It is reported that although the housing market and construction market in the United States are still sluggish, the increase in timber exports to China has eased the impact of the economic crisis on these two markets. The wood industry in the United States has become one of the “surprising†highlights of the U.S. economy.
According to the report, the U.S. timber exports to China reached 270 million U.S. dollars in 2010, which is more than double the export value in 2009. This also made China more than Japan and Canada become the largest US timber export market. According to industry sources in the US timber industry, US timber exports to Japan increased by 15% last year, but by comparison, exports to China increased by about 300%.
Most of the objects of US timber exports to China are large-scale private timber companies in China, and most of the wood comes from private forests in the Pacific Northwest of the United States. Logs were transported to the port of Olympia for shipping, and dozens of jobs can be created in the process. In Washington, USA, the surge in timber export trade has also made an important contribution to local public taxation. “This (tax) will be used for school construction and used to pay for (students’) university tuition.â€
However, the report also pointed out that not everyone is "celebrating for this purpose." As China “opens its purseâ€, the price of wood is not only unstable but even rising. This also means that wood processors in the United States have to buy logs at higher prices, and the reduction in the number of housing construction further causes them to lose their profits, which also causes some processors to choose to change or close the doors. Some American lumber sellers said: “The problem that logellers have to face is that they very much want to continue their business, but China’s impact on raw material prices makes them unprofitable.â€
The report also pointed out that analysts expect that as long as the Russian timber export tariffs remain unchanged, the US timber exports to China will continue to increase.
The vibration sensor(Vibration Transmitter) is one of the key components in the testing technology of Vibration Measurement. Its main function is to receive the mechanical quantity and convert it into a proportional electric quantity. Because it is also an electromechanical conversion device. So we sometimes call it a transducer, a vibration pickup, etc.
Commonly used vibration sensors are as follows:
1. Piezoelectric resonant
The piezoelectric sheet is used to receive the vibration signal, and the resonance frequency of the piezoelectric sheet is relatively high. In order to reduce the resonance frequency, it is realized by increasing the mass of the piezoelectric sheet vibrating body, and using a spring ball instead of an appendage to reduce the two resonance frequencies and enhance the vibration effect. Its advantages are high sensitivity and simple structure. However, the signal needs to be amplified and sent to a TTL circuit or a single-chip microcomputer circuit, but it is enough to use a triode single-stage amplification
2. mechanical vibration
In the traditional vibration detection method, after being vibrated, the spring ball vibrates at a reduced amplitude for a long time, and this vibration is easy to be detected by the detection circuit. The vibration output switch signal is determined by the output impedance and the resistance value of the matching output. According to the input impedance of the detection circuit, it can be made into a high-impedance output mode.
3. Micro Vibration Sensor
The mechanical vibration sensor is miniaturized, the vibration body is carbonized and sealed, and its working performance is more reliable. The output switching signal is directly connected with the TTL circuit and or the input circuit of the single-chip microcomputer, and the circuit structure is simple. The output impedance is high, and the quiescent working current is small.
Advantages of Vibration Sensors
1. Small size and light weight. It can be applied to some vibration test systems that are greatly affected by the additional mass.
2. It has a wider response frequency range of 4Hz-2000Hz than the magnetoelectric speed sensor, and the mechanical moving parts are not easy to damage
If you have any questions about the vibration sensor, please contact us, we will provide you with professional and timely answers.
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