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Highly selective separation of vanadium over iron from stone coal by oxalic acid leaching
Pengcheng Hu,Yimin Zhang,Tao Liu,Jing Huang,Yizhong Yuan,Qiushi Zheng 한국공업화학회 2017 Journal of Industrial and Engineering Chemistry Vol.45 No.-
In this paper, a novel method was proposed to selectively extract vanadium from stone coal by oxalicacid leaching. Vanadium was leached, but the iron impurity wasmaintained in the leaching residue. Theeffects of leaching conditions on the leaching efficiency of vanadium and iron were investigated foroxalic and sulfuric acid leaching, respectively. For oxalic acid leaching, 71.5% of the vanadium can berecovered with only 3.4% of the iron impurity leached under the leaching conditions: a dosage of H+ of12 mol/kg, a leaching time of 6 h, a leaching temperature of 368 K (95 8C) and a water–mineral ratio of1.5 L/kg. However, under the same conditions, 74.1% of the vanadium and 13% of the iron were leachedduring sulfuric acid leaching. The XRD and FTIR analyses showed that both oxalic and sulfuric acidleaching can destroy the crystal lattice structure of muscovite, resulting in the leaching efficiency ofvanadium without much difference. Further, the SEM-EDS and XPS analyses indicated that very littlepyrite dissolved during oxalic acid leaching, but that much more pyrite dissolved during sulfuric acidleaching. Therefore, oxalic acid leaching can achieve a highly selective separation of vanadium over ironfrom stone coal.
Motor Current Signal Analysis using a Modified Bispectrum for Machine Fault Diagnosis
Fengshou Gu,Yimin Shao,Niaoqin Hu,Bruno Fazenda,Andrew Ball 제어로봇시스템학회 2009 제어로봇시스템학회 국제학술대회 논문집 Vol.2009 No.8
This paper presents the use of the induction motor current to identify and quantify common faults within a two-stage reciprocating compressor. The theoretical basis is studied to understand current signal characteristics when themotor undertakes a varying load under faulty conditions. Although conventional bispectrum representation of currentsignal allows the inclusion of phase information and the elimination of Gaussian noise, it produces unstable results dueto random phase variation of the sideband components in the current signal. A modified bispectrum based on theamplitude modulation feature of the current signal is thus proposed to combine both lower sidebands and highersidebands simultaneously and hence describe the current signal more accurately. Based on this new bispectrum a more effective diagnostic feature namely normalised bispectral peak is developed for fault classification. In association with the kurtosis of the raw current signal, the bispectrum feature gives rise to reliable fault classification results. Inparticular, the low feature values can differentiate the belt looseness from other fault cases and discharge valve leakage and intercooler leakage can be separated easily using two linear classifiers. This work provides a novel approach to theanalysis of stator current for the diagnosis of motor drive faults from downstream driving equipment.
Three-dimensional Temperature-field Modeling of Large Transformer using Finite Element Method
Qian Suxiang,Hu Hongsheng,Xu Juwu,Shao Yimin 제어로봇시스템학회 2009 제어로봇시스템학회 국제학술대회 논문집 Vol.2009 No.8
Different heat effects will arise due to failures of oil-immersed transformer, thus lead to abnormal temperature rise. Based on the theoretical analysis on temperature-field of transformer, the solid model of large oil immersed transformer was built using SolidWorks, and the temperature-fields are analyzed in this paper. Three-dimensional temperature-fields distribution of transformer are obtained in three typical conditions, which contributes to the state monitor and failure diagnose of transformer.
Xi Fang,Gaofeng Zhan,Jie Zhang,Hui Xu,Bin Zhu,Yimin Hu,Chun Yang,Ailin Luo 대한정신약물학회 2019 CLINICAL PSYCHOPHARMACOLOGY AND NEUROSCIENCE Vol.17 No.2
Objective: Patients with chronic neuropathic pain (CNP) have a higher incidence to develop depression. However, its pathogenesis has not yet been fully elucidated. Here we aimed to investigate the role of inflammatory cytokines in CNP-related anhedonia, which is a core symptom of depression, and to explore the effects of ketamine and parecoxib on pain and anhedonia. Methods: A rat model of spared nerve injury (SNI) was constructed to mimic CNP. Hierarchical cluster analysis of sucrose preference test (SPT) was applied to classify the SNI rats into anhedonia susceptible and unsusceptible. Inflammatory cytokines in medial prefrontal cortex (mPFC) of brain, serum and L2-5 spinal cord were measured. Moreover, effects of ketamine or parecoxib on mechanical withdrawal test (MWT) and SPT in anhedonia susceptible rats were detected. Results: Tumor necrosis factor (TNF)- was increased in mPFC, serum and and spinal cord of anhedonia susceptible rats. Furthermore, anhedonia susceptible and unsusceptible rats both increased the interleukin (IL)-1 level in mPFC, serum and spinal cord. IL-6 was altered in serum and spinal cord, but not in mPFC. IL-10 was significantly altered in mPFC and serum, but not in spinal cord. Additionally, ketamine treatment significantly attenuated the decreased results of MWT and SPT in anhedonia susceptible rats, and that parecoxib significantly improved the MWT score, but failed to alter the result of SPT. Conclusion: These findings suggest that abnormalities in inflammatory cytokines confer susceptible to anhedonia in a rat model of SNI. Ketamine, a fast-acting antidepressant, has pharmacological benefits to alleviate pain and anhedonia symptoms.
Yixiang Ai,Dereje Gobena Alemayehu,Genwen Mao,Yaping Liang,Ran Cao,Jiale Hu,Yimin Yang,Zhiwei Ren 대한정형외과학회 2023 Clinics in Orthopedic Surgery Vol.15 No.6
Background: To evaluate the feasibility of treating odontoid fractures in the Chinese population with two cortical screws based on computed tomography (CT) scans and describe a new measurement strategy to guide screw insertion in treating these fractures. Methods: A retrospective review of cervical computed tomographic scans of 128 patients (aged 18–76 years; men, 55 [43.0%]) was performed. The minimum external transverse diameter (METD), minimum external anteroposterior diameter (MEAD), maximum screw length (MSL), and screw projection back angle (SPBA) of the odontoid process were measured on coronal and sagittal CT images. Results: The mean values of METD and MEAD were 10.0 ± 1.1 mm and 12.0 ± 1.0 mm, respectively, in men and 9.2 ± 1.0 mm and 11.0 ± 1.0 mm, respectively, in women. Both measurements were significantly higher in men (p < 0.001). In total, 87 individuals (68%) had METD > 9.0 mm that could accommodate two 3.5-mm cortical screws. The mean MSL value and SPBA range were 34.4 ± 2.9 mm and 13.5°–24.2°, respectively, with no statistically significant difference between men and women. Conclusions: The insertion of two 3.5-mm cortical screws was possible for anterior fixation of odontoid fractures in 87 patients (68%) in our study, and there was a statistically significant difference between men and women.