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| 1 | Early Detection of Lesions of Dorsal Artery of Foot in Patients with Type 2 Diabetes Mellitus by High-frequency Ultrasonography显示文摘This study evaluated the value of high-frequency ultrasonograpy for early detection of dorsal artery of foot in patients with type 2 diabetes mellitus (MD). Eighty subjects including 40 patients with type 2 MD (T2DM group) and 40 healthy volunteers (NC group) were recruited. The in-tima-media thickness (IMT), the inner diameter and the perfusion of dorsal artery of foot were meas-ured by using high-frequency ultrasonograpy. Meanwhile, the parameters of vascular elasticity, including stiffness parameter (β), pressure-strain elastic modulus (Eρ), arterial compliance (AC), aug-ment index (AI), and pulse wave conducting velocity (PWVβ) were detected by means of echo-tracking technique. The results showed that no significant difference was found in the IMT, systolic diameter (Ds), diastolic diameter (Dd) and peak systolic velocity (PSV) between T2DM and NC groups. Eρ and PWVβ were increased, and AC was decreased in T2DM group as compared with those in NC group with the differences being significant (P<0.05 for all). There was no significant difference in β and AI between T2DM and NC groups. It was concluded that high-frequency ultra-sonography in combination with echo-tracking technique is sensitive and non-invasive, and can be used for early detection of sclerosis of the lower extremity artery in patients with type 2 MD. | 张艳容 李雯静 严天慰 鲁成发 周翔 黄艳 | 2009 | Journal of Huazhong University of Science and Technology(Medical Sciences)2009，29，3： | 149 |
| 2 | Fracture evolution and pressure relief gas drainage from distant protected coal seams under an extremely thick key stratum显示文摘When an extremely thick rock bed exists above a protected coal seam in the bending zone given the condition of a min- ing protective seam, this extremely thick rock bed controls the movement of the entire overlying stratum. This extremely thick rock bed, called a 'main key stratum', will not subside nor break for a long time, causing lower fractures and bed separations not to close and gas can migrate to the bed separation areas along the fractures. These bed separations become gas enrichment areas. By analyzing the rule of fracture evolution and gas migration under the main key stratum after the deep protective coal seam has been mined, we propose a new gas drainage method which uses bore holes, drilled through rock and coal seams at great depths for draining pressure relief gas. In this method, the bores are located at a high level suction roadway (we can also drill them in the drill- ing field located high in an air gateway). Given the practice in the Haizi mine, the gas drainage rate can reach 73% in the middle coal group, with a gas drainage radius over 100m. | WANG Liang CHENG Yuan-ping LI Feng-rong WANG Hai-feng LIU Hai-bo | 2008 | Journal of China University of Mining and Technology2008，18，2： | 53 |
| 3 | Deposit 3D modeling and application显示文摘By the aid of the international mining software SURPAC, a geologic database for a multi-metal mine was established, 3D models of the surface, geologic fault, ore body, cavity and the underground openings were built, and the volume of the cavity of the mine based on the cavity 3D model was calculated. In order to compute the reserves, a grade block model was built and each metal element grade was estimated using Ordinary Kriging. Then, the reserve of each metal element and every sublevel of the mine was worked out. Finally, the calculated result of each metal reserve to its actual prospecting reserve was compared, and the results show that they are all almost equal to each other. The absolute errors of Sn, Pb, and Zn reserves are only 1.45%, 1.59% and 1.62%, respectively. Obviously, the built models are reliable and the calculated results of reserves are correct. They can be used to assist the geologic and mining engineers of the mine to do research work of reserves estimation, mining design, plan making and so on. | 罗周全 刘晓明 苏家红 吴亚斌 刘望平 | 2007 | Journal of Central South University of Technology2007，14，2： | 45 |
