First‑Principles Study on Stacking Fault Energy of γ‑Fe–Mn Alloys

Chengjun Wang,Wujie Zu,Hao Wang,Yang Wang 대한금속·재료학회 2021 METALS AND MATERIALS International Vol.27 No.9

The ground state properties and generalized stacking fault energy (GSFE) of γ-Fe–Mn alloys with different Mn concentrationsare calculated by ab initio simulation. The calculation results of intrinsic stacking fault energies (ISFE) show that Mn atomshave a significant short-range effect on the ISFE; the parabolic relationship between ISFE and Mn atom concentration ofantiferromagnetic (AFM) Fe–Mn alloys is explained by the cohesive energy and density of states (DOS) of the alloys. AFMincreases ISFE of γ-Fe–Mn alloys compared to non-magnetic (NM). The importance of considering magnetic interactionsin ISFE of γ-Fe–Mn alloys is proven and it is very significant to study the deformation behavior of medium manganese steel.

Electro-optic Coefficient Measurement of the Double Electro-Optic Molecules Polymer based on Terahertz Application

Zhang Ying,Qiu Chengjun,Li You,Zhang Wenlong,Wang Xuan 보안공학연구지원센터 2014 International Journal of Control and Automation Vol.7 No.10

In the terahertz (THz) science research field, electro-optic (EO) polymer possesses many superior characters compared with mineral crystal. Two kinds of the side group EO polymer, polyphosphazene with plmaol grained by 2, 4-dinitroaniline and polyphenylacrylate containing p-nitro bisazo group, are synthesized and characterized. For higher EO coefficient, the double EO molecules polymer thin films are prepared by mixing a small nonlinear optical (NLO) molecule into the side group EO polymer. The principles of preparation are given and the EO coefficients are tested. The effect on the EO coefficients by different mixing proportion and different poling temperature are analyzed in details. Experiments results show that the double EO molecules polymer has fine stability, higher EO coefficient and can be easily processed. This kind of material has the potential to be widely applied in the emission and detection of THz radiation.

A novel prediction method of vibration and acoustic radiation for rectangular plate with particle dampers

Dongqiang Wang,Chengjun Wu 대한기계학회 2016 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.30 No.3

Particle damping technology is widely used in mechanical and structural systems or civil engineering to reduce vibration and suppress noise as a result of its high efficiency, simplicity and easy implementation, low cost, and energy-saving characteristic without the need for any auxiliary power equipment. Research on particle damping theory has focused on the vibration response of the particle damping structure, but the acoustic radiation of the particle damping structure is rarely investigated. Therefore, a feasible modeling method to predict the vibration response and acoustic radiation of the particle damping structure is desirable to satisfy the actual requirements in industrial practice. In this paper, a novel simulation method based on multiphase flow theory of gas particle by COMSOL multiphysics is developed to study the vibration and acoustic radiation characteristics of a cantilever rectangular plate with Particle dampers (PDs). The frequency response functions and scattered far-field sound pressure level of the plate without and with PDs under forced vibration are predicted, and the predictions agree well with the experimental results. Results demonstrate that the added PDs have a significant effect on vibration damping and noise reduction for the primary structure. The presented work in this paper shows that the theoretical work is valid, which can provide important theoretical guidance for low-noise optimization design of particle damping structure. This model also has an important reference value for the noise control of this kind of structure.

Optimizing location of particle damper using principles of gas-solid flow

Xiaofei Lei,Chengjun Wu,Peng Chen,Hengliang Wu,Jianyong Wang 대한기계학회 2019 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.33 No.6

Particle damping is a passive control technology with strong nonlinearity whose damping effect is relative to the vibration intensity where a particle damper is installed. Then, seeking the optimal installing location of the particle damper to improve the damping effect and vibration control performance is an important research project. To this problem, bound optimization by quadratic approximation (BOBYQA) was employed to discuss the optimal location of a particle damper at the both fixed end plate. For theoretically evaluating the damping effect and invoking it into BOBYQA, the principle of gas-solid flow was used to study the damping effect and establish the theoretical model of particle damping. Further, the estimation precision of the mathematical model was verified by experiment; the results indicate that the proposed mathematical model can more accurately predict the dynamic response of a particle damper installed at both fixed end plate. Therefore, a mathematical model was employed to discuss the optimal position of the particle damper for minimizing maximum amplitude (MMA). The results indicate that particle damper should be installed at the model top close to the monitoring point; if there are two resonances whose amplitudes are equivalent or approximate, the particle damper should be installed at the junction of these model tops.

