The initiation and evolution of short-pitch corrugation in Beijing metro line 4 was studied from the viewpoint of wheelset vibration.A three-dimensional elastic model was set up.Numerical simulations were undertaken w...The initiation and evolution of short-pitch corrugation in Beijing metro line 4 was studied from the viewpoint of wheelset vibration.A three-dimensional elastic model was set up.Numerical simulations were undertaken with this model to analyze the corrugation by the wheelset vertical vibration and torsional vibration.Based on numerical results,the relation between rail corrugation and wheelset vibration,and the relation between the position of electromotor and wheelset vibration were indicated.It is found that avoiding the wheelset-rail resonance is one method of controlling the rail short-pitch corrugation and solving the vibration and noise problem in metro lines.展开更多
This work was aimed to study the relative floatability of phosphate flotation by means of kinetic analysis.The relative floatability is important to determine how selectively the phosphate is separated from its impuri...This work was aimed to study the relative floatability of phosphate flotation by means of kinetic analysis.The relative floatability is important to determine how selectively the phosphate is separated from its impurities. The effects of pulp pH, solid content, reagents dosage(depressant, collector and co-collector) and conditioning time were investigated on the ratio of the modified rate constant of phosphate to the modified rate constant of iron(relative floatability). The results showed that a large dosage of depressant associated with a low value of collector resulted in a better relative floatability. Increasing the co-collector dosage, conditioning time and pH increased the relative floatability up to a certain value and thereafter resulted in diminishing the relative floatability. Meanwhile, the results indicated that increment of solid concentration increased the relative floatability in range investigated. It was also found that that maximum relative floatability(16.05) could be obtained in pulp pH, 9.32, solid percentage, 30,depressant dosage, 440 g/t, collector dosage, 560 g/t, co-collector dosage, 84.63 g/t and conditioning time,9.43 min.展开更多
Based on the annual production data collected by the Statistic Center of the Ministry of Railways of the People＇s Republic of China, we calculated the energy saving and direct emission reductions of CO2, soot, SO2, C...Based on the annual production data collected by the Statistic Center of the Ministry of Railways of the People＇s Republic of China, we calculated the energy saving and direct emission reductions of CO2, soot, SO2, CO, NOx and CnHm of electrified railways, and analyzed their dynamic characteristics during the period of 1975 2007. The results show that during this period, the annual mean values of energy saving is 1.23×10^6 tce, and direct emission reduction of CO2, soot, SO2, CO, NOx and CnHm are 4.267×10^6 t, 20.5×10^3 t, 3.0×10^3 t, 9.6×10^3 t, 67.9×10^3 t, and 6.9×10^3 t per year, respectively. The annual average increasing rates of energy saving is 139×10^3 tce, and direct emission reduction of CO2, soot, SO2, CO, NOx and CnHm are 483×10^3 t, 2.3×10^3 t, 0.34×10^3 t, 1.1×10^3 t, 7.7 ×10^3 t and 0.78×10^3 t per year, respectively. The electrified railways have played an important role in decreasing the energy consumption and air pollutant emissions of China＇s railway system. The results of this study could provide some reference knowledge for future reductions of energy consumption and waste gas emission in China＇s railway transportation.展开更多
The article summarizes related research results and achievements of elastomer expansion device in railway bridge and puts forward a new idea of using polyurethane elastomer material to seal concrete bridge joints betw...The article summarizes related research results and achievements of elastomer expansion device in railway bridge and puts forward a new idea of using polyurethane elastomer material to seal concrete bridge joints between adjacent spans in heavy haul railways. The new type expansion device is composed of polyurethane elastomer material and named TTXF （elastomer expansion joint）. In theory, researchers find out expansion joint deformation regularity between adjacent bridge spans through theoretical analysis and detection in heavy haul railways, such as Datong-Qinhuangdao Railway and Shenchi-Huanghua Port Railway. Fatigue tests prove that TTXF can adapt to permanent and dynamic deformation. On the other hand, it has been successfully applied in the test section of Central South of Shanxi Railway Passage and continuous monitoring has been conducted in extreme weather for over one year. The expansion joint has a good effect practically.展开更多