| 4 | Improved BP Neural Network for Transformer Fault Diagnosis显示文摘The back propagation (BP)-based artificial neural nets (ANN) can identify complicated relationships among dissolved gas contents in transformer oil and corresponding fault types, using the highly nonlinear mapping nature of the neural nets. An efficient BP-ALM (BP with Adaptive Learning Rate and Momentum coefficient) algorithm is proposed to reduce the training time and avoid being trapped into local minima, where the learning rate and the momentum coefficient are altered at iterations. We developed a system of transformer fault diagnosis based on Dissolved Gases Analysis (DGA) with a BP-ALM algorithm. Training patterns were selected from the results of a Refined Three-Ratio method (RTR). Test results show that the system has a better ability of quick learning and global convergence than other methods and a superior performance in fault diagnosis compared to convectional BP-based neural networks and RTR. | SUN Yan-jing ZHANG Shen MIAO Chang-xin LI Jing-meng | 2007 | Journal of China University of Mining and Technology2007，17，1： | 39 |
| 5 | Groundwater Pollution from Underground Coal Gasification显示文摘In situ coal gasification poses a potential environmental risk to groundwater pollution although it depends mainly on local hydrogeological conditions. In our investigation,the possible processes of groundwater pollution origi-nating from underground coal gasification (UCG) were analyzed. Typical pollutants were identified and pollution con-trol measures are proposed. Groundwater pollution is caused by the diffusion and penetration of contaminants generated by underground gasification processes towards surrounding strata and the possible leaching of underground residue by natural groundwater flow after gasification. Typical organic pollutants include phenols,benzene,minor components such as PAHs and heterocyclics. Inorganic pollutants involve cations and anions. The natural groundwater flow after gasification through the seam is attributable to the migration of contaminants,which can be predicted by mathematical modeling. The extent and concentration of the groundwater pollution plume depend primarily on groundwater flow ve-locity,the degree of dispersion and the adsorption and reactions of the various contaminants. The adsorption function of coal and surrounding strata make a big contribution to the decrease of the contaminants over time and with the distance from the burn cavity. Possible pollution control measures regarding UCG include identifying a permanently,unsuitable zone,setting a hydraulic barrier and pumping contaminated water out for surface disposal. Mitigation measures during gasification processes and groundwater remediation after gasification are also proposed. | LIU Shu-qin LI Jing-gang MEI Mei DONG Dong-lin | 2007 | Journal of China University of Mining and Technology2007，17，4： | 36 |
| 6 | Location of high seismic activity zones and seismic hazard assessment in Zabrze Bielszowice coal mine using passive tomography显示文摘In the paper results of passive tomography calculations have been presented to assess rockburst hazard and locate high seismic activity zones in the vicinity of longwall 306 in Zabrze Bielszowice coal mine. The area of study was 1000 m in X direction by 900 m in Y direction. The zones of high values of P-wave propagation velocity have been found to correlate with the distribution of large seismic tremors. | LURKA A | 2008 | Journal of China University of Mining and Technology2008，18，2： | 35 |
| 7 | Misdiagnosis and Delayed Diagnosis for Ectopic and Heterotopic Pregnancies after In Vitro Fertilization and Embryo Transfer显示文摘This study examined the misdiagnosis and delayed diagnosis factors for ectopic pregnancy(EP)and heterotopic pregnancy(HP)after in vitro fertilization and embryo transfer(IVF-ET)in an attempt to reduce the diagnostic error.Clinical data of patients who underwent IVF-ET treatment and had clinical pregnancy from 12463 cycles were retrospectively analyzed.Their findings of serumβ-hCG test and transvaginal ultrasonography were also obtained during follow-up.These patients were divided into two groups according to the diagnosis accuracy of EP/HP:early diagnosis and misdiagnosis/delayed diagnosis.The results showed that the incidence of EP and HP was 3.8%(125/3286)and 0.8%(27/3286)respectively for