In the measurement, the amount that can be directly read out by the measuring instrument is called the direct measurement amount; the amount obtained by the direct measurement amount and some constants and function operations is called the indirect measurement amount. The number of significant digits of the direct measurement (the last digit of the significant digit should be the estimated digit) is determined by the accuracy (minimum scale) of the measuring instrument. That is, the maximum absolute error of the measuring instrument is obtained from the accuracy of the instrument (hereinafter referred to as the error), and the error is only reserved for one significant digit. Finally, the position where the effective digit of the error is located determines that the measurement is valid. The cutoff digits. For example, if the length of a wooden stick is measured by a ruler with a minimum scale of i=1mm, the length of a wooden stick is 300mm, because the maximum error of the ruler is $=i/2=0.5mm, the cut-off position of the effective number of the measurement should be 1 At /10mm, it should be expressed as L=300.0mm. Note that the /00 after the decimal point must be written here and cannot be omitted.
This product adopts the unique structure design of horizontal series connection of all-glass vacuum collector tubes, cascade heating of Roots water ring vacuum unit, and one-way circulation of water circuit, which separates the warm water tank and the boiling water tank, which is the first in China.
The temperature difference in Xinjiang changes drastically every day, with dry and less rain, hot in summer, and extremely cold in winter. The wind speed in the whole region is large in winter and spring, followed by summer and autumn. Xinjiang's solar energy reserves are very rich, which provides unique advantages for the use of solar energy. In recent years, the Asia-Europe optical cable, West-Iran and One-bird optical cable, as well as the southern and northern Xinjiang optical cables in our area have passed through most of the areas where there is no electricity. This provides a useful place for photovoltaic power. In the above-mentioned optical cable project, our unit has undertaken the installation of photovoltaic power for more than 100 unmanned stations.