerful algorithms for optimization. Traditional PSO algorithm tends to suffer from slow convergence and trapping into local optimum. In this paper, an improved PSO algorithm is proposed by combining dynamic fractional order technology and the wavelet mutation strategy. In the proposed method, a dynamic fractional order velocity update equation is designed to control the convergence rate. Furthermore, the wavelet mutation mechanism is employed to improve the swarm diversity and escape from the local optimums. The experimental results show that the proposed algorithm can provide fast convergence speed and high convergence precision based on the ten classic test functions.

EFFECT OF GRAPHITE PRECURSOR ON OXIDATION DEGREE, HYDROPHILICITY AND MICROSTRUCTURE OF GRAPHENE OXIDE

XUEBING HU,LIXIN SONG,YUN YU,JIANER ZHOU 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2014 NANO Vol.9 No.3

Graphene oxide (GO) has attracted much attention as a derivative of graphene. In addition, itappears to have many unique physicochemical properties and has been investigated widely inmany areas. Herein, we prepare GOs using °ake graphite (FG), expandable graphite (EG) andmicrocrystalline graphite (MG) as graphite precursors by the modi¯ed Hummers method. According to the X-ray di®raction (XRD), Fourier transform infrared spectroscopy, X-rayphotoelectron spectroscopy (XPS) and Raman spectroscopy, we characterize the component, thefunctional group, the chemical state of the element and the structural disorder of the obtainedGOs to reveal their oxidation degree. Besides, we evaluate the hydrophilicity of the obtained GOswith the water contact angle, and observe their microstructures by transmission electron mi-croscopy (TEM). We ¯nd that the GO prepared with EG has a higher-degree oxidation andbetter hydrophilicity, and it will be exfoliated easily and forms a monolayer or quasi-monolayerstructure. Finally, based on the structural characteristic of graphite precursor, we build theintercalation and oxidation model to illuminate the phenomenon.

PCAOB International Inspections and Merger and Acquisition Outcomes

Yongtae Kim,Lixin (Nancy) Su,Gaoguang (Stephen) Zhou,Xindong (Kevin) Zhu 한국경영학회 2018 한국경영학회 통합학술발표논문집 Vol.2018 No.8

In this study, we examine how Public Company Accounting Oversight Board (PCAOB) international inspections on non-U.S. auditors affect international Merger and Acquisition (M&A) outcomes. Using a difference-in-differences research design, we find that following the PCAOB inspections, clients of inspected auditors are more likely to become acquisition targets and if they become targets, the likelihood of deal completion increases. Acquirers also pay higher premiums to targets with PCAOB-inspected auditors, and the deal quality is higher for M&As involving targets with PCAOB-inspected auditors than those with non-inspected auditors. The effect of PCAOB inspections on M&A outcomes is more pronounced for targets with greater information risk and for those located in countries with weaker legal institutions. Collectively, our results suggest that PCAOB inspections improve the credibility of audited financial statements, reduce information risk in M&A deals, and enhance capital allocation in global markets. Our study provides novel evidence on the real economic benefits of the PCAOB international inspection program.

Development of Toxoplasma gondii Chinese I genotype Wh6 Strain in Cat Intestinal Epithelial Cells

Gui-Hua Zhao,Lixin Zhang,Lisha Dai,Haozhi Xu,Chao Xu,Ting Xiao,Jin Li,Hui Sun,Beibei Zhou,Kun Yin 대한기생충학ㆍ열대의학회 2022 The Korean Journal of Parasitology Vol.60 No.4

Felids are the unique definitive host of Toxoplasma gondii. The intestine of felid is the only site for initiating Toxoplasma gondii sexual reproduction. T. gondii excretes millions of infectious oocysts from the intestine, which are the primary source of infection. There are many difficulties in developing vaccines and drugs to control oocyst excretion due to the lack of an appropriate experimental model. Here, we established an in vitro feline intestinal epithelial cell (IEC) infection system and an efficient animal model of T. gondii Chinese 1 genotype, Wh6 strain (TgCtwh6). The Kunming mice brain tissues containing TgCtwh6 cysts were harvested 42-day post-infection. The bradyzoites were co-cultured with cat IECs in vitro at a ratio of 1:10. Five 3-month-old domestic cats were orally inoculated with 600 cysts each. The oocysts were detected by daily observation of cat feces by microscopy and polymerase chain reaction. We found that the parasite adhered and invaded cat IECs in vitro, transformed into tachyzoites, and then divided to form rose-like structures. These parasites eventually destroyed host cells, escaped, and finished the asexual reproduction process. Schizonts associated with sexual reproduction have not been observed during development in vitro cultured cells. However, schizonts were detected in all infected cat intestinal epithelial cells, and oocysts were presented in all cat feces. Our study provides a feasible cell model and an efficient infection system for the following studies of T. gondii sexual reproduction, and also lays a foundation to develop drugs and vaccines for blocking excretion and transmission of oocysts.

