Free vibration analysis of thin rectangular plates with two adjacent edges rotationally-restrained and the others free using finite Fourier integral transform method

Jinghui Zhang,Jiale Lu,Salamat Ullah,Yuanyuan Gao,Dahai Zhao,Arshad Jamal,Ömer Civalek 국제구조공학회 2021 Structural Engineering and Mechanics, An Int'l Jou Vol.80 No.4

For the first time, the finite Fourier integral transform approach is extended to analytically solve the free vibration problem of rectangular thin plates with two adjacent edges rotationally-restrained and others free. Based on the fundamental transform theory, the governing partial differential equations (PDEs) of the plate is converted to ordinary linear algebraic simultaneous equations without assuming trial function for deflection, which reduces the mathematical complexity caused by both the free corner and rotationally-restrained edges. By coupling with mathematical manipulation, the analytical solutions are elegantly achieved in a straightforward procedure. In addition, the vibration characteristics of plates under classical boundary conditions are also studied by choosing different rotating fixed coefficients. Finally, more than 400 comprehensive analytical solutions were well validated by finite element method (FEM) results, which can be served as reference data for further studies. The advantages of the present method are that it does not need to preselect the deformation function, and it has general applicability to various boundary conditions. The presented approach is promising to be further extended to solve the static and dynamic problems of moderately thick plates and thick plates.

Analysis of orthotropic plates by the two-dimensional generalized FIT method

Jinghui Zhang,Salamat Ullah,Yuanyuan Gao,Mehmet Avcar,Ömer Civalek 사단법인 한국계산역학회 2020 Computers and Concrete, An International Journal Vol.26 No.5

In this study, the two-dimensional generalized finite integral transform(FIT) approach was extended for new accurate thermal buckling analysis of fully clamped orthotropic thin plates. Clamped-clamped beam functions, which can automatically satisfy boundary conditions of the plate and orthogonality as an integral kernel to construct generalized integral transform pairs, are adopted. Through performing the transformation, the governing thermal buckling equation can be directly changed into solving linear algebraic equations, which reduces the complexity of the encountered mathematical problems and provides a more efficient solution. The obtained analytical thermal buckling solutions, including critical temperatures and mode shapes, match well with the finite element method (FEM) results, which verifies the precision and validity of the employed approach.

Numerical investigation on the multiphase flow field at various muzzle velocities

Jinghui Zhang,Yonggang Yu,Xinwei Zhang 대한기계학회 2022 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.36 No.8

To predict the multiphase flow field during the underwater launch, a twodimensional (2D) transient model and a visual experiment platform were employed. The simulated graphs were compared to the experimental photos, and the results indicate the reasonableness of the model. Furthermore, the effects of muzzle velocity on the flow field were investigated. The results demonstrate that a partially formed bottle-shaped shock wave is generated when t = 0.4 ms for various velocities, and a greater muzzle velocity can accelerate its expansion process. Additionally, the maximum displacement of the Mach disk fulfills the binomial law with the muzzle velocity. The maximum peak pressure of oscillations increases with the greater muzzle velocity, but the duration of pressure oscillations decreases.

Selective deposition of Au-Pt alloy nanoparticles on ellipsoidal zirconium titanium oxides for reduction of 4-nitrophenol

Zewu Zhang,Jinghui Zhang,Guangqing Liu,Mengwei Xue,Zhangzhong Wang,Xiaohai Bu,Qiong Wu,Xuejuan Zhao 한국화학공학회 2017 Korean Journal of Chemical Engineering Vol.34 No.9

Au-Pt alloy nanoparticles that are selectively anchored on TiO2 surface of the ellipsoidal zirconium titanium composite oxides were successfully prepared by a facile two-step method: prefabricated binary composite oxides on the ellipsoidal Fe2O3@SiO2 by a versatile cooperative template-directed coating method, and then in situ formation of Au-Pt alloy NPs with Sn2+ as the reduction agent. The alloy catalysts were characterized by X-ray diffraction, transmission electron microscopy and X-ray photoelectron spectroscopy. The result suggested that highly dispersive and ultrafine Au-Pt alloy nanoparticles were deposited onto TiO2 surface of the binary oxides solely. The particle size of nanoalloys was closely related to the ratio of Zr : Ti in the composite oxides shell. Increasing the content of Zr element led to a growth in the size of alloy nanoparticles. When used as catalysts for the reduction of 4-nitrophenol, the prepared supported alloyed catalysts exhibited high catalytic activity, and the sample could be easily recycled without a significant decrease of the catalytic activity.

