Effect of Li Content on the Surface Film Formed on the Binary Mg–Li Alloys in NaCl Solution

Chuanqiang Li,Dahui Liang,Yejia Lin,Yong Dong,Binqing Shi,Changjian Yan,Zhengrong Zhang 대한금속·재료학회 2024 METALS AND MATERIALS International Vol.30 No.1

The surface film formed on the Mg–Li alloys with different Li content in 0.1 M NaCl solution were investigated via electrochemicaltesting, morphologies observation and chemical composition analysis in this work. The results revealed that thesurface film of Mg–14Li alloy (L14: body centred cubic (BCC)) possessed higher electrical resistivity and remained a highertolerating over-potential (0.1 V vs. open circuit potential) than those of Mg–4Li (L4: hexagonal closed-packed (HCP)) andMg–7.5Li (L7: HCP+BCC), resulting in a better corrosion performance. After 24 h immersion in NaCl solution, the wholesurface film of L14 remained undamaged and displayed weave-like and dense characteristic, while both L4 and L7 present aseverely damaged film. The cross-sectional details illustrated typical two layers of surface film formed on L14 with the outerlayer of ~ 1.5 μm and inner layer of ~ 2.5 μm in thickness, whilst only one layer of film with less than 2.5 μm in thicknesswas observed on L4 and L7. At last, combining analysis of X-ray diffraction, energy dispersive X-ray spectrometry, X-rayphotoelectron spectroscopy and transmission electron microscope confirmed the composition of outer layer of surface filmon the L14 contains much more Mg(OH)2 and Li-containing compounds, and the porous Mg(OH)2 film can be sealed by theLi-containing compounds, which is very different the single Mg(OH)2 film on the traditional magnesium and L4/L7 alloys. As a result, the best protective function of the surface film on the L14 alloy contribute to its high corrosion resistance.

Realgar transforming solution-induced differentiation of NB4 cell by the degradation of PML/RARa partially through the ubiquitin–proteasome pathway

Yang Hai,Xin Wang,Peng Song,Jian-yin Li,Longhe Zhao,Fei Xie,Xiang-min Tan,Qin-Jian Xie,Lan Yu,Yang Li,Zhengrong Wu,Hong Yu Li 대한약학회 2019 Archives of Pharmacal Research Vol.42 No.8

PML/retinoic acid receptor alpha (RARa), as ahallmark of acute promyeloid leukemia (APL), is directlyrelated to the outcome of clinical APL remedy. It isreported that arsenicals can effectively degrade PML/RARa, such as arsenic trioxide and realgar. However, thehigh toxicity or insolubility have hampered their clinicalapplications. Realgar transforming solution (RTS) wasproduced from realgar by bioleaching process in our lab. Previous studies demonstrated that RTS had a significantanti-cancer ability on chronic myeloid leukemia throughoncoprotein degradation. The capacity of RTS on treatingAPL is what is focused on in this study. The results showedthat RTS had a noticeable sensitivity in NB4 cell, and RTSremarkably down-regulated PML/RARa expression andinduced cell differentiation. Further, RTS could accumulatePML/RARa into the nuclear bodies and then executedegradation, which could be reversed by proteasomeinhibitor MG132. The results also exhibited that thereduction of RTS-induced PML/RARa expression accompaniedby the elevation of ubiquitin and SUMO-1 proteinexpression. Finally, PML and SUMO-1 had been demonstratedto be co-localized after RTS treatment byimmunofluorescence co-localization assay and immunoprecipitationassay. In conclusion, these results suggestedthat RTS-induced cell differentiation may attribute to thePML/RARa degradation partially through the ubiquitin–proteasome pathway.

