Study on Wear Prediction of Shield Disc Cutter in Hard Rock and Its Application

Zhenyong Wang,Chenglong Liu,Yusheng Jiang,Linwei Dong,Shixian Wang 대한토목학회 2022 KSCE JOURNAL OF CIVIL ENGINEERING Vol.26 No.3

It is important to enable the prediction of disc cutter wear during shield tunnelling through hard rock because such wear is associated with project delays and increased costs. Based on a theoretical analysis of Archard’s wear mechanism and Euler’s rotation theorem, a displacement equation of rock-breaking point A on the disc cutter ring is studied, and then a new wear prediction model is established combined with the theoretical analysis of the disc cutter force and wear test. The cutter wear prediction model is verified by using the data of two cases, and the results reveal that the errors between measured and predicted values are less than 25%. The research results also show that abrasive wear is the main wear mechanism (approximately 88%). In addition, the influence of fatigue wear is very small, accounting for only approximately 2%, which can be ignored. Finally, the maximum tunneling distance of disc cutters under different installation radii and penetration is studied using the model, and the results can be used as references for optimizing shield tunneling parameters and predicting the disc cutter replacement time.

Research Progress in SiC-Based Ceramic Matrix Composites

Dong, Shaoming,Wang, Zhen,Zhou, Haijun,Kan, Yan-Mei,Zhang, Xiangyu,Ding, Yusheng,Gao, Le,Wu, Bin,Hu, Jianbao The Korean Ceramic Society 2012 한국세라믹학회지 Vol.49 No.4

SiC-based ceramic matrix composites show many advantages over their monolithic ceramic counterparts, which makes them potential candidates for applications in various fields. Depending strongly on the chemical composition and microstructure of the fiber reinforcement, matrix as well as the fiber/matrix interphase in the material, the properties of ceramic matrix composites(CMCs) are highly tailorable. In this paper, the latest progresses in the interphase design, matrix modification and fiber reinforcement decoration of CMCs are reviewed, their effects on the properties of the CMCs are introduced.

Research Progress in SiC-Based Ceramic Matrix Composites

Shaoming Dong,Zhen Wang,Haijun Zhou,Yan-Mei Kan,Xiangyu Zhang,Yusheng Ding,Le Gao,Bin Wu,Jianbao Hu 한국세라믹학회 2012 한국세라믹학회지 Vol.49 No.4

SiC-based ceramic matrix composites show many advantages over their monolithic ceramic counterparts, which makes them potential candidates for applications in various fields. Depending strongly on the chemical composition and microstructure of the fiber reinforcement, matrix as well as the fiber/matrix interphase in the material, the properties of ceramic matrix composites(CMCs) are highly tailorable. In this paper, the latest progresses in the interphase design, matrix modification and fiber reinforcement decoration of CMCs are reviewed, their effects on the properties of the CMCs are introduced.

Self-Adaptive Power Flow Optimization Method for Multi-Terminal SNOP Considering the Difference of Risk of Node Voltage beyond Limit

Yiming Xu,Zhiqiang Wang,Zheng Fang,Sichao Xun,Guirong Hu,Yusheng Shen,Hongyi Xiao,Dongning Wu 대한전기학회 2019 Journal of Electrical Engineering & Technology Vol.14 No.5

Soft Normally Open Point (SNOP) is a power electronic device used widely in power distribution network. It can solve many problems by adjusting reactive power compensation and active power transmission. The uncertainty and fluctuation of distributed generation (DG) may cause many problems to the distribution network. In order to balance the safety and economy in power flow optimization better, a self-adaptive power flow optimization method for active distribution network with multi-terminal SNOP considering difference of the risk of node voltage beyond limit is put forward. It takes both weighted voltage deviation and the network loss into objective function to construct the optimal operation model and mainly has two improvements: one is considering initial voltage deviation and real-time penetration of the DG to establish the self-adaptive weight model of the sum of voltage deviation in the objective function; the other is putting forward the weighting strategy for node voltage deviation which decided by the electrical distance, DG position and correlation between source output and load. Then, taking three improved IEEE33 node feeders as an example to verify the validity of the strategy. The results validate that the self-adaptive strategy can reduce the loss and improve the regulation of voltage better and is useful in distribution network under different penetration