Characterization and performance of SmxA1xMnO3 (A=Ce, Sr, Ca) perovskite for efficient catalytic oxidation of toluene

Jinghui Yao,Jiabin Zhou,Tianlei Zhang,Su Liu,Ke Du 한국화학공학회 2022 Korean Journal of Chemical Engineering Vol.39 No.11

Catalytic oxidation of toluene was implemented over SmMnO3, Sm0.8A0.2MnO3 (ABO3, A=Ce, Sr, Ca) and Sm1xCaxMnO3 (x=0.0, 0.1, 0.2, 0.3) perovskite oxides synthesized via sol-gel method. The effects of A-site substitution of SmMnO3 and the amount of calcium substitution of SmMnO3 perovskite-type catalyst on the catalytic activity of toluene were investigated in a fixed bed reactor. The structure and chemical properties of the perovskites were studied by XRD, SEM, XPS, and H2-TPR. The results showed that the substitution of Ce and Ca had a positive impact about the catalytic properties of toluene oxidation, while a negative impact was caused by the substitution of Sr. The catalytic activity of toluene oxidation followed the order of Sm0.8Ca0.2MnO3>Sm0.8Ce0.2MnO3>SmMnO3>Sm0.8Sr0.2MnO3 in terms of the temperature of T90%, at toluene concentration=1,000 ppm and weight hourly space velocity (WHSV)=3,000mL/ g·h. Sm0.8Ca0.2MnO3 had the highest catalytic capacity (T90%=238 oC), which could be attributed to its high adsorbed oxygen concentration, Mn4+/Mn3+, and the best low-temperature reducibility (H2 consumption=0.36). Meanwhile, the Sm0.8Ca0.2MnO3 catalysts showed great long-term stability after 30 h of the reaction, and the toluene degradation rate remained over 95% at 350 oC.

Evolution in Microstructures and Mechanical Properties of Pure Copper Subjected to Severe Plastic Deformation

Mingya Zhang,Li Liu,Shan Liang,Jinghui Li 대한금속·재료학회 2020 METALS AND MATERIALS International Vol.26 No.10

Considering the great advantage of improving the pressing speed in reducing the number of repeated deformation passes andgrain size, high-speed equal channel angular pressing (ECAP) technology has been applied to achieve the perfect distributionof grain size in a sample volume of pure copper. The microstructures and mechanical properties of pure copper sufferingECAP are investigated. The results show that the well refined grains are obtained through three stages, during which the grainreorientation and recrystallization occurs. After ECAP, the volume fraction of high-angle grain boundaries is reduced, butshows an obvious increase in the population for high-pass extruded sample. Besides, ECAP can significantly increase theproportion of the special boundaries probably through the transformation from annealing twins to deformation twins. Thetensile strength of ECAP-ed sample greatly increased to 1.87 times larger than that of the annealed bar, and then improvedslowly regardless of increasing strain. The relationship between strength and grain size still obeyed Hall–Petch formula. The cloud maps of microhardness distribution illustrated that the hardness is severely improved after the first three passes,but leveled off after that. Besides, the cloud maps also present the moderate inhomogeneity of microhardness with highervalues in the edge and lower values towards the center.

