In light of the needs of China’s foreign economic and trade development and the regulations of the Law of Commodity Inspection, the State Administration of Import and Export Commodity Inspection issued a readjusted C...In light of the needs of China’s foreign economic and trade development and the regulations of the Law of Commodity Inspection, the State Administration of Import and Export Commodity Inspection issued a readjusted Category List of Import and Export Commodities Subject to Inspection Implemented by the Institutions of Commodity Inspection, and it is implemented officially on July 1, 1995. The new category list is compiled on the classified basis of the Commodity Names and Code Coordination System used widely around the world. The commodity code and name are identical to the Commodity List of the Custom Statisticsrelating to which there are 2。展开更多
This paper puts forward the concept of double semi-active vibration isolation systemutilizing the 'on-off' active damper and the 'on-off' active spring. Applying KBM Asympto-tic method, the vibration ...This paper puts forward the concept of double semi-active vibration isolation systemutilizing the 'on-off' active damper and the 'on-off' active spring. Applying KBM Asympto-tic method, the vibration of the system in case of weak semi-active control is studied. ln pcactice, there are two types of vibration isolation. One is to isolate the transmitting of the cyclicunbalanced force generated by the revolving machine to the surroundings. The other is to isolatethe transmitting of the vibration displacement of the surroundings to precise equipment. Deduc-ing the influence of the roadway unflatness on vehicles also belongs to this type. For the firsttype of isolation system, the damper always dissipates energy, and the total work done by the spring in a vibration cycle is zero. For the second type of isolation system, the work done by the damper sometimes is positive, and sometimes negative. The damper dissipates less energy. The work done by the spring in a vibration cycle isn't zero, and it is usually positive. ln thispaper, the vibration isolation is refered to the second type. .展开更多
In January, six universities in Shanghai held independent admission tests to select students from more than 10,000 appli- cants. At four of the universities, Chinese was not a test subject or science
文摘In light of the needs of China’s foreign economic and trade development and the regulations of the Law of Commodity Inspection, the State Administration of Import and Export Commodity Inspection issued a readjusted Category List of Import and Export Commodities Subject to Inspection Implemented by the Institutions of Commodity Inspection, and it is implemented officially on July 1, 1995. The new category list is compiled on the classified basis of the Commodity Names and Code Coordination System used widely around the world. The commodity code and name are identical to the Commodity List of the Custom Statisticsrelating to which there are 2。
文摘This paper puts forward the concept of double semi-active vibration isolation systemutilizing the 'on-off' active damper and the 'on-off' active spring. Applying KBM Asympto-tic method, the vibration of the system in case of weak semi-active control is studied. ln pcactice, there are two types of vibration isolation. One is to isolate the transmitting of the cyclicunbalanced force generated by the revolving machine to the surroundings. The other is to isolatethe transmitting of the vibration displacement of the surroundings to precise equipment. Deduc-ing the influence of the roadway unflatness on vehicles also belongs to this type. For the firsttype of isolation system, the damper always dissipates energy, and the total work done by the spring in a vibration cycle is zero. For the second type of isolation system, the work done by the damper sometimes is positive, and sometimes negative. The damper dissipates less energy. The work done by the spring in a vibration cycle isn't zero, and it is usually positive. ln thispaper, the vibration isolation is refered to the second type. .
文摘In January, six universities in Shanghai held independent admission tests to select students from more than 10,000 appli- cants. At four of the universities, Chinese was not a test subject or science