Mechanical induced electrical failure of shock compressed PZT95/5 ferroelectric ceramics

Hengchang Nie,Jia Yang,Xuefeng Chen,Fuping Zhang,Yin Yu,Genshui Wang,Yusheng Liu,Hongliang He,Xianlin Dong 한국물리학회 2017 Current Applied Physics Vol.17 No.4

A comparative experimental study of shock compressed Pb0.99(Zr0.95Ti0.05)0.98Nb0.02O3 (hereafter referred to as PZT95/5) ferroelectric ceramics within different insulation materials were performed in this study. It was found that the insulating materials play a significant role in the electrical failure behavior of PZT95/5 ferroelectric ceramic. The electrical breakdown behavior of PZT95/5 ferroelectric ceramics within epoxy resin was observed to aggravate at low temperature 55 C. Porous PZT95/5 ferroelectric ceramic was found to exhibit lower failure probability than its dense counterpart. Electrical failure of PZT95/5 ferroelectric ceramics under shock wave was found to be an extrinsic behavior and a tentative explanation was proposed based on the mechanical compressive stress-induced cracks initiation by epoxy resin.

Lead-free KNbO₃ ferroelectric nanorod based flexible nanogenerators and capacitors

Jung, Jong Hoon,Chen, Chih-Yen,Yun, Byung Kil,Lee, Nuri,Zhou, Yusheng,Jo, William,Chou, Li-Jen,Wang, Zhong Lin IOP Pub 2012 Nanotechnology Vol.23 No.37

<P>In spite of high piezoelectricity, only a few one-dimensional ferroelectric nano-materials with perovskite structure have been used for piezoelectric nanogenerator applications. In this paper, we report high output electrical signals, i.e. an open-circuit voltage of 3.2 V and a closed-circuit current of 67.5 nA (current density 9.3 nA cm<SUP>−2</SUP>) at 0.38% strain and 15.2% s<SUP>−1</SUP> strain rate, using randomly aligned lead-free KNbO<SUB>3</SUB> ferroelectric nanorods (∼1 μm length) with piezoelectric coefficient (d<SUB>33</SUB> ∼ 55 pm V <SUP>−1</SUP>). A flexible piezoelectric nanogenerator is mainly composed of KNbO<SUB>3</SUB>–poly(dimethylsiloxane) (PDMS) composite sandwiched by Au/Cr-coated polymer substrates. We deposit a thin poly(methyl methacrylate) (PMMA) layer between the KNbO<SUB>3</SUB>–PDMS composite and the Au/Cr electrode to completely prevent dielectric breakdown during electrical poling and to significantly reduce leakage current during excessive straining. The flexible KNbO<SUB>3</SUB>–PDMS composite device shows a nearly frequency-independent dielectric constant (∼3.2) and low dielectric loss (<0.006) for the frequency range of 10<SUP>2</SUP>–10<SUP>5</SUP> Hz. These results imply that short and randomly aligned ferroelectric nanorods can be used for a flexible high output nanogenerator as well as high-k capacitor applications by performing electrical poling and further optimizing the device structure. </P>

Oncomodulin/Truncated Protamine-Mediated Nogo-66 Receptor Small Interference RNA Delivery Promotes Axon Regeneration in Retinal Ganglion Cells

Cui, Zhili,Kang, Jun,Hu, Dan,Zhou, Jian,Wang, Yusheng Korean Society for Molecular and Cellular Biology 2014 Molecules and cells Vol.37 No.8