Accurate buckling analysis of rectangular thin plates by double finite sine integral transform method

Salamat Ullah,Jinghui Zhang,Yang Zhong 국제구조공학회 2019 Structural Engineering and Mechanics, An Int'l Jou Vol.72 No.4

This paper explores the analytical buckling solution of rectangular thin plates by the finite integral transform method. Although several analytical and numerical developments have been made, a benchmark analytical solution is still very few due to the mathematical complexity of solving high order partial differential equations. In solution procedure, the governing high order partial differential equation with specified boundary conditions is converted into a system of linear algebraic equations and the analytical solution is obtained classically. The primary advantage of the present method is its simplicity and generality and does not need to pre-determine the deflection function which makes the solving procedure much reasonable. Another advantage of the method is that the analytical solutions obtained converge rapidly due to utilization of the sum functions. The application of the method is extensive and can also handle moderately thick and thick elastic plates as well as bending and vibration problems. The present results are validated by extensive numerical comparison with the FEA using (ABAQUS) software and the existing analytical solutions which show satisfactory agreement.

A non-invasive approach to investigation of ventricular blood pressure using cardiac sound features

Tang, Hong,Zhang, Jinghui,Chen, Huaming,Mondal, Ashok,Park, Yongwan IOP PUBLISHING 2017 PHYSIOLOGICAL MEASUREMENT Vol. No.

<P>Heart sounds (HSs) are produced by the interaction of the heart valves, great vessels, and heart wall with blood flow. Previous researchers have demonstrated that blood pressure can be predicted by exploring the features of cardiac sounds. These features include the amplitude of the HSs, the ratio of the amplitude, the systolic time interval, and the spectrum of the HSs. A single feature or combinations of several features have been used for prediction of blood pressure with moderate accuracy.</P> <P>Experiments were conducted with three beagles under various levels of blood pressure induced by different doses of epinephrine. The HSs, blood pressure in the left ventricle and electrocardiograph signals were simultaneously recorded. A total of 31 records (18 262 cardiac beats) were collected. In this paper, 91 features in various domains are extracted and their linear correlations with the measured blood pressures are examined. These features are divided into four groups and applied individually at the input of a neural network to predict the left ventricular blood pressure (LVBP).</P> <P>The analysis shows that non-spectral features can track changes of the LVBP with lower standard deviation. Consequently, the non-spectral feature set gives the best prediction accuracy. The average correlation coefficient between the measured and the predicted blood pressure is 0.92 and the mean absolute error is 6.86 mmHg, even when the systolic blood pressure varies in the large range from 90 mmHg to 282 mmHg.</P> <P>Hence, systolic blood pressure can be accurately predicted even when using fewer HS features. This technique can be used as an alternative to real-time blood pressure monitoring and it has promising applications in home health care environments.</P>

Streptococcus pneumoniae aminopeptidase N contributes to bacterial virulence and elicits a strong innate immune response through MAPK and PI3K/AKT signaling

Ling Wang,Xuemei Zhang,Guangying Wu,Yuhong Qi,Jinghui Zhang,Jing Yang,Hong Wang,Wenchun Xu 한국미생물학회 2020 The journal of microbiology Vol.58 No.4

Streptococcus pneumoniae is a Gram-positive pathogen with high morbidity and mortality globally but some of its pathogenesis remains unknown. Previous research has provided evidence that aminopeptidase N (PepN) is most likely a virulence factor of S. pneumoniae. However, its role in S. pneumoniae virulence and its interaction with the host remains to be confirmed. We generated a pepN gene deficient mutant strain and found that its virulence for mice was significantly attenuated as were in vitro adhesion and invasion of host cells. The PepN protein could induce a strong innate immune response in vivo and in vitro and induced secretion of IL-6 and TNF-α by primary peritoneal macrophages via the rapid phosphorylation of MAPK and PI3K/AKT signaling pathways and this was confirmed using specific pathway inhibitors. In conclusion, PepN is a novel virulence factor that is essential for the virulence of S. pneumoniae and induces host innate immunity via MAPK and PI3K/AKT signaling.

Brief introduction of geology in North Korea

Mingguo Zhai,Xiao-Hui Zhang,Yan-Bin Zhang,Peng Peng,Qiu-Li Li,Jinghui Guo,Tie-Sheng Li,Lei Zhao,Li-Gang Zhou,Xiyan Zhu 대한지질학회 2019 대한지질학회 학술대회 Vol.2019 No.10