Non-resonant 3D Elliptical Vibration Cutting Induced Submicron Grating Coloring

Jianzhong Chen,Mingming Lu,Jieqiong Lin,Jiakang Zhou,Xifeng Fu,Xiaoqin Zhou 한국정밀공학회 2021 International Journal of Precision Engineering and Vol.22 No.4

Surface Submicron grating manufacturing has broad application prospects, which has also been the subject of intensive research and development by scholars with many eff orts. In this paper, a grating coloring manufacturing method is proposed based on three-dimensional elliptical vibration cutting and non-resonant piezoelectric actuator. Based on the mechanism of elliptical motion, an effective cutting depth model was established. Nonlinear interaction of machining parameters (overlap rate, nominal cutting speed, vibration frequency) on the geometry of the grating were analyzed and controllable modulation model of grating geometry was established. The geometrical dimensions of the grating were predicted and grooved experiments were performed on brass and aluminum surfaces. A set of angle-adjustable detection device was designed independently to check the diffraction quality of the grating. The quantitative experimental results show that grating distances of copper and aluminum rods are 752 nm and 684 nm, respectively. The average width of the aluminum rod overall grating is 764 nm, the accuracy error is 9.25%. In addition, aluminum rod gratings can diffractred light at non-specific angles, which is more effective at viewing angle of 70°. The experimental results are in agreement with the theory which have positive significance for expanding the functional surface.

Mechanical Stimulation and Diameter of Fiber Scaffolds Affect the Differentiation of Rabbit Annulus Fibrous Stem Cells

Zhou Pinghui,Wei Bangguo,Guan Jingjing,Chen Yu,Zhu Yansong,Ye Yuchen,Meng Yue,Guan Jianzhong,Mao Yingji 한국조직공학과 재생의학회 2021 조직공학과 재생의학 Vol.18 No.1

BACKGROUND: Degeneration of the annulus fibrosus (AF), an important structure of the intervertebral disc, is one of the main causes of degenerative disc disease. Fabrication of scaffolds replicating the stratified microstructure of the AF is critical for the successful regeneration of AF. METHODS: In this study, we cultured rabbit AF-derived stem cells (AFSCs) using fabricated electrospun fibrous poly-L-lactic acid scaffolds with different diameters. We applied cyclic tensile strain (CTS) on the scaffolds to regulate the differentiation of AFSCs into specific cell types that resided at the inner, middle, and outer zones of the AF. RESULTS: We found that the morphologies of AFSCs on the smaller-fiber-diameter scaffolds were nearly round, whereas spindle-like cells morphologies were observed on large-diameter scaffolds. CTS enhanced these phenomena and made the cells slender. The expression levels of collagen-I in cells increased as a function of the fiber diameter, whereas collagen-II and aggrecan exhibited opposite trends. Moreover, the application of CTS upregulated the gene expressions of collagen-I, collagen-II, and aggrecan. CONCLUSION: Overlaying the scaffolds with different CTS-stimulated cells could eventually lead to engineered AF tissues with hierarchical structures that approximated the native AF tissue. Thus, the proposed methodologies could be potentially applied for AF regeneration. BACKGROUND: Degeneration of the annulus fibrosus (AF), an important structure of the intervertebral disc, is one of the main causes of degenerative disc disease. Fabrication of scaffolds replicating the stratified microstructure of the AF is critical for the successful regeneration of AF. METHODS: In this study, we cultured rabbit AF-derived stem cells (AFSCs) using fabricated electrospun fibrous poly-L-lactic acid scaffolds with different diameters. We applied cyclic tensile strain (CTS) on the scaffolds to regulate the differentiation of AFSCs into specific cell types that resided at the inner, middle, and outer zones of the AF. RESULTS: We found that the morphologies of AFSCs on the smaller-fiber-diameter scaffolds were nearly round, whereas spindle-like cells morphologies were observed on large-diameter scaffolds. CTS enhanced these phenomena and made the cells slender. The expression levels of collagen-I in cells increased as a function of the fiber diameter, whereas collagen-II and aggrecan exhibited opposite trends. Moreover, the application of CTS upregulated the gene expressions of collagen-I, collagen-II, and aggrecan. CONCLUSION: Overlaying the scaffolds with different CTS-stimulated cells could eventually lead to engineered AF tissues with hierarchical structures that approximated the native AF tissue. Thus, the proposed methodologies could be potentially applied for AF regeneration.

