Improvement on Mechanical Properties of a bcc Matrix Al8(FeCuCrMn)92 High-Entropy Alloy by Phase Modulation of Interstitial Carbon Element

Conghui Hu,Jianlei Zhang,Yunhu Zhang,Ke Han,Changjiang Song,Qijie Zhai 대한금속·재료학회 2022 METALS AND MATERIALS International Vol.28 No.2

High-entropy alloys (HEAs) are novel multi-element alloys based on five or more constituent elements in a range of 5–35 at%. Here we present a method to improve strength of a body-centered cubic (bcc) matrix HEA without loss of ductility. Theimprovement was achieved by phase modulation combined other strengthening effect of interstitial carbon addition. Carbonaddition can enhance strength and retain good ductility in some steels because carbon increases the volume fraction offace-centered cubic (fcc) phase. We used the same principle to design and fabricate a set of Al8(FeCuCrMn)92Cx (x = 0, 1,2, 3, 4 at%) HEAs under near-rapid solidification. Our results showed that carbon addition modulated constituent phases byincreasing the volume fraction of fcc phase and carbides. As a result, addition of carbon increased yield strength of this bccmatrix HEA. But the ductility decreased, especially when carbon content was higher than 3 at%, which was ascribed to unevendistribution of Cu-rich fcc phase and carbides precipitated in bcc phase region. After annealing at 1173 K for 2 h, additionof 1 at% carbon improved yield strength without compressive fracture. It demonstrated that a proper carbon content additionwith annealing can enhance the yield strength without loss of ductility for this bcc matrix HEA. Thus, interstitial carbon additionis a meaningful method to improve the mechanical properties by phase modulation combined other strengthening effect.

Research on LADRC strategy of PMSM for road-sensing simulation based on differential evolution algorithm

Zhang, Hui,Wang, Yuyuan,Zhang, Guowang,Tang, Conghui The Korean Institute of Power Electronics 2020 JOURNAL OF POWER ELECTRONICS Vol.20 No.4

A linear active disturbance rejection control (LADRC) strategy for permanent magnet synchronous motor (PMSM) for road-sensing based on the differential evolution (DE) algorithm is proposed in this paper, called DE-LADRC, to obtain the better dynamic and steady-state responses of the road-sensing simulation in electric vehicle (EV) steering-by-wire (SBW) systems. Since the novel control method ignores the time delay modules in digital motor control, the controlled object is regarded as a first-order inertial link to design a first-order LADRC controller. Then aiming to solve the problem where the values of the controller parameters are changed and difficult to tune due to ignoring the time delay modules in the first-order LADRC controller, the differential evolution (DE) algorithm is designed to find the optimal controller parameters by self-tuning. Experiment results indicate the effectiveness and convergence of the DE-LADRC, as well as the correctness of the road-sensing planning. In addition, the DE-LADRC can provide the smoother feel and real-time road-sensing for driver due to experiment of a Hardware in the Loop (HIL) platform under convergent iteration.

Modeling and simulation of drying characteristics on flexible filamentous particles in rotary dryers

Conghui Gu,Chao Zhang,Xin Zhang,Naihong Ding,Bin Li,Zhulin Yuan 한국화학공학회 2017 Korean Journal of Chemical Engineering Vol.34 No.1

Experiments were conducted to demonstrate the effects of the drum wall temperature on the heat and mass transfer in rotary dryers. The drying characteristics of flexible filamentous particles in rotary dryers were further explored. In addition, the inlet and outlet temperatures and moisture contents of granular particles were measured. As a result, the good agreement between the simulations and experiments verified the rationale and feasibility of the numerical method. Therefore, the approach was adopted to evaluate the temperature and moisture content of wet granular particles in a rotary dryer in different conditions, for instance, drum wall temperature and rotational speed. The results revealed that the higher drum wall temperature led to hotter particles with lower outlet moisture content. Conversely, the higher rotational speed resulted in cooler particles with higher outlet moisture content due to the decrease of residence time in the rotary dryer.

<i>OsASR5</i> enhances drought tolerance through a stomatal closure pathway associated with ABA and H ₂ O ₂ signalling in rice

Li, Jinjie,Li, Yang,Yin, Zhigang,Jiang, Jihong,Zhang, Minghui,Guo, Xiao,Ye, Zhujia,Zhao, Yan,Xiong, Haiyan,Zhang, Zhanying,Shao, Yujie,Jiang, Conghui,Zhang, Hongliang,An, Gynheung,Paek, Nam‐,Cho John Wiley and Sons Inc. 2017 Plant biotechnology journal Vol.15 No.2

<P><B>Summary</B></P><P>Drought is one of the major abiotic stresses that directly implicate plant growth and crop productivity. Although many genes in response to drought stress have been identified, genetic improvement to drought resistance especially in food crops is showing relatively slow progress worldwide. Here, we reported the isolation of <I>abscisic acid</I>,<I> stress</I> and <I>ripening</I> (<I>ASR</I>) genes from upland rice variety, IRAT109 (<I>Oryza sativa</I> L. ssp. <I>japonica</I>), and demonstrated that overexpression of <I>OsASR5</I> enhanced osmotic tolerance in <I>Escherichia coli</I> and drought tolerance in <I>Arabidopsis</I> and rice by regulating leaf water status under drought stress conditions. Moreover, overexpression of <I>OsASR5</I> in rice increased endogenous ABA level and showed hypersensitive to exogenous ABA treatment at both germination and postgermination stages. The production of H<SUB>2</SUB>O<SUB>2</SUB>, a second messenger for the induction of stomatal closure in response to ABA, was activated in overexpression plants under drought stress conditions, consequently, increased stomatal closure and decreased stomatal conductance. In contrast, the loss‐of‐function mutant, <I>osasr5</I>, showed sensitivity to drought stress with lower relative water content under drought stress conditions. Further studies demonstrated that OsASR5 functioned as chaperone‐like protein and interacted with stress‐related HSP40 and 2OG‐Fe (II) oxygenase domain containing proteins in yeast and plants. Taken together, we suggest that <I>OsASR5</I> plays multiple roles in response to drought stress by regulating ABA biosynthesis, promoting stomatal closure, as well as acting as chaperone‐like protein that possibly prevents drought stress‐related proteins from inactivation.</P>

