The polarization vector （PV） of an electromagnetic wave （EW） will experience a rotation in a region of spacetime perturbed by gravitational waves （GWs）. Based on this consideration, Cruise＇s group has built an ...The polarization vector （PV） of an electromagnetic wave （EW） will experience a rotation in a region of spacetime perturbed by gravitational waves （GWs）. Based on this consideration, Cruise＇s group has built an annular waveguide to detect GWs. We give detailed calculations of the rotations of polarization vector of an EW caused by incident GWs from various directions and in various polarization states, and then analyze the accumulative effects on the polarization vector when the EW passes n cycles along the annular waveguide. We reexamine the feasibility and limitation of this method to detect GWs of high frequency around 100 MHz, in particular the relic gravitational waves （RGWs）. By comparing the spectrum of RGWs in the accelerating universe with the detector sensitivity of the current waveguide, it is found that the amplitude of the RGWs is too low to be detected by the waveguide detectors currently operating. Possible ways of improvements on detection are suggested.展开更多
Circuit of the temperature measurement equipment was improved in order to develop temperature telemetering system for cultivating fruit facilities.The traditional temperature measuring equipments used in monitoring te...Circuit of the temperature measurement equipment was improved in order to develop temperature telemetering system for cultivating fruit facilities.The traditional temperature measuring equipments used in monitoring temperature changes in greenhouse include mercury column,merbromine column,kerosene column glass rod thermometer and mechanical inductive thermometer.Compared with the traditional method of temperature measurement the new system reduces the labor requirement and promotes precision monitoring and control of the temperature.In addition,the temperature in the greenhouse was very accurate especially at night or in rainy and snowy weather.This new temperature telemetering system will promote the development of the fruit protection cultivation.展开更多
文摘The polarization vector （PV） of an electromagnetic wave （EW） will experience a rotation in a region of spacetime perturbed by gravitational waves （GWs）. Based on this consideration, Cruise＇s group has built an annular waveguide to detect GWs. We give detailed calculations of the rotations of polarization vector of an EW caused by incident GWs from various directions and in various polarization states, and then analyze the accumulative effects on the polarization vector when the EW passes n cycles along the annular waveguide. We reexamine the feasibility and limitation of this method to detect GWs of high frequency around 100 MHz, in particular the relic gravitational waves （RGWs）. By comparing the spectrum of RGWs in the accelerating universe with the detector sensitivity of the current waveguide, it is found that the amplitude of the RGWs is too low to be detected by the waveguide detectors currently operating. Possible ways of improvements on detection are suggested.
基金the International S&T Cooperation Project of China(Project No.2012DFR30700)Special Fund for Agro-scientific Research in the Public Interest of China(Project No.200903019)+1 种基金The Ministry of Agriculture 948 Project of China(Project No.2011-Z40)Shandong agricultural improved variety project[No.(2010)6]and Taian scientific and technological development planning item(20075014).
文摘Circuit of the temperature measurement equipment was improved in order to develop temperature telemetering system for cultivating fruit facilities.The traditional temperature measuring equipments used in monitoring temperature changes in greenhouse include mercury column,merbromine column,kerosene column glass rod thermometer and mechanical inductive thermometer.Compared with the traditional method of temperature measurement the new system reduces the labor requirement and promotes precision monitoring and control of the temperature.In addition,the temperature in the greenhouse was very accurate especially at night or in rainy and snowy weather.This new temperature telemetering system will promote the development of the fruit protection cultivation.