Microstructure and mechanical properties of Al-Fe-V-Si alloy and composites

BoluXiao,Jianzhong Fan,Lihua Zhou,Likai Shi 한양대학교 세라믹연구소 2006 Journal of Ceramic Processing Research Vol.7 No.2

Al-Fe-V-Si alloy and composites from it were prepared by a powder metallurgy (PM) route as well as by mechanical alloying (MA). Globular particles referred to as α-Al13 consisted of a quaternary silicide of Alx(FeV)ySi and α-AlFeSi diminished after ball milling and grows slightly during the fabrication process. Whereas, the particle in the PM samples grew extensively. For PM samples, the high temperature mechanical strength of the composite is slightly higher than for the unreinforced alloy.

Heterologous Expression of a Gibberellin 2-Oxidase Gene from Arabidopsis thaliana Enhanced the Photosynthesis Capacity in Brassica napus L.

Bo Zhou,Dan Peng,Jianzhong Lin,Xingqun Huang,Wusheng Peng,Reqing He,Ming Guo,Dongying Tang,Xiaoying Zhao,Xuanming Liu 한국식물학회 2011 Journal of Plant Biology Vol.54 No.1

Gibberellins (GAs) are endogenous hormones that play an important role in regulating plant stature by increasing cell division and promoting seed germination. The GA2-oxidase gene from Arabidopsis thaliana (AtGA2ox8) was introduced into Brassica napus L. by Agrobacterium-mediated floral-dip transformation with the aim of decreasing the amount of bioactive GA and hence reduced the plant height. As anticipated, the transgenic plant exhibited dwarf phenotype. Importantly, compared with the wild type, the transgenic plants had delayed the seed germination, increased the chlorophyll content (28.7–36.3%) and photosynthesis capacity (14.3–18.7%) in a single leaf. At the same time, the photosynthesis capacity of the whole plants was significantly enhanced (35.7–48.6%) due to the extra leaves and branches.

Experiments and simulations of the ballistic response of ceramic composite armors

Jinfeng Cao,Jianzhong Lai,Jiehang Zhou,Ningyu Kang,Longyu Du,Yiqiu Miao 대한기계학회 2020 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.34 No.7

A lightweight multilayer ceramic composite armor with a sandwich structure back plate was proposed by studying the penetration process, damage mechanism, and the function of each layer of the composite armor against the 12.7 mm armor-piercing projectile. The effectiveness of the simulation was verified by comparing the experimental and simulation data. The effects of crack initiation in the ceramics, abrasion of ceramics, and size of ceramic cones on the penetration resistance of targets were discussed. The structural configuration of backplate sequence and thickness ratio was optimized through finite element simulation on ANSYS/LS-DYNA. Results indicate that boundary constraints have a significant effect on the antipenetration performance of ceramics. The antipenetration performance is the best when the structure of restrained composite armor is Al6061/Al 2 O 3 /TC4/ Kevlar ® /TC4 and the thickness ratio of the TC4 transition and back plates is 4:3.

Mechanism underlying the effect of conventional drying on the grinding characteristics of Ximeng lignite

Yumeng Yang,Jianzhong Liu,Xiang He,Zhihua Wang,Junhu Zhou,Kefa Cen 한국화학공학회 2017 Korean Journal of Chemical Engineering Vol.34 No.4

Same amounts of moisture were removed from Ximeng lignite (XL) with different particle size ranges pretreated at different drying temperatures. The effect of conventional drying on the grindability of the XLs was investigated. Increasing the drying temperature improved the grindability of all the samples. The results of scanning electron microscopy and mercury intrusion porosimetry revealed that the dominant mechanism enhancing the grindability of XL with high moisture was the pore structure destruction induced by the steam jet flow generated with the removal of moisture. Especially, the development of large fractures had a strong connection with the change in the grindability. According to the pore size distribution, the internal structure of the 2.5-4.0mm coal samples did not develop well under high drying temperature because of the exceedingly short heating time. Therefore, coal particle size, drying temperature, and heating time must be coordinated well to achieve the enhanced drying effect. The grindability of XL had a negative linear correlation with the pore volume fractal dimension, revealing the possibility of fractal dimension for the analysis of lignite grindability.

