Chromium ore fines containing coal (COFCC) can be rapidly heated by microwave to conduct the voluminal reduction, which lays a foundation of getting sponge ferrochromium powders with a lower content of C. Under the co...Chromium ore fines containing coal (COFCC) can be rapidly heated by microwave to conduct the voluminal reduction, which lays a foundation of getting sponge ferrochromium powders with a lower content of C. Under the conditions of COFCC with n(O)-n(C) (molar ratio) as 1.00-0.84 and n(SiO2)-n(CaO) as 1.00-0.39, the samples were heated by 10 kW microwave power to reach the given temperatures and held for different times respectively. The results show that the low-C-Cr ferrochromium metal phase in the reduced materials forms before the high-C-Cr ferrochromium metal phase does. With increasing temperature the C content of ferrochromium metals is in a positive correlation with the content of Cr. The C content of ferrochromium metal in reduced materials is 0-10.07% with an average value of 4.68%. With the increase of holding time the Cr content in ferrochromium metals is in a negative correlation with the content of C, while the content of Fe changes in the contrary way. In the microwave field the kinetic conditions of carburization are closely related with the temperature of microwave heating, holding time and carbon fitting ratio.展开更多
Employing remote sensing method to interpret the building volumetric ratio and aerosol status in Guangzhou, China. The relation between them and identified characteristics of their spatial distribution was analyzed. R...Employing remote sensing method to interpret the building volumetric ratio and aerosol status in Guangzhou, China. The relation between them and identified characteristics of their spatial distribution was analyzed. Results showed that building density and aerosol status are strongly correlated. It is indicated that the resistance of building to aerosol diffusing is one of factors influencing air pollution in urban area. On the basis of calculated results, building voluminous ratio of 5 6 is taken as the threshold impacting on aerosol diffusing, so the building voluminous ratio of Guangzhou should be limited to less than 5 6 in order to alleviate air pollution.展开更多
Purpose: To describe the aspects of the positive diagnosis of large goiters. Patients and Methods: We conducted a retrospective and prospective study including 115 patients from January, 2009 till December, 2014 (6 ye...Purpose: To describe the aspects of the positive diagnosis of large goiters. Patients and Methods: We conducted a retrospective and prospective study including 115 patients from January, 2009 till December, 2014 (6 years) in Central Hospital of University of Point G in Bamako (Mali). The diagnosis of large goiters was based on the measurements of the anterior neck swelling. Thus large goiter was defined as any goiter including the height or width was greater than or equal to 10 cm (centimeters). Results: We operated 115 cases of large goiters on 760 goiters operated either 15.1%. The average age of patients was 44, 43 years ±14, 3 with extremes of 9 and 80 years. There was 101 women (87.8%) and 14 men (12.2%) with a sex ratio of 7.2 in favor of women. The signs of compression were dyspnea in 40% of cases (46/115), dysphonia in 13.0% (15/115), and dysphagia in 8.6% (10/115). The average height of goiter was 12.1 cm ± 3.5 cm with extremes of 10 and 29 cm and the average width was 14.4 cm ± 5.4 cm with extremes of 10 and 32 cm. Thyroid ultrasound found large goiters multinodular in 100%. Cervical radiography found the tracheal deviation in 48.2% (42/87), tracheal compression in 20.6% (18/87), plunging goiters in 11.5% (10/87). Cytology found a benign goiter in 97.4% of cases (112/115), malignant (thyroid cancer) in 2.6% of cases (3/115). Conclusion: Diagnosis of large goiters was based on the measurement of the swelling in our context. The signs of compression are the severity of this condition.展开更多
The kinetics of voluminal reduction of chromium ore fines containing coal （COFCC） by microwave heating was studied. When the molar ratio of carbon to oxygen was 0.84 and that of CaO to SiO2 was 0.39 in COFCC, the te...The kinetics of voluminal reduction of chromium ore fines containing coal （COFCC） by microwave heating was studied. When the molar ratio of carbon to oxygen was 0.84 and that of CaO to SiO2 was 0.39 in COFCC, the temperature rising rate of COFCC by microwave heating was 62.5 ℃/min, 68.75 ℃/min, 70. 59 ℃/min, and 72.22 ℃/min at 1 000 ℃, 1 100 ℃, 1 200 ℃, and 1 300 ℃, respectively. The results show that the voluminal re duction of COFCC by microwave heating at solid-solid phase is first order reaction, with the apparent activation energy of 51. 480 kJ/mol. The limiting step of reaction rate for the overall reaction is the mass transfer of CO in the reduced product layer between dielectric particles of chromium ore and coal.展开更多