Despite heavy consumption over a long period of time, only a small number of alcoholics develop alcoholic liver disease. This alludes to the possibility that other factors, besides alcohol, may be involved in the prog...Despite heavy consumption over a long period of time, only a small number of alcoholics develop alcoholic liver disease. This alludes to the possibility that other factors, besides alcohol, may be involved in the progression of the disease. Over the years, many such factors have indeed been identified, including iron. Despite being crucial for various important biological processes, iron can also be harmful due to its ability to catalyze Fenton chemistry. Alcohol and iron have been shown to interact synergistically to cause liver injury. Iron-mediated cell signaling has been reported to be involved in the pathogenesis of experimental alcoholic liver disease. Hepcidin is an iron-regulatory hormone synthesized by the liver, which plays a pivotal role in iron homeostasis. Both acute and chronic alcohol exposure suppress hepcidin expression in the liver. The sera of patients with alcoholic liver disease, particularly those exhibiting higher serum iron indices, have also been reported to display reduced prohepcidin levels. Alcohol-mediated oxidative stress is involved in the inhibition of hepcidin promoter activity and transcription in the liver. This in turn leads to an increase in intestinal iron transport and liver iron storage. Hepcidin is expressed primarily in hepatocytes. It is noteworthy that both hepatocytes and Kupffer cells are involved in the progression of alcoholic liver disease. However, the activation of Kupffer cells and TNF-α signaling has been reported not to be involved in the down-regulation of hepcidin expression by alcohol in the liver. Alcohol acts within the parenchymal cells of the liver to suppress the synthesis of hepcidin. Due to its crucial role in the regulation of body iron stores, hepcidin may act as a secondary risk factor in the progression of alcoholic liver disease. The clarification of the mechanisms by which alcohol disrupts iron homeostasis will allow for further understanding of the pathogenesis of alcoholic liver disease.展开更多
The study was performed to determine whether the srum concentrations of IL （interleukin）-6 are elevated in patients with RA （rheumatoid arthritis） and to investigate the relationship between IL-6 levels and iron s...The study was performed to determine whether the srum concentrations of IL （interleukin）-6 are elevated in patients with RA （rheumatoid arthritis） and to investigate the relationship between IL-6 levels and iron status in RA patients. 95 serum samples were obtained, 70 of them from patients with RA who had visited the department of Rheumatology at Al-Sadder medical city in Najaf governorate （Iraq） and 25 age and sex-matched healthy controls. The authors assessed the clinical parameters of the disease, including ESR （erythrocyte sedimentation rate）, CRP （C-reactive protein）, and RF （rheumatoid factor）. Serum levels of iron and TIBC （total iron binding capacity） were measured spectrophotometrically, while TS% （transferrin saturation percentage） and transferrin concentration were calculated mathematically. Serum concentrations of IL-6 （interleukin-6） and ferritin were measured using an ELISA （enzyme-linked immunosorbent assay）. The results of serum concentration of IL-6 （interleukin-6） and ferritin were significantly elevated （P 〈 0.0001） in patients with RA compared to those of healthy controls. On the other hand, serum concentrations of iron, TIBC （total iron binding capacity）, TS% （transferrin saturation percentage） and transferrin concentration were significantly decreased in patients with RA compared with those of healthy controls. These findings suggest that anemia is the most frequent observations in patients with RA and mostly associative with increasing level of interleukin-6.展开更多
基金Project(C11H00021) supported by Beijing Municipal Science & Technology Commission of ChinaProject(KCJB11063536) supported by Beijing Jiaotong University,China
文摘The initiation and evolution of short-pitch corrugation in Beijing metro line 4 was studied from the viewpoint of wheelset vibration.A three-dimensional elastic model was set up.Numerical simulations were undertaken with this model to analyze the corrugation by the wheelset vertical vibration and torsional vibration.Based on numerical results,the relation between rail corrugation and wheelset vibration,and the relation between the position of electromotor and wheelset vibration were indicated.It is found that avoiding the wheelset-rail resonance is one method of controlling the rail short-pitch corrugation and solving the vibration and noise problem in metro lines.
基金the phosphate Esfordi MineShahrood University of Technology for their support during this research
文摘This work was aimed to study the relative floatability of phosphate flotation by means of kinetic analysis.The relative floatability is important to determine how selectively the phosphate is separated from its impurities. The effects of pulp pH, solid content, reagents dosage(depressant, collector and co-collector) and conditioning time were investigated on the ratio of the modified rate constant of phosphate to the modified rate constant of iron(relative floatability). The results showed that a large dosage of depressant associated with a low value of collector resulted in a better relative floatability. Increasing the co-collector dosage, conditioning time and pH increased the relative floatability up to a certain value and thereafter resulted in diminishing the relative floatability. Meanwhile, the results indicated that increment of solid concentration increased the relative floatability in range investigated. It was also found that that maximum relative floatability(16.05) could be obtained in pulp pH, 9.32, solid percentage, 30,depressant dosage, 440 g/t, collector dosage, 560 g/t, co-collector dosage, 84.63 g/t and conditioning time,9.43 min.