The optic nerve often suffers regenerative failure after injury, leading to serious visual impairment such as glaucoma. The main inhibitory factors, including Nogo-A, oligodendrocyte myelin glycoprotein, and myelin-associated glycoprotein, exert their inhibitory effects on axonal growth through the same receptor, the Nogo-66 receptor (NgR). Oncomodulin (OM), a calcium-binding protein with a molecular weight of an ~12 kDa, which is secreted from activated macrophages, has been demonstrated to have high and specific affinity for retinal ganglion cells (RGC) and promote greater axonal regeneration than other known polypeptide growth factors. Protamine has been reported to effectively deliver small interference RNA (siRNA) into cells. Accordingly, a fusion protein of OM and truncated protamine (tp) may be used as a vehicle for the delivery of NgR siRNA into RGC for gene therapy. To test this hypothesis, we constructed OM and tp fusion protein (OM/tp) expression vectors. Using the indirect immunofluorescence labeling method, OM/tp fusion proteins were found to have a high affinity for RGC. The gel shift assay showed that the OM/tp fusion proteins retained the capacity to bind to DNA. Using OM/tp fusion proteins as a delivery tool, the siRNA of NgR was effectively transfected into cells and significantly down-regulated NgR expression levels. More importantly, OM/tp-NgR siRNA dramatically promoted axonal growth of RGC compared with the application of OM/tp recombinant protein or NgR siRNA alone in vitro. In addition, OM/tp-NgR siRNA highly elevated intracellular cyclic adenosine monophosphate (cAMP) levels and inhibited activation of the Ras homolog gene family, member A (RhoA). Taken together, our data demonstrated that the recombinant OM/tp fusion proteins retained the functions of both OM and tp, and that OM/tp-NgR siRNA might potentially be used for the treatment of optic nerve injury.

Oncomodulin/Truncated Protamine-Mediated Nogo-66 Receptor Small Interference RNA Delivery Promotes Axon Regeneration in Retinal Ganglion Cells

Zhili Cui,Jun Kang,Dan Hu,Jian Zhou,Yusheng Wang 한국분자세포생물학회 2014 Molecules and cells Vol.37 No.8

The optic nerve often suffers regenerative failure after injury, leading to serious visual impairment such as glaucoma. The main inhibitory factors, including Nogo-A, oligodendrocyte myelin glycoprotein, and myelin-associated glycoprotein, exert their inhibitory effects on axonal growth through the same receptor, the Nogo-66 receptor (NgR). Oncomodulin (OM), a calcium-binding protein with a molecular weight of an ~12 kDa, which is secreted from activated macrophages, has been demonstrated to have high and specific affinity for retinal ganglion cells (RGC) and promote greater axonal regeneration than other known polypeptide growth factors. Protamine has been reported to effectively deliver small interference RNA (siRNA) into cells. Accordingly, a fusion protein of OM and truncated protamine (tp) may be used as a vehicle for the delivery of NgR siRNA into RGC for gene therapy. To test this hypothesis, we constructed OM and tp fusion protein (OM/tp) expression vectors. Using the indirect immunofluorescence labeling method, OM/tp fusion proteins were found to have a high affinity for RGC. The gel shift assay showed that the OM/tp fusion proteins retained the capacity to bind to DNA. Using OM/tp fusion proteins as a delivery tool, the siRNA of NgR was effectively transfected into cells and significantly down-regulated NgR expression levels. More importantly, OM/tp-NgR siRNA dramatically promoted axonal growth of RGC compared with the application of OM/tp recombinant protein or NgR siRNA alone in vitro. In addition, OM/tp-NgR siRNA highly elevated intracellular cyclic adenosine monophosphate (cAMP) levels and inhibited activation of the Ras homolog gene family, member A (RhoA). Taken together, our data demonstrated that the recombinant OM/tp fusion proteins retained the functions of both OM and tp, and that OM/tp-NgR siRNA might potentially be used for the treatment of optic nerve injury.