Effect of post-heat treatment on the microstructure and mechanical properties of laser metal deposition Inconel 718

Pengfei Li,Jianzhong Zhou,Yadong Gong,Xiankai Meng,Jinzhong Lu 대한기계학회 2021 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.35 No.7

The microstructure, hardness, and fracture strength of Inconel 718 fabricated with laser metal deposition are investigated. The solution treatment plus aging (STA) (including 980 °C, 720 °C, and 620 °C for 1, 8, and 8 h, respectively) and low-temperature stress-relief annealing (LTSLA) (including 650 °C for 1 h) are compared, which can respectively improve the hardness and tensile properties. Results show that the as-deposited sample mainly contained γ matrix, coarse Laves phase, granular carbides, and nitrides. STA and LTSLA post-heat treatments could respectively improve the hardness and tensile properties, while the elongation slightly decreased. The solution treatment promoted almost Laves phase to dissolve into γ matrix and homogenized the matrix, and the aging treatment promoted the precipitation of γ′ and γ′′ phases, which significantly improved the mechanical properties.

A Novel ACE Inhibitory Peptide Ala-His-Leu-Leu Lowering Blood Pressure in Spontaneously Hypertensive Rats

Ying Li,Jianzhong Zhou,XiaoXiong Zeng,Jianmei Yu 한국식품영양과학회 2016 Journal of medicinal food Vol.19 No.2

Ala-His-Leu-Leu (AHLL) was isolated and purified from the loach (Misgurnus anguillicaudatus) hydrolysate in our previous study. The aim of this study was to investigate the antihypertensive effects of angiotensin-I-converting enzyme (ACE) inhibitory peptide AHLL in spontaneously hypertensive rats (SHRs). AHLL showed good antihypertensive effects in SHRs during the long-term oral administration and no allergic reactions or coughing were observed. After 2 months of oral administration of AHLL, the body weight growth was normal. The decrements in systolic blood pressure of the high dose (5 mg/kg bw) and the low dose of AHLL (1 mg/kg bw) treatment groups were 22.1 and 5.0mmHg at week 8, respectively. Compared to the control group, the concentrations of triglyceride and sodium in serum were reduced significantly in the highdose group after 2 months. The ACE activity of kidney and lung decreased significantly, which indicated that AHLL exerted an antihypertensive effect on kidney and lung and they were the target sites of AHLL. These results strongly supported the in vivo antihypertensive mechanism of AHLL.

An Adaptive Stopping Active Contour Model for Image Segmentation

Yuefeng Niu,Jianzhong Cao,Zuofeng Zhou 대한전기학회 2019 Journal of Electrical Engineering & Technology Vol.14 No.1

Active contour models (ACMs) are widely used in image segmentation applications. However, the selection of maximum iterations which controls the convergence of the ACMs is still a challenging problem. In this paper, an adaptive method for choosing the optimal number of iterations based on the local and global intensity fitting energy is proposed, which increases the automaticity of the active contour model. Moreover, the adoption of the reaction diffusion (RD) method instead of the distance regularization term can improve the accuracy and speed of segmentation effectively. Experimental results on synthetic and real images show that the proposed model outperforms other representative models in terms of accuracy and efficiency.

A New Iterative LT Decoding Algorithm for Binary and Nonbinary Galois Fields

Yuexin Mao,Jie Huang,Bing Wang,Jianzhong Huang,Wei Zhou,Shengli Zhou 한국통신학회 2013 Journal of communications and networks Vol.15 No.4

Digital fountain codes are record-breaking codes for erasure channels. They have many potential applications in both wired and wireless communications. Most existing digital fountain codes operate over binary fields using an iterative belief-propagation (BP) decoding algorithm. In this paper, we propose a new iterative decoding algorithm for both binary and nonbinary fields. The basic form of our proposed algorithm considers both degree-1 and degree-2 check nodes (instead of only degree-1 check nodes as in the original BP decoding scheme), and has linear complexity. Extensive simulation demonstrates that it outperforms the original BP decoding scheme, especially for a small number of source packets. The enhanced form of the proposed algorithm combines the basic form of the algorithm and a guess-based algorithm to further improve the decoding performance. Simulation results demonstrate that it can provide better decoding performance than the guess-based algorithm with fewer guesses, and can achieve decoding performance close to that of the maximum likelihood decoder at a much lower decoding complexity. Last, we show that our nonbinary scheme has the potential to outperform the binary scheme when choosing suitable degree distributions, and furthermore it is insensitive to the size of the Galois field.