It is often required to know which roadway （adjustment roadway） resistances and how much values of the resis- tances should be changed to make the airflow rates in roadways （target roadways） to certain required va...It is often required to know which roadway （adjustment roadway） resistances and how much values of the resis- tances should be changed to make the airflow rates in roadways （target roadways） to certain required values in the practice of mine ventilation. In this case, the airflow rates of the target roadways and the resistances of the roadways other than the ad- justment roadways are the given conditions and the resistances of the adjustment roadways are the solutions to be found. No straightforward method to solve the problem has been found up to now. Therefore, trial and error method using the ventilation network analysis program is utilized to solve the problem so far. The method takes long calculation time and the best answer is not necessarily obtained. The authors newly defined ＂airflow element＂ as an element of the ventilation network analysis. The resistances that satisfy the airflow requirements can be calculated straight forwardly by putting the function of the airflow element into the ventilation network analysis. The air power required for the ventilation can be minimized while meeting the airflow requirements by the advanced application of the method. The authors made the computer program fulfill the method. The program was applied to actual ventilation network and it was found that the method is very practical and the time required for the analysis is short.展开更多
When World War I ended in 1918 the aviators wanting to fly higher and further and they started a raced in which everyone wanted to be first. The Spanish pilots were initially excluded by the Moroccan War, which demand...When World War I ended in 1918 the aviators wanting to fly higher and further and they started a raced in which everyone wanted to be first. The Spanish pilots were initially excluded by the Moroccan War, which demanded all available air forces be used to put an end to the conflict. Motivated by the successes of The Alhucemas amphibious landing, one of best Spanish aviators, Major Ramon Franco presented to the Government in 1925 a project to undertake a flight to Argentina across the South Atlantic Ocean in a DornierJ Wal seaplane. In the memorandum, Franco said： The Spain-Argentina flight would be a worthwhile trial and verification of air navigation. It would also serve to let the entire world know of the merits of our Aviation and allow us to occupy the aeronautical place that belongs to us in aeronautics. It would also help us strengthen our ties with our brothers at the other side of the ocean. The DornierJ Walwas named ＂Plus Ultra＂ referring to the Discovery of America. The route should be Palos de la Frontera-Las Palmas de Gran Canaria-Cape Verde islands-Fernando Noronha island-Pernambuco-Rio de Janeiro-Montevideo and Buenos Aires. Franco reasoned that the best time of year to make the flight was from December to April. The raid started in the city Palos de la Frontera on 22 January 1926 and ended in Buenos Aires on February 9, after flying 10,825 kilometers in 59 hours and 48 minutes.展开更多
China has developed an airborne gravimetry system based on SINS/DGPS named SGA-WZ, the first system in which a strap- down inertial navigation system （SINS） has been used for airborne gravimetry in China. This gravi...China has developed an airborne gravimetry system based on SINS/DGPS named SGA-WZ, the first system in which a strap- down inertial navigation system （SINS） has been used for airborne gravimetry in China. This gravity measurement system consists of a strap-down inertial navigation system and a differential global positioning system （DGPS）. In April 2010, a flight test was carried out in Shandong Province of China to test the accuracy of this system. The test was designed to assess the re- peatability and accuracy of the system. Two repeated flights and six grid flights were made. The flying altitude was about 400 m. The average flying speed was about 60 m/s, which corresponds to a spatial resolution of 4.8 km when using 160-s cutoff low-pass filter. This paper describes the data processing of the system. The evaluation of the internal precision is based on repeated flights and differences in crossover points. Gravity results in this test from the repeated flight lines show that the re- peatability of the repeat lines is 1.6 mGal with a spatial resolution of 4.8 kin, and the internal precision of grid flight data is 3.2 mGal with a spatial resolution of 4.8 km. There are some systematic errors in the gravity results, which can be modeled using trigonometric function. After the systematic errors are compensated, the precision of grid flight data can be better than 1 mGal.展开更多
文摘It is often required to know which roadway （adjustment roadway） resistances and how much values of the resis- tances should be changed to make the airflow rates in roadways （target roadways） to certain required values in the practice of mine ventilation. In this case, the airflow rates of the target roadways and the resistances of the roadways other than the ad- justment roadways are the given conditions and the resistances of the adjustment roadways are the solutions to be found. No straightforward method to solve the problem has been found up to now. Therefore, trial and error method using the ventilation network analysis program is utilized to solve the problem so far. The method takes long calculation time and the best answer is not necessarily obtained. The authors newly defined ＂airflow element＂ as an element of the ventilation network analysis. The resistances that satisfy the airflow requirements can be calculated straight forwardly by putting the function of the airflow element into the ventilation network analysis. The air power required for the ventilation can be minimized while meeting the airflow requirements by the advanced application of the method. The authors made the computer program fulfill the method. The program was applied to actual ventilation network and it was found that the method is very practical and the time required for the analysis is short.
文摘When World War I ended in 1918 the aviators wanting to fly higher and further and they started a raced in which everyone wanted to be first. The Spanish pilots were initially excluded by the Moroccan War, which demanded all available air forces be used to put an end to the conflict. Motivated by the successes of The Alhucemas amphibious landing, one of best Spanish aviators, Major Ramon Franco presented to the Government in 1925 a project to undertake a flight to Argentina across the South Atlantic Ocean in a DornierJ Wal seaplane. In the memorandum, Franco said： The Spain-Argentina flight would be a worthwhile trial and verification of air navigation. It would also serve to let the entire world know of the merits of our Aviation and allow us to occupy the aeronautical place that belongs to us in aeronautics. It would also help us strengthen our ties with our brothers at the other side of the ocean. The DornierJ Walwas named ＂Plus Ultra＂ referring to the Discovery of America. The route should be Palos de la Frontera-Las Palmas de Gran Canaria-Cape Verde islands-Fernando Noronha island-Pernambuco-Rio de Janeiro-Montevideo and Buenos Aires. Franco reasoned that the best time of year to make the flight was from December to April. The raid started in the city Palos de la Frontera on 22 January 1926 and ended in Buenos Aires on February 9, after flying 10,825 kilometers in 59 hours and 48 minutes.
基金supported by the National High-Tech Research&Development Program of China(Grant No.2006AA06A202)the Youth Innovation Foundation of China Aero Geophysical Survey&Remote Sensing Center for Land and Resources(Grant No.2010YFL05)
文摘China has developed an airborne gravimetry system based on SINS/DGPS named SGA-WZ, the first system in which a strap- down inertial navigation system （SINS） has been used for airborne gravimetry in China. This gravity measurement system consists of a strap-down inertial navigation system and a differential global positioning system （DGPS）. In April 2010, a flight test was carried out in Shandong Province of China to test the accuracy of this system. The test was designed to assess the re- peatability and accuracy of the system. Two repeated flights and six grid flights were made. The flying altitude was about 400 m. The average flying speed was about 60 m/s, which corresponds to a spatial resolution of 4.8 km when using 160-s cutoff low-pass filter. This paper describes the data processing of the system. The evaluation of the internal precision is based on repeated flights and differences in crossover points. Gravity results in this test from the repeated flight lines show that the re- peatability of the repeat lines is 1.6 mGal with a spatial resolution of 4.8 kin, and the internal precision of grid flight data is 3.2 mGal with a spatial resolution of 4.8 km. There are some systematic errors in the gravity results, which can be modeled using trigonometric function. After the systematic errors are compensated, the precision of grid flight data can be better than 1 mGal.