The Effect of Cr on Phase Transformation Behavior of Austenite in Fe-20Mn-9Al-1.2C-xCr Low-density Steels During Isothermal Aging

Jianlei Zhang,Yueshan Jiang,Conghui Hu,Gang Ji,Changjiang Song,Qijie Zhai 대한금속·재료학회 2022 METALS AND MATERIALS International Vol.28 No.11

The influence of Cr on the microstructural evolution of austenite in Fe-20Mn-9Al-1.2C-xCr (wt%, x = 0, 3 and 6) low-densitysteels during isothermal aging at 650 °C for various durations was systematically investigated. With the isothermal agingprocessed, the 0Cr and 3Cr samples underwent the divorced eutectoid transformation followed by the eutectoid transformation,while only the eutectoid transformation was observed in the 6Cr sample. Meanwhile, increasing Cr content changedthe eutectoid transformation products from ferrite + κ-carbide in the 0Cr sample to ferrite + κ-carbide + M23C6carbide in the3Cr sample, and to ferrite + M7C3carbide in the 6Cr sample. The Cr addition significantly increased the A1 temperature (655°C) of the 0Cr sample to 712 °C of the 3Cr sample, and to 841 °C of the 6Cr sample. As a result, the temperature differencebetween the A1 temperature and experimental phase transformation temperature (650 °C) was enlarged, which provided agreater driving force for the eutectoid transformation and accelerated the transformation rate of eutectoid transformation. Inaddition, the Cr addition had a significant effect on the diffusion of constituent elements, decreased the interlayer spacingof pearlite structure from 625 ± 30 nm in the 0Cr sample to 385 ± 25 nm in the 3Cr sample, and to 150 ± 20 nm in the 6Crsample, refining the eutectoid structure. These findings revealed the mechanism regarding the effect of Cr addition on theeutectoid transformation of austenite, offering valuable insights into the microstructure design of high-performance lowdensitysteels.

Downstream Neighbor of Son Overexpression is Associated With Breast Cancer Progression and a Poor Prognosis

Yufeng Qi,Haodong Wu,Conghui Liu,Danni Zheng,Congzhi Yan,Wenjing Hu,Xiaohua Zhang,Xuanxuan Dai 한국유방암학회 2022 Journal of breast cancer Vol.25 No.4

Purpose: The incidence rate of breast cancer (BC) has increased annually. Downstream neighbor of son (DONSON) critically affects cell cycle progression and maintains stable genomic properties; however, its relevant effects on BC growth and progression require in-depth investigation. Methods: DONSON upregulation was validated in public databases. DONSON expression in matched BC and adjacent tissues and cell lines (MDA-MB-231, BT-549, and HS-578T) was determined using quantitative reverse transcription polymerase chain reaction. In vitro apoptosis, invasion, migration, and proliferation tests were performed to ascertain the functions of DONSON in BC cell lines. Then, using western blot analysis, the levels of DONSON downstream proteins were determined. Results: Compared to the control, DONSON was expressed at higher levels in BC tissues and cell lines. DONSON knockdown facilitated apoptosis and limited proliferation, migration, invasion, and S/G2 transition of BC cells in vitro. Furthermore, DONSON overexpression promoted BC cell proliferation and inhibited apoptosis in vitro. Moreover, DONSON knockdown reduced cyclin A1 and cyclin-dependent kinase 2 levels. Moreover, DONSON knockdown limited the progression of epithelial-mesenchymal transition. Conclusion: DONSON critically affects BC growth and serves as a possible target and marker for the efficacy of subsequent therapies.

Analysis of the Residual Stress in Zirconium Subjected to Surface Severe Plastic Deformation

Yaomian Wang,Huanping Yang,Conghui Zhang,Fei Yu 대한금속·재료학회 2015 METALS AND MATERIALS International Vol.21 No.2

The residual stress of commercially pure zirconium specimens subjected to surface mechanical attritiontreatment (SMAT) for different durations is measured with X-ray diffraction (XRD). XRD peak broadeninganalysis is conducted to obtain the distributions of the crystallite size, microstrain and dislocation densityas functions of the depth from the processed surface. Finite element modeling is performed to revealthe characteristics of the residual stress distribution. Microstructure observation using optical and electronmicroscopy are also carried out in order to elucidate the residual stress development. The correlationsbetween the microstructure features and the residual stress distribution in zirconium are examined. Theresults indicate that a more pronounced compressive residual stress field can be generated by the SMATprocess compared to that obtained by conventional shot peening, and that the compressive residual stressdistributions exhibit nonlinear variation with the distributions of the full width at the half maximum of theXRD profiles and the dislocation densities.