IVF/ICSI-ET cycle,and 3.8%(55/1431)and 0.7%(10/1431)respectively for frozen-thawed embryo transfer(FET)cycle.Ruptured EP occurred in 28 patients due to initial misdiagnosis or delayed diagnosis.Related factors fell in 3 categories:(1)clinician factors:misunderstanding of patients’medical history,insufficient training in ultrasonography and unawareness of EP and HP;(2)patient factors:noncompliance with medical orders and lack of communication with clinicians;(3)complicated conditions of EP:atypical symptoms,delayed elevation of serumβ-hCG level,early rupture of cornual EP,asymptomatic in early gestation and pregnancy of unknown location.All the factors were interwoven,contributing to the occurrence of EP and HP.It was concluded that complicated conditions are more likely to affect the diagnosis accuracy of EP/HP after IVF-ET.Transvaginal ultrasonography should be performed at 5 weeks of gestation.Intensive follow-up including repeated ultrasonography and serial serumβ-hCG tests should be performed in patients with a suspicious diagnosis at admission. | 王琳琳 陈薪 叶德盛 刘玉东 何于夏 郭薇 陈士岭 | 2014 | Journal of Huazhong University of Science and Technology(Medical Sciences)2014，34，1： | 37 |
| 8 | A Comparative Study of High-viscosity Cement Percutaneous Vertebroplasty vs. Low-viscosity Cement Percutaneous Kyphoplasty for Treatment of Osteoporotic Vertebral Compression Fractures显示文摘The clinical effects of two different methods–high-viscosity cement percutaneous vertebroplasty(PVP) and low-viscosity cement percutaneous kyphoplasty(PKP) in the treatment of osteoporotic vertebral compression fractures(OVCFs) were investigated. From June 2010 to August 2013, 98 cases of OVCFs were included in our study. Forty-six patients underwent high-viscosity PVP and 52 patients underwent low-viscosity PKP. The occurrence of cement leakage was observed. Pain relief and functional activity were evaluated using the Visual Analog Scale(VAS) and Oswestry Disability Index(ODI), respectively. Restoration of the vertebral body height and angle of kyphosis were assessed by comparing preoperative and postoperative measurements of the anterior heights, middle heights and the kyphotic angle of the fractured vertebra. Nine out of the 54 vertebra bodies and 11 out of the 60 vertebra bodies were observed to have cement leakage in the high-viscosity PVP and low-viscosity PKP groups, respectively. The rate of cement leakage, correction of anterior vertebral height and kyphotic angles showed no significant differences between the two groups(P>0.05). Low-viscosity PKP had significant advantage in terms of the restoration of middle vertebral height as compared with the high-viscosity PVP(P<0.05). Both groups showed significant improvements in pain relief and functional capacity status after surgery(P<0.05). It was concluded that high-viscosity PVP and low-viscosity PKP have similar clinical effects in terms of the rate of cement leakage, restoration of the anterior vertebral body height, changes of kyphotic angles, functional activity, and pain relief. Low-viscosity PKP is better than high-viscosity PVP in restoring the height of the middle vertebra. | 孙凯 刘洋 彭昊 谭俊峰 张觅 郑先念 陈方舟 李明辉 | 2016 | Journal of Huazhong University of Science and Technology(Medical Sciences)2016，36，3： | 35 |
| 9 | Role of Heart-Type Fatty Acid Binding Protein in Early Detection of Acute Myocardial Infarction in Comparison with cTnI, CK-MB and Myoglobin显示文摘Heart fatty acid-binding protein (H-FABP) is supposed to be the most sensitive biomarker of early acute myocardial infarction (AMI). To evaluate the diagnostic value of H-FABP for AMI in the early stage, the plasma levels of H-FABP were measured by sandwich ELISA in 93 patients with suspected AMI at admission within 6 h after onset of chest pain and 69 normal healthy subjects. The plasma concentrations of cardiac troponin-I (cTnI), creatine kinase-MB (CK-MB) and myoglobin (Mb) were assayed at the same time by using corpuscle chemiluminescence for those patients. The patients were classified as AMI group (n=32) and non-AMI group (n=61) retrospectively. The diagnostic validity was evaluated in terms of sensitivity, specificity and receiver operating characteristic (ROC) curve analysis. The results showed the cutoff value of H-FABP for AMI was 16.8 