基金supported by Climate Change Special Project of China Meteorological Administration(No CCSF2011-14)
文摘Based on the annual production data collected by the Statistic Center of the Ministry of Railways of the People＇s Republic of China, we calculated the energy saving and direct emission reductions of CO2, soot, SO2, CO, NOx and CnHm of electrified railways, and analyzed their dynamic characteristics during the period of 1975 2007. The results show that during this period, the annual mean values of energy saving is 1.23×10^6 tce, and direct emission reduction of CO2, soot, SO2, CO, NOx and CnHm are 4.267×10^6 t, 20.5×10^3 t, 3.0×10^3 t, 9.6×10^3 t, 67.9×10^3 t, and 6.9×10^3 t per year, respectively. The annual average increasing rates of energy saving is 139×10^3 tce, and direct emission reduction of CO2, soot, SO2, CO, NOx and CnHm are 483×10^3 t, 2.3×10^3 t, 0.34×10^3 t, 1.1×10^3 t, 7.7 ×10^3 t and 0.78×10^3 t per year, respectively. The electrified railways have played an important role in decreasing the energy consumption and air pollutant emissions of China＇s railway system. The results of this study could provide some reference knowledge for future reductions of energy consumption and waste gas emission in China＇s railway transportation.
文摘The article summarizes related research results and achievements of elastomer expansion device in railway bridge and puts forward a new idea of using polyurethane elastomer material to seal concrete bridge joints between adjacent spans in heavy haul railways. The new type expansion device is composed of polyurethane elastomer material and named TTXF （elastomer expansion joint）. In theory, researchers find out expansion joint deformation regularity between adjacent bridge spans through theoretical analysis and detection in heavy haul railways, such as Datong-Qinhuangdao Railway and Shenchi-Huanghua Port Railway. Fatigue tests prove that TTXF can adapt to permanent and dynamic deformation. On the other hand, it has been successfully applied in the test section of Central South of Shanxi Railway Passage and continuous monitoring has been conducted in extreme weather for over one year. The expansion joint has a good effect practically.
基金Supported by Grants from the Alcoholic Beverage Medical Research Foundation, Redox Biology Center, University of Nebraska-Lincoln, 2P20RR017675NIH grant, R01AA017738-01 to DHF
文摘Despite heavy consumption over a long period of time, only a small number of alcoholics develop alcoholic liver disease. This alludes to the possibility that other factors, besides alcohol, may be involved in the progression of the disease. Over the years, many such factors have indeed been identified, including iron. Despite being crucial for various important biological processes, iron can also be harmful due to its ability to catalyze Fenton chemistry. Alcohol and iron have been shown to interact synergistically to cause liver injury. Iron-mediated cell signaling has been reported to be involved in the pathogenesis of experimental alcoholic liver disease. Hepcidin is an iron-regulatory hormone synthesized by the liver, which plays a pivotal role in iron homeostasis. Both acute and chronic alcohol exposure suppress hepcidin expression in the liver. The sera of patients with alcoholic liver disease, particularly those exhibiting higher serum iron indices, have also been reported to display reduced prohepcidin levels. Alcohol-mediated oxidative stress is involved in the inhibition of hepcidin promoter activity and transcription in the liver. This in turn leads to an increase in intestinal iron transport and liver iron storage. Hepcidin is expressed primarily in hepatocytes. It is noteworthy that both hepatocytes and Kupffer cells are involved in the progression of alcoholic liver disease. However, the activation of Kupffer cells and TNF-α signaling has been reported not to be involved in the down-regulation of hepcidin expression by alcohol in the liver. Alcohol acts within the parenchymal cells of the liver to suppress the synthesis of hepcidin. Due to its crucial role in the regulation of body iron stores, hepcidin may act as a secondary risk factor in the progression of alcoholic liver disease. The clarification of the mechanisms by which alcohol disrupts iron homeostasis will allow for further understanding of the pathogenesis of alcoholic liver disease.
文摘The study was performed to determine whether the srum concentrations of IL （interleukin）-6 are elevated in patients with RA （rheumatoid arthritis） and to investigate the relationship between IL-6 levels and iron status in RA patients. 95 serum samples were obtained, 70 of them from patients with RA who had visited the department of Rheumatology at Al-Sadder medical city in Najaf governorate （Iraq） and 25 age and sex-matched healthy controls. The authors assessed the clinical parameters of the disease, including ESR （erythrocyte sedimentation rate）, CRP （C-reactive protein）, and RF （rheumatoid factor）. Serum levels of iron and TIBC （total iron binding capacity） were measured spectrophotometrically, while TS% （transferrin saturation percentage） and transferrin concentration were calculated mathematically. Serum concentrations of IL-6 （interleukin-6） and ferritin were measured using an ELISA （enzyme-linked immunosorbent assay）. The results of serum concentration of IL-6 （interleukin-6） and ferritin were significantly elevated （P 〈 0.0001） in patients with RA compared to those of healthy controls. On the other hand, serum concentrations of iron, TIBC （total iron binding capacity）, TS% （transferrin saturation percentage） and transferrin concentration were significantly decreased in patients with RA compared with those of healthy controls. These findings suggest that anemia is the most frequent observations in patients with RA and mostly associative with increasing level of interleukin-6.