Design of an Input-Parallel Output-Parallel Multi-Module DC-DC Converter Using a Ring Communication Structure

Tao Hu,Muhammad Mansoor Khan,Kai Xu,Lixin Zhou,Ahmad Rana 전력전자학회 2015 JOURNAL OF POWER ELECTRONICS Vol.15 No.4

The design feasibility of a micro unidirectional DC transmission system based on an input-parallel output-parallel (IPOP) converter is analyzed in this paper. The system consists of two subsystems: an input-parallel output-series (IPOS) subsystem to step up the DC link voltage, and an input-series output-parallel (ISOP) subsystem to step down the output voltage. The two systems are connected through a transmission line. The challenge of the delay caused by the communication in the control system is addressed by introducing a ring communication structure, and its influence on the control system is analyzed to ensure the feasibility and required performance of the converter system under practical circumstances. Simulation and experiment results are presented to verify the effectiveness of the proposed design.

MiR-214 inhibits apoptosis in thyroid epithelial follicular cells induced by amiodarone through the FASL/MAPK pathway

Wen Jing,Deng Chaonan,Shi Lixin,Zhou Shi,Zhang Miao,Hu Xiaoli,Wang Nianxue,Luo Lijuan 대한독성 유전단백체 학회 2022 Molecular & cellular toxicology Vol.18 No.2

Background Hashimoto's thyroiditis (HT), also known as chronic lymphocytic thyroiditis, is one of the most common autoimmune disease (AITD) in clinical practice. It is urgent to explore the mechanism of amiodarone-induced thyroid dysfunction. Objective This study aims to assess the expression levels of miR-214 and FasL in amiodarone contact type of HT, and the effect of miR-214 on cell viability and apoptosis and potential mechanism. Results We found that miR-214 was low expressed in the tissues of amiodarone-treated thyroiditis patients. MiR-214 increased the survival rate of amiodarone-induced thyroid epithelial follicular cells and inhibited apoptosis. Mechanically, we found that miR-214 could bind to FASL and regulate MAPK signaling pathway through FASL. Conclusions Our results suggested that miR-214 could be a potential therapeutic target for Hashimoto's thyroiditis.

The Mathematic Model of "Pressing Complexion" Differential Coefficient Countermeasure Decision for Collision-avoidance

Cai Feng,Shi Aiguo,Yang Baozhang,Zhou Lixin 한국항해항만학회 2001 한국항해항만학회 학술대회논문집 Vol.3 No.-

In this article, we have done some analysis about the collision-avoidance specialty of "pressing complexion" and "pressing danger" in the meet process of two boats, and offered a mathematic model of differential coefficient countermeasure decision for collision-avoidance. which adapt to the right complexion. The basal idea is, in the right condition whatever do the coming boat do, and our boat will always adopt dynamic, continuous and the best countermeasure. When both the controlling capabilities of two boats have advantage and inferior position, we can working-out with the qualitative differential coefficient countermeasure.

Highly Efficient Photocatalysts Based on Lamellar-Shaped Bi2S3 Grown on TiO2 Monolith

Kaidi Li,Fangfang Zhang,Huiming Wang,Yalan Zhou,Lixin Zhao,Jimin Du,Yating Gao,Weimin Wang,강대준 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2018 NANO Vol.13 No.09

Here, the lamellar-shaped Bi2S3 grown on a porous TiO2 monolith was obtained by a two-step method including a sol–gel route and hydrothermal treatment. The photocatalytic activity of the as-synthesized Bi2S3/TiO2 composites was evaluated for photodegradation of methylene blue (MB) dye in aqueous solution under the visible-light irradiation. Based on our experimental results, 5% (molar ratio of Bi2S3 to TiO2) Bi2S3/TiO2 photocatalysts exhibited a maximum photodegradation rate of MB up to 96.9% under visible-light irradiation for 120 min. Our findings indicated that the lamellar-shaped Bi2S3 can extend the light absorption up to visible areas, and porous TiO2 can provide enhanced specific surface area and more mass transfer pathway to enhance the photodegradation efficiency. Furthermore, porous TiO2 can accept the electrons from the Bi2S3 conduction band due to the relatively positive electrode potential to impede the photoproduced electron and hole combination to result in advanced photocatalytic performance.