ng/ml, and its diagnostic sensitivity for AMI was 64.29 % within 3 h and 84.38 % within 6 h after onset of chest pain, and the diagnostic specificity for non-AMI was 100 % within 3 h and 91.8 % within 6 h. H-FABP had higher sensitivity than that of cTnI and CK-MB at all time points (P<0.05), whereas there was no significant difference in specificity among the four markers. But the area under the ROC curve of H-FABP was significantly greater than that of cTnI, CK-MB and Mb within 3 h. These results revealed that H-FABP possessed high diagnostic sensitivity and specificity for AMI in early stage, especially within 3 h after onset of persistent angina pectoris. In conclusion, H-FABP can be used as a sensitive marker for AMI in the early stage. | 陈莉莉 郭小梅 杨霏 | 2004 | Journal of Huazhong University of Science and Technology(Medical Sciences)2004，24，5： | 33 |
| 10 | Effects of low temperature on properties of structural steels显示文摘The experiments were carried out to measure the mechanical properties of three grades of structural steels (Q235A, 16Mn and Q390E steel ) at low temperature. It was shown that the strength of the steels increases while the plasticity and toughness decrease as temperature drops. In the transitional area the toughness drops rapidly with temperature. Among the three structural steels,Q390E steel has the best toughness and the lowest sensitivity. | YanminWu YuanqingWang YongjiuShi JianjingJiang | 2004 | Journal of University of Science and Technology Beijing2004，11，5： | 29 |
| 11 | Effects of Metallic Ions on the Flotation of Spodumene and Beryl显示文摘Effects of multivalent metallic cations, such as Ca2+ and Fe3+, on the flotation of spodumene and beryl were studied. The results show that Fe3+ and Ca2+ exhibit efficient activation on the flotation of spodumene and beryl. The ac- tivation of Fe3+ happens quite well within a pH range of 6-9 while the concentration of Fe3+ is 35 mg/L. Efficient acti- vation of Ca2+ takes place over at a pH over 11.6 at a concentration of 140 mg/L. The zeta potential of beryl and spo- dumene shifts slightly to positive values when activated by Ca2+, but markedly by Fe3+. New stretching frequencies of 1594.24 cm-1 and 1587.13 cm-1 have been found in the FTIR spectra of the two minerals after their interaction with Fe3+ and the collector. These new stretching frequencies are the asymmetric stretching frequencies of COO-(carboxyl anion), so thecollector may be chemically absorbed on the surface of Fe3+-activated beryl and spodumene. | WANG Yu-hua YU Fu-shun | 2007 | Journal of China University of Mining and Technology2007，17，1： | 29 |
| 12 | Gas seepage equation of deep mined coal seams and its application显示文摘In order to obtain a gas seepage law of deep mined coal seams, according to the properties of coalbed methane seepage in in-situ stress and geothermal temperature fields, the gas seepage equation of deep mined coal seams with the Klinkenberg effect was obtained by confirming the coalbed methane permeability in in-situ stress and geothermal temperature fields. Aimed at the condition in which the coal seams have or do not have an outcrop and outlet on the ground, the application of the gas seepage equa- tion of deep mined coal seams in in-situ stress and geothermal temperature fields on the gas pressure calculation of deep mined coal seams was investigated. The comparison between calculated and measured results indicates that the calculation method of gas pressure, based on the gas seepage equation of deep mined coal seams in in-situ stress and geothermal temperature fields can accu- rately be identical with the measured values and theoretically perfect the calculation method of gas pressure of deep mined coal seams. | HU Guo-zhong WANG Hong-tu TAN Hai-xiang FAN Xiao-gang YUAN Zhi-gang | 2008 | Journal of China University of Mining and Technology2008，18，4： | 29 |