Robust Water-Repellent Treatment of Cotton Fabrics with Polysiloxane Modified via Thiol-Ene Click Reaction

Haifeng Liu,Zhu Wang,Chengjun Sun 한국섬유공학회 2018 Fibers and polymers Vol.19 No.3

A facile and inexpensive way to prepare self-crosslinkable poly(dimethylsiloxane) (PDMS) for superhydrophobic treatment of cotton fabrics is reported in the study. Through thiol-ene click reaction between mercaptopropyltrimethoxysilane (MPTMOS) and vinyl-containing poly(dimethylsiloxane) (VPDMS), PDMS-g-TMOS can be simply and quickly synthesized. The trimethoxysilane group of PDMS-g-TMOS can react with hydroxyl group on cotton fabric and other -Si(OCH3)3 groups. The synthesized polysiloxane (PDMS-g-TMOS) was identified by FT-IR and 1H-NMR. The morphology of the treated cotton fabric was observed by SEM and XPS was used to analyze the elemental composition on the surface of cotton fabric. The analysis results indicated that the surface was fully covered with PDMS. Due to the low surface energy of PDMS and the rough surfaces of cotton fabric, the optimized water contact angle (WCA) and sliding angle were respectively 154 o±0.4 o and 14 o±0.5 o, indicating superhydrophobicity. Moreover, water spray test (AATCC Test Method 22-2010) was also applied to evaluate the water repellency of treated cotton fabric and a score of 90 was assigned according to AATCC Test Method 22- 2010. The durability of treated cotton fabric was tested by 50 laundering cycles. The resultant WCA barely decreased and the score of water spray test dropped from 90 to 80, showing the reasonable wash durability.

AITC induces MRP1 expression by protecting against CS/CSE-mediated DJ-1 protein degradation via activation of the DJ-1/Nrf2 axis

Lingling Xu,Jie Wu,Nini Li,Chengjun Jiang,Yan Guo,Peng Cao,Dianlei Wang 대한생리학회-대한약리학회 2020 The Korean Journal of Physiology & Pharmacology Vol.24 No.6

The present study aimed to examine the effect of allyl isothiocyanate (AITC) on chronic obstructive pulmonary disease and to investigate whether upregulation of multidrug resistance-associated protein 1 (MRP1) associated with the activation of the PARK7 (DJ-1)/nuclear factor erythroid 2-related factor 2 (Nrf2) axis. Lung function indexes and histopathological changes in mice were assessed by lung function detection and H&E staining. The expression levels of Nrf2, MRP1, heme oxygenase-1 (HO-1), and DJ-1 were determined by immunohistochemistry, Western blotting and reverse transcription-quantitative polymerase chain reaction. Next, the expression of DJ-1 in human bronchial epithelial (16HBE) cells was silenced by siRNA, and the effect of DJ-1 expression level on cigarette smoke extract (CSE)-stimulated protein degradation and AITC-induced protein expression was examined. The expression of DJ-1, Nrf2, HO-1, and MRP1 was significantly decreased in the wild type model group, while the expression of each protein was significantly increased after administration of AITC. Silencing the expression of DJ-1 in 16HBE cells accelerated CSE-induced protein degradation, and significantly attenuated the AITC-induced mRNA and protein expression of Nrf2 and MRP1. The present study describes a novel mechanism by which AITC induces MRP1 expression by protecting against CS/CSEmediated DJ-1 protein degradation via activation of the DJ-1/Nrf2 axis.

Event-triggered H _∞ control for T–S fuzzy nonlinear systems and its application to truck–trailer system

Cheng, Jun,Park, Ju H.,Wang, Hailing Elsevier 2016 ISA transactions Vol.65 No.-

<P><B>Abstract</B></P> <P>This paper addresses the problem of event-triggered <SUB> H ∞ </SUB> control for a class of T–S fuzzy nonlinear systems. An improved event-triggered scheme (ETS) characterized by discrete sampling is proposed, where the time-derivative of the membership function is not required. To get conservative conditions, the deviation bound of asynchronous normalized membership functions is considered. By utilizing the non-quadratic fuzzy line-integral Lyapunov functions and a free-matrix-based integral inequality, novel criteria for stabilization analysis of T–S fuzzy nonlinear systems are established. Finally, a truck–trailer system is provided to show the effectiveness of the proposed theories.</P> <P><B>Highlights</B></P> <P> <UL> <LI> An improved discrete event-triggered scheme is proposed. </LI> <LI> Some novel criteria for stabilization analysis of T–S fuzzy nonlinear systems are established. </LI> <LI> A truck–trailer system is studied to show the effectiveness and superiority of the proposed theories. </LI> </UL> </P>