Influence of Variable Air Gap on the Electromagnetic Performances of Permanent Magnet Brushless DC Motor

Zhengrong Wang,Rennian Li,Gaoping Xu,Wei Han,Mingkuo Bian,Weiwei Zhou,Qinjiang Sun 한국유체기계학회 2021 International journal of fluid machinery and syste Vol.14 No.4

Simulation models of permanent magnet brushless DC motor with cam rotors and two kinds of uniform air gap motor determined by two limit arcs of the cam rotor were established on the basis of JMAG software. These simulation models were used to determine the influence of regularly varying air gap, which is formed during the rotation of the two cam rotors of the hydraulic motor pumps integrated with a cam rotor vane pump and a permanent magnet brushless DC motor, on the electromagnetic performance of the motor. The electromagnetic performance of the three kinds of motors were simulated and compared under rated and variable loads, respectively. Finally, the cam rotor motor prototype was developed for experimental research. Results show that the starting time of cam rotor motor under rated load is 20% shorter, and its output torque ripple is 23% smaller than those of the uniform air gap motor determined by the minimum limit arc of the cam rotor. However, the air gap flux density curve of the cam rotor motor weakens obviously amongst the three motors. Under different loads, the efficiency of the cam rotor motor is the highest amongst the three motors, and its mechanical property is hard. The research results can lay a theoretical foundation for the development of cam rotor motor pumps.

Mixed L/l₁Fault Detection Observer Design for Positive Switched Systems with Time-varying Delay via Delta Operator Approach

Shuo Li,Zhengrong Xiang,Hamid Reza Karimi 제어·로봇·시스템학회 2014 International Journal of Control, Automation, and Vol.12 No.4

This paper investigates the problem of fault detection observer design for positive switched systems with time-varying delay via delta operator approach. A new fault sensitivity measure, called l– index, is proposed. The l– fault detection observer design and multi-objective l– /l1 fault detection observer design problems are addressed. Based on the average dwell time approach and the piecewise co-positive type Lyapunov-Krasovskii functional method in delta domain, sufficient conditions for the existence of such two kinds of fault detection observers are firstly given, and then the design methods are presented. Finally, two examples are provided to show the effectiveness and the applicability of the proposed methods.

Acoustic Noise of Brushless DC Motors Induced by Electromagnetic Torque Ripple

Kun Xia,Zhengrong Li,Jing Lu,Bin Dong,Chao Bi 전력전자학회 2017 JOURNAL OF POWER ELECTRONICS Vol.17 No.4

Torque ripple is one of the major sources inducing vibration and noise in brushless DC motors. This is especially true in applications such as the spindle motors used in hard disk drives. However, the relationship between torque ripple and acoustic noise/vibration is quite complicated. This paper presents a way to investigate this relationship with acoustic noise measurement and analysis. Results obtained with three different drive modes are used in the analysis. The results show that the acoustic noise analysis is very helpful in designing a high-performance drive strategy for BLDC motors.

Acoustic Noise of Brushless DC Motors Induced by Electromagnetic Torque Ripple

Xia, Kun,Li, Zhengrong,Lu, Jing,Dong, Bin,Bi, Chao The Korean Institute of Power Electronics 2017 JOURNAL OF POWER ELECTRONICS Vol.17 No.4

Torque ripple is one of the major sources inducing vibration and noise in brushless DC motors. This is especially true in applications such as the spindle motors used in hard disk drives. However, the relationship between torque ripple and acoustic noise/vibration is quite complicated. This paper presents a way to investigate this relationship with acoustic noise measurement and analysis. Results obtained with three different drive modes are used in the analysis. The results show that the acoustic noise analysis is very helpful in designing a high-performance drive strategy for BLDC motors.

Antidiabetic Effects of Corni Fructus Extract in Streptozotocin-Induced Diabetic Rats

Dawei Gao,Qingwang Li,Zhengrong Gao,Lixin Wang 연세대학교의과대학 2012 Yonsei medical journal Vol.53 No.4