| 13 | Incidence and Risk Factors of Cognitive Impairment 3 Months after First-ever Stroke: A Cross-sectional Study of 5 Geographic Areas of China显示文摘This study examined the incidence, neuropsychological characteristics and risk factors of cognitive impairment 3 months after stroke in China. Five regions that differed in geography and economy in China were selected. Patients from the hospitals located in the five regions were prescreened at admission, and the demographic data, vascular risk factors and clinical characteristics of stroke were obtained. A battery of cognitive-specific domain tests was performed in the patients who failed to pass cognitive screening 3 months post stroke. Patients were diagnosed as having post-stroke cognitive impairment (PSCI) or no cognitive impairment (NCI) based on the results of the neuropsy-chological tests. Univariate analysis was performed for suspect risk factors, and significant variables were entered in multivariable logistic regression analysis. Our results showed that a total of 633 patients were recruited 3 months after stroke; complete cognitive tests were performed in 577 of the stroke pa-tients. The incidence of PSCI in these Chinese patients was 30.7%. There were 129 (22.4%) patients with visuospatial impairment, 67 (11.6%) with executive impairment, 60 (10.4%) with memory impairment and 18 (3.1%) with attention impairment. The risk factors associated with PSCI were older age (odds ratio [OR] 1.76, 95% confidence interval [CI] 1.20-2.58), low education level (OR 2.45, 95% CI 1.65-3.64), depressive symptom (OR 1.69, 95% CI 1.09-2.61), obesity (OR 2.57, 95% CI 1.41-4.71), stroke severity 3 months post stroke (OR 1.62, 95%CI 1.10-2.37) and cortex lesion (OR 1.55, 95% CI 1.04-2.31). It was concluded that PSCI occurs commonly 3 months after first-ever stroke in Chinese patients. Visuospatial ability may be the most frequently impaired cognitive domain for the patients with stroke. The critical risk factors of PSCI are older age, low education level, depressive symptom, obesity, stroke severity 3 months post stroke and cortex lesion. | 张勇 张振馨 杨百渔 李延峰 张蕲 屈秋民 王延平 张世红 岳卫东 谭毓绘 张宝荣 徐涛 | 2012 | Journal of Huazhong University of Science and Technology(Medical Sciences)2012，32，6： | 29 |
| 14 | Dexmedetomidine Alleviates Pulmonary Edema by Upregulating AQP1 and AQP5 Expression in Rats with Acute Lung Injury Induced by Lipopolysaccharide显示文摘This study aims to elucidate the mechanisms by which dexmedetomidine alleviates pulmonary edema in rats with acute lung injury induced by lipopolysaccharide(LPS). Male Wistar rats were randomly divided into five groups: normal saline control(NS) group,receiving intravenous 0.9% normal saline(5 m L/kg); LPS group,receiving intravenous LPS(10 mg/kg); small-dose dexmedetomidine(S) group,treated with a small dose of dexmedetomidine(0.5 μg·kg-1·h-1); medium-dose dexmedetomidine(M) group,treated with a medium dose of dexmedetomidine(2.5 μg·kg-1·h-1); high-dose dexmedetomidine(H) group,treated with a high dose of dexmedetomidine(5 μg·kg-1·h-1). The rats were sacrificed 6 h after intravenous injection of LPS or NS,and the lungs were removed for evaluating histological characteristics and determining the lung wet/dry weight ratio(W/D). The levels of tumor necrosis factor-alpha(TNF-α) and interleukin-1β(IL-1β) in the lung tissues were assessed by enzyme-linked immunosorbent assay(ELISA). The m RNA and protein expression levels of aquaporin-1(AQP1) and aquaporin-5(AQP5) were detected by RT-PCR,immunohistochemistry,and Western blotting. The lung tissues from the LPS groups were significantly damaged,which were less pronounced in the H group but not in the small-dose dexmedetomidine group or medium-dose dexmedetomidine group. The W/D and the concentrations of TNF-α and IL-1β in the pulmonary tissues were increased in the LPS group as compared with those in NS group,which were reduced in the H group but not in S group or M group(P<0.01). The expression of AQP1 and AQP5 was lower in the LPS group than in the NS group,and significantly increased in the H group but not in the S group or M group(P<0.01). Our findings suggest that dexmedetomidine may alleviate pulmonary edema by increasing the expression of AQP-1 and AQP-5. | 姜远旭 戴中亮 张雪萍 赵伟 黄强 高利昆 | 2015 | Journal of Huazhong University of Science and Technology(Medical Sciences)2015，35，5： | 30 |
