Long X.,Wuhan UniversityHubei |
Liu Q.,Wuhan UniversityHubei |
Ji B.,Wuhan UniversityHubei |
Lu Y.,Wuhan UniversityHubei
International Journal of Heat and Mass Transfer | Year: 2017
Unsteady cavitating turbulent flow in liquid hydrogen around an ogive with consideration of thermodynamic effects is simulated using the modified RNG k-ε turbulence model with a local density correction, the mass transfer homogenous cavitation model coupled with energy equation. The predicted pressure and temperature along the ogive surface agree fairly well with available experimental data. The present study indicates that the thermal cavitation shedding process can be mainly divided into the following three stages: (1) the gradual growth of sheet cavity to its full length, (2) the generation, shedding and collapse of the small cavitation clouds inside the quasi-steady sheet cavity, (3) the formation and collapse of large scale cloud cavity. Further analysis shows that two different mechanisms for maintaining the cavity volume under thermal conditions are illustrated for the sheet/cloud cavitation shedding dynamics, i.e. the small scale cavitation clouds, and the large scale cloud cavity, which has not been reported in isothermal cavitation studies. The cavitation-vortex interaction is further investigated through the assessment of the dilatation and the baroclinic terms in the vorticity transport equation of a variable density flow. It is indicated that the vorticity dilatation is predominant in modulating vorticity inside the large scale cavity and the baroclinic torque mainly accounts for vorticity gradients along the detached cavity surface. An integrated one-dimensional/two-dimensional method is used to study the cavitation excited pressure pulsations on the solid surface. The results show that the pressure oscillations are directly related to the second derivative of the cavity volume and thus demonstrate that the cavity volume acceleration is mainly responsible for the cavitation induced pressure fluctuations. This pressure pulsation mechanism may provide useful information for the development of method for vibration controlling in thermo-sensible fluids applications. © 2017 Elsevier Ltd
Zheng S.,Wuhan UniversityHubei |
Wu B.,Tsinghua University |
Wang K.,Yellow River Institute of Hydraulic Research |
Tan G.,Wuhan UniversityHubei |
And 2 more authors.
International Journal of Sediment Research | Year: 2017
The evolution of the Yellow River delta is characterized by heavy sediment load, rapid seaward migration, frequent avulsions, and intense anthropogenic disturbances. Evolution of the delta channel following avulsions is very complex and has not yet been thoroughly understood. In the research presented by this paper, we conducted comprehensive analyses of the changes in the water stages, slopes, longitudinal profiles, and the erosion and deposition in the Yellow River delta channels during a time period of over five decades. Results showed that, following each avulsion, channels migrated seaward at decaying rates and the slopes at the downstream of the avulsion point decreased exponentially with time and completed its major adjustment within about four to five years. A generalized geometric model was proposed to describe the changes in the longitudinal profiles of the delta channels. A calculation method to determine the characteristic water stages at the delta was proposed based on the geometric model and the delayed response model for the morphological responses of fluvial rivers to perturbations. Water stages corresponding to a discharge of 3000 m3/s at Lijin and Xihekou during 1954 through 2012 were calculated by using the proposed method. The proposed method may be used to predict the evolution of the delta channels in response to artificial avulsions at the Yellow River delta in the future. © 2016 International Research and Training Centre on Erosion and Sedimentation/the World Association for Sedimentation and Erosion Research
Slaunwhite A.K.,University of New Brunswick |
Slaunwhite A.K.,Center for Addictions Research of British Columbia |
Ronis S.T.,University of New Brunswick |
Sun Y.,Wuhan UniversityHubei |
Peters P.A.,University of New Brunswick
Health and Social Care in the Community | Year: 2017
The purpose of this project was to examine the emotional health and well-being of Canadian caregivers of persons with significant mental health or addictions problems. We assessed the emotional health of caregivers by care-receiver condition type (i.e. mental health or addictions vs. physical or other health problems), levels of caregiver stress and methods particularly for reducing stress among caregivers of persons with mental health or addictions disorders. Weighted cross-sectional data from the 2012 General Social Survey (Caregiving and Care Receiving) were modelled using weighted descriptive and logistic regression analyses to examine levels of stress and the emotional health and well-being of caregivers by care-receiver condition type. Caregivers of persons with mental health or addictions problems were more likely to report that caregiving was very stressful and that they felt depressed, tired, worried or anxious, overwhelmed; lonely or isolated; short-tempered or irritable; and resentful because of their caregiving responsibilities. The results of this study suggest that mental health and addictions caregivers may experience disparate stressors and require varying services and supports relative to caregivers of persons with physical or other health conditions. © 2016 John Wiley & Sons Ltd
Huang L.,Nanjing University of Information Science and Technology |
Huang L.,National Center for Space Weather |
Wang J.,National Center for Space Weather |
Jiang Y.,Nanjing University of Information Science and Technology |
And 3 more authors.