Purpose: Diabetes is the leading cause of end-stage renal failure. The present study was undertaken to characterize the effects of Corni Fructus on diabetic nephropathy in streptozotocin-induced diabetic rats and their mechanisms. Materials and Methods:Streptozotocin-diabetic rats were orally administrated with Corni Fructus at a dose of 100, 200 or 400 mg/kg body mass for 40 days. Results: Corni Fructus-treated diabetic rats showed significant decreases of blood glucose, urinary protein levels and water consumption. Corni Fructus also reduced serum total cholesterol, total triglyceride and low-density lipoprotein cholesterol levels, and showed a tendency of enhancing high-density lipoprotein cholesterol level. Levels of serum albumin and creatinine in diabetic rats were also significantly reduced by Corni Fructus administration at a dose of 200 and 400 mg/kg body mass compared with non-treated diabetic rats. Corni Fructus increased catalase (CAT), superoxide dismutase (SOD) and glutathione peroxidose (GSH-px) activities in the kidneys of diabetic rats. Furthermore, Corni Fructus treatment enhanced renal peroxisome proliferator-activated receptor-γ (PPARγ) expression in diabetic rats. Conclusion: These results demonstrated that Corni Fructus may have the potential to protect the animals from diabetic nephropathy by amelioration of oxidative stress and stimulation of PPARγ expression.

Analysis on Development Countermove in Nantong

Wenzheng Yu,Tianliang Chen,Qi Ying Xiang,Li Shao,Zhengrong Huang 보안공학연구지원센터(IJUNESST) 2014 International Journal of u- and e- Service, Scienc Vol.7 No.2

Optimizing bioconversion of ferulic acid to vanillin by Bacillus subtilis in the stirred packed reactor using Box-Behnken design and desirability function

Peng Chen,Lei Yan,Shuang Zhang,Zhengrong Wu,Suyue Li,Xiaojuan Yan,Ningbo Wang,Ning Liang,Hong Yu Li 한국식품과학회 2017 Food Science and Biotechnology Vol.26 No.1

A stirring bioreactor packed with a carbon fiber textiles (FT) biofilm formed by Bacillus subtilis was used to produce vanillin from ferulic acid. Biofilm formation was characterized by scanning electron microscopy. The interactive effects of three variables on vanillin molar yield (M) and conversion efficiency of ferulic acid (E) were evaluated by response surface methodology (RSM) with a Box-Behnken design (BBD). The optimal conversion conditions with a maximum overall desirability D of 0.983 were obtained by a desirability function. Considering the actual operation, the confirmation tests were performed using the slightly modified optimal conditions (initial ferulic acid concentration 1.55 g/ L, temperature 35oC, stirring speed 220 rpm). The results showed that M and E were 57.42 and 93.53%, respectively. This was only 1.03% and 1.87%, respectively, different from the predicted values, confirming the validity of the predicted models. These revealed that the stirred packed reactor could be successfully used in vanillin bioconversion from ferulic acid.

Microstructure Evolution and Mechanical Properties of Ultra-Fine Grain AlCrFe2Ni2Wx High-Entropy Alloys

Shougang Duan,Yufeng Yang,Yong Dong,Yu Wang,Beibei Jiang,Chuanqiang Li,Zhengrong Zhang 대한금속·재료학회 2023 METALS AND MATERIALS International Vol.29 No.6

Ultra-fine grain AlCrFe2Ni2Wx(x = 0.1, 0.2, 0.3, 0.4) alloys were designed and prepared by vacuum arc melting, and correspondingmicrostructural evolution and mechanical properties were investigated. All of the alloys show a mixed structurewith FCC + BCC (B2) + TCP phases. The addition of W element has a significant effect on the formation mechanism of themorphology, which promotes the transition from FCC phase to μ phase and inhibits the spinodal decomposition of BCCphase. With the increase of W content, more μ phase precipitates from the FCC phase and grain boundaries. After the dissolutionof W element into matrix, the formed oversaturated solid solution and precipitated μ phase have the effect of solidsolution strengthening and second phase strengthening, respectively. The yield strength and Vickers hardness increasesfrom 765 to 1319.6 MPa and HV 332.2 to HV 461.8, respectively. The addition of W element enhances the strength of thealloys but reduced ductility. The AlCrFe2Ni2W0.1alloy exhibits outstanding comprehensive mechanical properties, with itsfracture strength reaching 2726.5 MPa and a considerable compressive strain of 43.3%, which implies promising potentialengineering application.