| 15 | Expression of Survivin, CyclinD1, p21^(WAF1), Caspase-3 in Cervical Cancer and Its Relation with Prognosis显示文摘The implications of Survivin, CyclinD1, p21 WAF1, Caspase-3 in the development, progression and prognosis in cervical cancer were investigated. By using immunohistochemical SP method, the expression of Survivin, CyclinD1, p21 WAF1, Caspase-3 was detected in 41 cases of cervical cancer, 17 cases of cervical intraepithelial neoplasia (CIN) and 10 cases of normal tissues, and their relation with pathological grade, clinical stage, metastasis and survival time was analyzed. The results showed that the positive expression rate of Survivin, CyclinD1 in cervical cancer was significantly higher than in CIN group and normal control group (P<0.05). The median survival time in the patients with cervical cancer positive for Survivin and CyclinD1 was significantly shorter than in those with negative expression (P<0.05). The expression of both Survivin and CyclinD1 was not related with tumor grade, clinical stage and metastasis (P>0.05). The positive expression rate of p21 WAF1, Caspase-3 in cervical cancer was significantly lower than in CIN group and normal control group (P<0.05), and had a close relation with tumor grade (P<0.05). The expression of Survivin in cervical cancer in cervical cancer was negatively associated with that of Caspase-3 (P<0.01), but positively with that of CyclinD1 (P<0.01). Cox Multivariate analysis revealed that Survivin was the independent prognostic indicator influencing the survival time of the patients with cervical cancer (P<0.05). It was suggested that the high expression of Survivin or CyclinD1, and low expression of p21 WAF1 or Caspase-3 was closely correlated with the development of cervical cancer. Survivin and CyclinD1 could be used as a useful indicator to predict the prognosis of cervical cancer. | 卢实 张保华 王泽华 | 2005 | Journal of Huazhong University of Science and Technology(Medical Sciences)2005，25，1： | 28 |
| 16 | Numerical Simulation of Rock Burst in Circular Tunnels Under Unloading Conditions显示文摘Rock burst in a circular tunnel under high in-situ stress conditions was investigated with a numerical method coupled the rock failure process theory (RFPA) and discontinuous deformation theory (DDA). Some numerical tests were carraied out to investigate the failuer patterns of circular tunnel under unloading conditions. Compared the results under loading conditions,the shapes of failure zones are more regular under the unloading conditions. The failure pat-terns in the same type of rock mass are clearly different because of non-homogeneity of the rock material. The extension of cracks shows some predictability with an increasing of in-situ stress. When the homogeneity index of rocks (m) is ei-ther relatively high or low and lateral pressure coefficients (λ) is high,the number of regular shear slide cracks decreases and the probability of a rock burst also becomes lower. Our numerical simulation results show that the stability of sur-face rock and the natural bedding stratification of rock material greatly affect rock bursts. Installing bolts with due dili-gence and suitably can effectively prevent rock bursts. However,it is not effective to control rock bursts by releasing the strain energy with normal pre-boreholes. | SUN Jin-shan ZHU Qi-hu LU Wen-bo | 2007 | Journal of China University of Mining and Technology2007，17，4： | 28 |
| 17 | A forecasting and forewarning model for methane hazard in working face of coal mine based on LS-SVM显示文摘To improve the precision and reliability in predicting methane hazard in working face of coal mine, we have proposed a forecasting and forewarning model for methane hazard based on the least square support vector (LS-SVM) multi-classifier and regression machine. For the forecasting model, the methane concentration can be considered as a nonlinear time series and the time series analysis method is adopted to predict the change in methane concentration using LS-SVM regression. For the forewarning model, which is based on the forecasting results, by the multi-classification method of LS-SVM, the methane hazard was identified to four grades: normal, attention, warning and danger. According to the forewarning results, corresponding measures are taken. The model was used to forecast and forewarn the K9 working face. The results obtained by LS-SVM regression show that the forecast- ing have a high precision and forewarning results based on a LS-SVM multi-classifier are credible. Therefore, it is an effective model building method for continuous prediction of methane concentration and hazard forewarning in working face. | CAO Shu-gang LIU Yan-bao WANG Yan-ping | 2008 | Journal of China University of Mining and Technology2008，18，2： | 27 |