Advances in Space Research | Year: 2014
Ionospheric scintillation variations are studied using GPS measurements at the low latitude station of Shenzhen (22.59°N, 113.97°E), situated under the northern crest of the equatorial anomaly region, from the Chinese Meridian Project. The results are presented for data collected during the current phase of rising solar activity (low to high solar activity) from December 2010 to April 2014. The results show that GPS scintillation events were largely a nighttime phenomenon during the whole observation period. Scintillation events mainly occurred along the inner edge of the northern crest of the equatorial anomaly in China. The occurrence of scintillations in different sectors of the sky was also investigated, and the results revealed that it is more likely for the scintillations to be observed in the west sector of the sky above Shenzhen. During the present period of study, a total number of 512 total electron content (TEC) depletions and 460 lock loss events were observed. In addition, both of these events are likely to increase during periods of high solar activity, especially because the strong scintillations are often simultaneously accompanied by TEC depletions and lock losses by GPS receivers. © 2014 COSPAR. Published by Elsevier Ltd. All rights reserved.
Zhai B.-G.,Changzhou UniversityJiangsu |
Ma Q.-L.,Changzhou UniversityJiangsu |
Ma Q.-L.,Nantong University |
Xiong R.,Wuhan UniversityHubei |
And 2 more authors.
Materials Research Bulletin | Year: 2016
Dy3+ doped barium aluminate (BaAl2O4:Dy3+) phosphors were prepared via the sol-gel combustion route at the ignition temperature of 600 °C. The phosphors were characterized with X-ray diffractometry, scanning electron microscopy, transmission electron microscopy, photoluminescence spectroscopy, Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy. Regardless of the absence of Eu2+ luminescent centers, broadband blue-green afterglow with its peak at about 490 nm was recorded in the BaAl2O4:Dy3+ phosphors. The decay profile of the blue-green afterglow can be best fitted into a two-component exponential function with the two lifetime decay constants to be 8.81 and 45.25 s, respectively. The observation of blue-green afterglow from BaAl2O4:Dy3+ in the absence of Eu2+ provides unique opportunity in unveiling the afterglow mechanisms of rare-earth doped alkaline-metal aluminates. Possible mechanisms on the blue-green afterglow in BaAl2O4:Dy3+ phosphors are discussed in terms of the Dy3+ ions introduced trap centers as well as luminescent centers in the crystal lattice. © 2015 Elsevier Ltd.
Fan C.,Wuhan UniversityHubei |
Wang Y.,Hubei University |
Wang J.,Hubei University |
Lei D.,Wuhan UniversityHubei |
And 6 more authors.
American Journal of Translational Research | Year: 2016
Preeclampsia (PE) is a leading cause of maternal and perinatal morbidity and mortality. Klotho is a novel gene and the secret form, α-klotho (α-KL), is related to preeclampsia. We conducted this cross-sectional study in Wuhan, China. We used immunohistochemistry, real-time PCR, western blot, ELISA to measure α-KL expression in placenta and its secretion in maternal and umbilical cord serum, and analyzed correlations between α-KL level and other parameters in normal and preeclampsia pregnancy. We found that both mRNA and protein expression of placental α-KL in women with PE was significantly lower than that in normal pregnancy. Also, expression level of α-KL in both maternal and umbilical cord was markedly decreased in PE patients. Further analyses showed that serum α-KL exhibited positive association with fetal birth weight, and reverse association with oxidative stress and renal function markers. Receiver operating characteristic analysis suggested α-KL might be a potential predictor for preeclampsia. © 2016, E-Century Publishing Corporation. All rights reserved.
Xing B.,Wuhan UniversityHubei |
Chen H.,Renmin University of China |
Wang L.,Renmin University of China |
Weng X.,Renmin University of China |
And 2 more authors.
Acta Cirurgica Brasileira | Year: 2015
PURPOSE: To investigate the protective effects of ozone oxidative preconditioning (OzoneOP) were associated with the modulation of TLR4-NF-κB pathway. METHODS: Thirty six rats were subjected to 45 min of renal ischemia, with or without treatment with OzoneOP (1 mg/kg). Blood samples were collected for the detection of blood urea nitrogen and creatinine levels. Histologic examinations were evaluated and immunohistochemistry was also performed for localization of TLR4 and NF-κB. The expression of TNF-α, IL-1β, IL-6, ICAM-1 and MCP-1 were studied by Real-time PCR. Western blot was performed to detect the expression of TLR4 and NF-κB. RESULTS: The results indicated that blood urea nitrogen and creatinine levels increased significantly in I/R group. Rats treated with OzoneOP showed obviously less renal damage. Immunohistochemistry showed that TLR4 were ameliorated by OzoneOP. Realtime PCR showed that OzoneOP could significantly inhibit the increased mRNA levels of TNF-α, IL-1β, IL-6, ICAM-1 and MCP-1 induced by I/R. Western blot indicated that the expression of TLR4 and NF-κB were upregulated in I/R group, but OzoneOP could inhibit this increase. CONCLUSION: These findings indicated that OzoneOP had potent anti-inflammatory properties by the modulation of the TLR4-NF-κB pathway in renal ischemia/reperfusion injury. © 2015, Sociedade Brasileira para o Desenvolvimento de Pesquisa em Cirurgia. All rights reserved.