基金Project(50474083) supported by the National Natural Science Foundation of ChinaProject supported by the Baoshan Iron & Steel Co. Ltd. of China
文摘Chromium ore fines containing coal (COFCC) can be rapidly heated by microwave to conduct the voluminal reduction, which lays a foundation of getting sponge ferrochromium powders with a lower content of C. Under the conditions of COFCC with n(O)-n(C) (molar ratio) as 1.00-0.84 and n(SiO2)-n(CaO) as 1.00-0.39, the samples were heated by 10 kW microwave power to reach the given temperatures and held for different times respectively. The results show that the low-C-Cr ferrochromium metal phase in the reduced materials forms before the high-C-Cr ferrochromium metal phase does. With increasing temperature the C content of ferrochromium metals is in a positive correlation with the content of Cr. The C content of ferrochromium metal in reduced materials is 0-10.07% with an average value of 4.68%. With the increase of holding time the Cr content in ferrochromium metals is in a negative correlation with the content of C, while the content of Fe changes in the contrary way. In the microwave field the kinetic conditions of carburization are closely related with the temperature of microwave heating, holding time and carbon fitting ratio.
文摘Employing remote sensing method to interpret the building volumetric ratio and aerosol status in Guangzhou, China. The relation between them and identified characteristics of their spatial distribution was analyzed. Results showed that building density and aerosol status are strongly correlated. It is indicated that the resistance of building to aerosol diffusing is one of factors influencing air pollution in urban area. On the basis of calculated results, building voluminous ratio of 5 6 is taken as the threshold impacting on aerosol diffusing, so the building voluminous ratio of Guangzhou should be limited to less than 5 6 in order to alleviate air pollution.
文摘Purpose: To describe the aspects of the positive diagnosis of large goiters. Patients and Methods: We conducted a retrospective and prospective study including 115 patients from January, 2009 till December, 2014 (6 years) in Central Hospital of University of Point G in Bamako (Mali). The diagnosis of large goiters was based on the measurements of the anterior neck swelling. Thus large goiter was defined as any goiter including the height or width was greater than or equal to 10 cm (centimeters). Results: We operated 115 cases of large goiters on 760 goiters operated either 15.1%. The average age of patients was 44, 43 years ±14, 3 with extremes of 9 and 80 years. There was 101 women (87.8%) and 14 men (12.2%) with a sex ratio of 7.2 in favor of women. The signs of compression were dyspnea in 40% of cases (46/115), dysphonia in 13.0% (15/115), and dysphagia in 8.6% (10/115). The average height of goiter was 12.1 cm ± 3.5 cm with extremes of 10 and 29 cm and the average width was 14.4 cm ± 5.4 cm with extremes of 10 and 32 cm. Thyroid ultrasound found large goiters multinodular in 100%. Cervical radiography found the tracheal deviation in 48.2% (42/87), tracheal compression in 20.6% (18/87), plunging goiters in 11.5% (10/87). Cytology found a benign goiter in 97.4% of cases (112/115), malignant (thyroid cancer) in 2.6% of cases (3/115). Conclusion: Diagnosis of large goiters was based on the measurement of the swelling in our context. The signs of compression are the severity of this condition.
基金Item Sponsored by National Natural Science Foundation of China and Baoshan Iron and Steel Co Ltd of China(50474083)
文摘The kinetics of voluminal reduction of chromium ore fines containing coal （COFCC） by microwave heating was studied. When the molar ratio of carbon to oxygen was 0.84 and that of CaO to SiO2 was 0.39 in COFCC, the temperature rising rate of COFCC by microwave heating was 62.5 ℃/min, 68.75 ℃/min, 70. 59 ℃/min, and 72.22 ℃/min at 1 000 ℃, 1 100 ℃, 1 200 ℃, and 1 300 ℃, respectively. The results show that the voluminal re duction of COFCC by microwave heating at solid-solid phase is first order reaction, with the apparent activation energy of 51. 480 kJ/mol. The limiting step of reaction rate for the overall reaction is the mass transfer of CO in the reduced product layer between dielectric particles of chromium ore and coal.
