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Open access

X. Li, W. Zhou, L. Han, W.J. Xi and Garmondyu E. Crusoe

Abstract

To probe into the pattern in which the excavation and loading process have on such factors as stress and displacement in neighboring regions of deep open pits, a mechanical unloading model in coal mining process and another model for the loading process are set up respectively. Besides, FLAC3D software is used to simulate dynamic excavating and loading process in open pits and record such data as the unbalanced stress, unloading strength and displacement fluctuations, which further serve as basis for studying the functional relationship about different mining heights and scope of influence using fitting method. The research results indicate that the unloading strength enhances with increasing mining depth in a linear fashion. In addition, a noticeable displacement circle takes shape around the stope, which would also extends with growing mining depth. As to waste loading, it brings about large-scale surface subsidence in neighboring regions, which follows a logarithm function convergence pattern with the distance away from the dump border. Under combined effects of excavation and loading, the value of the soil mass displacement would increase with growing mining depth and loading height. Specifically, the soil displacement at a distance of 100 m away from the stope border (around 200 m away from the outer dump border) is abnormally significant and it further develops at a rate of 0.0228 mm/h.

Open access

W. Zhou, F. Cai, G. Zhi and B. Mei

Abstract

Highly-transparent trivalent erbium ion doped calcium fluoride (5 mol % Er:CaF2) ceramics were fabricated by a hotpressing (HP) method using high-purity Er:CaF2 nanoparticles, which were synthesized by co-precipitation method. The mean grain size of the nanoparticles was about 24.7 nm. The nanoparticles were sintered at 600 °C, 700 °C, 800 °C and 900 °C, respectively, for 30 min under a uniaxial pressure of 30 MPa and vacuum of 10−3 Pa with 1 mol % lithium fluoride (LiF) as sintering additive. The 5 mol % Er:CaF2 ceramics sintered at 800 °C exhibits high density and pore-free microstructure with an average grain size of about 8 μm. The optical transmittance of the transparent ceramics is close to 85 % at visible and nearinfrared wavelengths. The strong and broad absorptions peaks corresponding to characteristic absorption of trivalent erbium ions make the ceramics a potential candidate for infrared and upconversion laser operating.

Open access

Michael W. Jakowec, Zhou Wang, Daniel Holschneider, Jeff Beeler and Giselle M. Petzinger

Abstract

Exercise and physical activity are fundamental components of a lifestyle essential in maintaining a healthy brain. This is primarily due to the fact that the adult brain maintains a high degree of plasticity and activity is essential for homeostasis throughout life. Plasticity is not lost even in the context of a neurodegenerative disorder, but could be maladaptive thus promoting disease onset and progression. A major breakthrough in treating brain disorders such as Parkinson’s disease is to drive neuroplasticity in a direction to improve motor and cognitive dysfunction. The purpose of this short review is to present the evidence from our laboratories that supports neuroplasticity as a potential therapeutic target in treating brain disorders. We consider that the enhancement of motor recovery in both animal models of dopamine depletion and in patients with Parkinson’s disease is optimized when cognitive circuits are engaged; in other words, the brain is engaged in a learning modality. Therefore, we propose that to be effective in treating Parkinson’s disease, physical therapy must employ both skill-based exercise (to drive specific circuits) and aerobic exercise (to drive the expression of molecules required to strengthen synaptic connections) components to select those neuronal circuits, such as the corticostriatal pathway, necessary to restore proper motor and cognitive behaviors. In the wide spectrum of different forms of exercise, learning as the fundamental modality likely links interventions used to treat patients with Parkinson’s disease and may be necessary to drive beneficial neuroplasticity resulting in symptomatic improvement and possible disease modification.

Open access

W. Yang, H. Xiu, Y. Xiong, J. Wang, C. Yuan, J. Wei and Z. Zhou

Abstract

(Na0.52K0.44Li0.04)0.97La0.01Ta0.20Nb0.80O3 (KNLTN-La0.01) lead-free subtransparent ceramics was prepared by a conventional sintering technique. The structure and the optical properties of the ceramics were investigated. The room temperature crystallographic indexing revealed the ABO3 perovskite type, tetragonal phase and P4mm point group in the ceramics. The surface and fractured surface SEM micrographs showed a dense microstructure with few micropores in KNLTN-La0.01 ceramics, which was obviously better than for the pure KNLTN ceramics. The refractive indexes of the films were investigated by an ellipsometer and the results show that the KNLTN-La0.01 subtransparent ceramics reveals significant wavelength dependent dispersion. The refractive index ranges from 2.14 to 2.06 with the wavelength increase from 380 nm to 900 nm. The dispersive behavior was analyzed by three parameters of Cauchy dispersion model and the values of the parameters A, B and C are 2.0610±0.0005, 0.0054±0.0003 and 0.00069±0.00004, respectively.

Open access

X.J. Chen, X.Q. Zhang, S. Huang, Z.J. Cao, Q.W. Qin, W.T. Hu, Y. Sun and Y.C. Zhou

Abstract

Golden pompano (Trachinotus ovatus) is an important economically fish species. In this study, with an aim to identify reliable reference genes for quantitative real-time PCR (qRT-PCR) in golden pompano, we evaluated the expression stability of eight housekeeping genes in the presence and absence of poly I:C stimulation in eight tissues. The PCR data was analyzed by geNorm and NormFinder algorithms. The results showed that the expression of all the examined genes exhibited tissue-dependent variations. When under normal physiological condition, geNorm and NormFinder identified B2M and 18S as suitable genes. When studying gene expression under conditions of poly I:C stimulation, the selection of the internal controls should be selected on a tissue basis. At 12 h stimulation, geNorm ranked Actin/UBCE, Actin/B2M, UBCE/B2M, Actin/UBCE, RPL13/B2M, UBCE/GAPDH, B2M/RPL13, and UBCE/B2M, respectively, as the most stably expressed genes in liver, spleen, kidney, gill, intestine, heart, muscle, and brain. Comparable ranking orders were produced by NormFinder. Similar results were obtained at 48 h stimulation. Taken together, these results indicate that B2M and 18S are the most stable gene across tissue types under normal physiological conditions. However, during poly I:C stimulation, no single gene or single pair of genes in the examined set of housekeeping genes can serve as a universal reference across all tissue types. If one gene is preferred, B2M, B2M, UBCE, Actin, B2M/RPL13, B2M, B2M, and RPL13 may be used in spleen, kidney, liver, gill, intestine, brain, muscle, and heart of golden pompano, respectively.