Zou Q.,Wuhan UniversityHubei |
Ni L.,Wuhan UniversityHubei |
Zhang T.,Wuhan UniversityHubei |
Wang Q.,Wuhan UniversityHubei
IEEE Geoscience and Remote Sensing Letters | Year: 2015
With the popular use of high-resolution satellite images, more and more research efforts have been placed on remote sensing scene classification/recognition. In scene classification, effective feature selection can significantly boost the final performance. In this letter, a novel deep-learning-based feature-selection method is proposed, which formulates the feature-selection problem as a feature reconstruction problem. Note that the popular deep-learning technique, i.e., the deep belief network (DBN), achieves feature abstraction by minimizing the reconstruction error over the whole feature set, and features with smaller reconstruction errors would hold more feature intrinsics for image representation. Therefore, the proposed method selects features that are more reconstructible as the discriminative features. Specifically, an iterative algorithm is developed to adapt the DBN to produce the inquired reconstruction weights. In the experiments, 2800 remote sensing scene images of seven categories are collected for performance evaluation. Experimental results demonstrate the effectiveness of the proposed method. © 2004-2012 IEEE.
Zhu J.F.,Wuhan UniversityHubei
Future Information Engineering and Manufacturing Science - Proceedings of the 2014 International Conference on Future Information Engineering and Manufacturing Science, FIEMS 2014 | Year: 2015
The MNEs are inevitably confronted with various discrepancies and even conflicts during their production and operation in China because of the profit-pursuing nature of capital. In order to solve these conflicts, ethics games between the MNEs and Chinese government are proposed in this paper. It can be deduced that there are four main factors accounting for the probability of cooperation, (1) the MNEs’ payoff when strategy set 1 (cooperation & honoring commitment) is adopted; (2) the MNEs’ payoff when strategy set 2 (cooperation & dishonoring commitment) is employed; (3) probability that China has a supervising and administrating government; (4) punishment on the MNEs by Chinese government. To be specific, the higher probability of a law-based government, the stronger punishment on illegal behaviors of the MNEs, and thus more payoff is yielded to the MNEs which choose strategy set 1 (cooperation & honoring commitment), but less to those which adopt strategy set 2 (cooperation & dishonoring commitment). Chinese regulatory government can stimulate the MNEs to honor their commitments that they should shoulder their social responsibility in China and manage their behaviors within the framework of business ethics and codes of ethics. Those findings will provide references for decisionmakers, the government and other departments involved. © 2015 Taylor & Francis Group, London.
Zhang X.,Chongqing University |
Zhang X.,Wuhan UniversityHubei |
Cheng Z.,Chongqing University |
Li X.,Chongqing University
Infrared Physics and Technology | Year: 2016
As one of the key characteristic components that result from sulfur hexafluoride (SF6) decomposition in SF6 gas-insulated equipment, hydrogen sulfide (H2S) can reflect the severity of the internal insulation faults and indicate whether or not such faults involve solid insulation material effectively. The decomposition of SF6 and its reaction with other impurities to form H2S are simulated in this study via Materials Studio. The simulation verifies that H2S is generated only when serious faults occur in the equipment; thus, the online monitoring of the trace H2S is highly necessary. To achieve a high detection accuracy and avoid cross interference, the spectral line R (8) of the H2S ν1 + ν2 + ν3 co-frequency absorption band is taken as the absorption line for the gas detection by online simulation based on the HITRAN on the Web. In addition, this study develops a cantilever-enhanced photoacoustic spectrometry trace gas detection platform and conducts experimental research on the quantitative detection of trace H2S/SF6 and H2S/N2. Experimental results show that the detection sensitivity of the detection platform to trace H2S under the background gas N2 and SF6 is 0.84 and 1.75 μL/L, respectively, and a strong linear relationship exists between the trace H2S concentration and its corresponding PA signal. Moreover, based on both the theoretical simulation and experiment, the influence of temperature and pressure on the detection platform is discussed and analyzed. The results indicate that the change in the PA signal amplitude decreases with an increase in the pressure or temperature of the PA cell, and the detection platform is more sensitive to pressure. © 2016 Elsevier B.V.