| 18 | Waste-filling in fully-mechanized coal mining and its application显示文摘A fully-mechanized coal mining (FMCM) technology capable of filling up the goaf with wastes (including solid wastes) is described. Industrial tests have proved that by using this technology not only can waste be re-used but also coal resources can be exploited with a higher recovery rate without removing buildings located over the working faces. Two special devices, a hydraulic support and a scraper conveyor, run side-by-side on the same working face to simultaneously realize mining and filling. These are described in detail. The tests allow analysis of rock pressure and ground subsidence when backfilling techniques are employed. These values are compared to those from mining without using backfilling techniques, under the same geological conditions. The concept of equivalent mining height is proposed based on theoretical analysis of rock pressure and ground subsidence. The upper limits of the rock pressure and ground subsidence can be estimated in backfilling mining using this concept along with traditional engineering formulae. | MIAO Xie-xing ZHANG Ji-xiong FENG Mei-mei | 2008 | Journal of China University of Mining and Technology2008，18，4： | 27 |
| 19 | Simulation of spatially coupling dynamic response of train-track time-variant system显示文摘There exist three problems in the calculation of lateral vibration of the train-track time-variant system athome and abroad and the method to solve them is presented. Spatially coupling vibration analysis model of train-track time-variant system is put forward. Each vehicle is modeled as a multi-body system with 26 degrees of freedomand the action of coupler is also considered. The track structure is modeled as an assembly of track elements with 30degrees of freedom, then the spatially coupling vibration matrix equation of the train-track time-variant system is es-tablished on the basis of the principle of total potential energy with stationary value and the 'set-in-right-position'rule. The track vertical geometric irregularity is considered as the excitation source of the vertical vibration of thesystem, and the hunting wave of car bogie frame is taken as the excitation source of lateral vibration of the system.The spatially coupling vibration matrix equation of the system is solved by Wilson-θ direct integration method. Theapproximation of the calculated results to the spot test results demonstrates the feasibility and effectiveness of thepresented analysis method. Finally, some other vibration responses of the system are also obtained. | 向俊 李德建 曾庆元 | 2003 | Journal of Central South University of Technology2003，10，3： | 26 |
| 20 | Stability of Ultra-fine Microstructures during Tempering显示文摘The stability of ultra-fine microstructure during tempering at 650℃ was investigated on a Nb-containing steel. The steel had undergone 5 passes controlled rolling, then was relaxed (air cooled) to 730 ℃ and cooled in water The evolution of microstructure was that, in early stage of tempering, no obvious change was detected by means of optical microscopy while dislocation cells were formed inside bainitic laths. With further tempering, bainitic laths started to coalesce in some regions. Finally, polygonal ferrite was formed while hardness decreased dramatically. Some samples taken from the same primary plate were reheated at 930 ℃for 0.5 h followed by quenching into water before tempering. Despite their lower original hardness, the reheated samples softened faster during tempering. Ferrite was quickly formed in the reheated samples. These results indicate that the evolution of microstructures towards equilibrium during tempering of the steel is mainly determined by whether dislocations are pinned rather than the dislocation density. | Shanwu Yang, Chengjia Shang,Xinlai He, Xuemin Wang, Yi Yuan (Material Science and Engineering School, University of Science and Technology Beijing, Beijing 100083, China) | 2001 | Journal of University of Science and Technology Beijing2001，8，2： | 25 |
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