Because the general multi-wavelength UV-Visible absorbance detector cannot avoid the noise and drift resulting from the intensity fluctuation of the light source,a dual beam multi-wavelength UV-Visible detector based ...Because the general multi-wavelength UV-Visible absorbance detector cannot avoid the noise and drift resulting from the intensity fluctuation of the light source,a dual beam multi-wavelength UV-Visible detector based on CCD was designed.The ray of light source is divided into a signal ray and a reference ray by the beam splitter after it passes through the chopper.The signal ray shines into the sample cell.The signal ray passing through the sample cell falls onto a concave mirror which focuses it onto a slot that is imaged on one portion of CCD by a concave grating.The reference ray is imaged on the other portion of CCD by the concave grating after the slot.The signal spectrum,the reference spectrum and the dark current of CCD can be measured on the same CCD under the cooperation of the optical system and accessorial circuits.The real-time compensation for the signal spectrum by using the reference spectrum and the dark current of CCD can effectively depress the noise and drift of the detector.The short-term noise is 10 -5 AU and the drift is 10 -4 AU/h.展开更多
We report on the design,fabrication,and characterization of a micro plane-plane geometry CMOS device,which has a heat emitter and a heat receiver,capable of studying the near-field radiative heat transfer at a 550nm g...We report on the design,fabrication,and characterization of a micro plane-plane geometry CMOS device,which has a heat emitter and a heat receiver,capable of studying the near-field radiative heat transfer at a 550nm gap.Under high vacuum conditions,the heat emitter is heated by supplying driving currents and heated again after removing the heat receiver.The heating power difference between the two kinds of heating experiments indicates the existence of a proximity effect in the heat transfer between the emitter and the receiver.Our experiments pave the way towards overcoming the construction difficulty of plane-plane geometry with a nanometer gap.展开更多
文摘Because the general multi-wavelength UV-Visible absorbance detector cannot avoid the noise and drift resulting from the intensity fluctuation of the light source,a dual beam multi-wavelength UV-Visible detector based on CCD was designed.The ray of light source is divided into a signal ray and a reference ray by the beam splitter after it passes through the chopper.The signal ray shines into the sample cell.The signal ray passing through the sample cell falls onto a concave mirror which focuses it onto a slot that is imaged on one portion of CCD by a concave grating.The reference ray is imaged on the other portion of CCD by the concave grating after the slot.The signal spectrum,the reference spectrum and the dark current of CCD can be measured on the same CCD under the cooperation of the optical system and accessorial circuits.The real-time compensation for the signal spectrum by using the reference spectrum and the dark current of CCD can effectively depress the noise and drift of the detector.The short-term noise is 10 -5 AU and the drift is 10 -4 AU/h.
基金Supported by the National Natural Science Foundation of China under Grant Nos 60806038 and 61131004the National High Technology Research and Development Program of China under Grant Nos 2006AA040102 and 2006AA040106.
文摘We report on the design,fabrication,and characterization of a micro plane-plane geometry CMOS device,which has a heat emitter and a heat receiver,capable of studying the near-field radiative heat transfer at a 550nm gap.Under high vacuum conditions,the heat emitter is heated by supplying driving currents and heated again after removing the heat receiver.The heating power difference between the two kinds of heating experiments indicates the existence of a proximity effect in the heat transfer between the emitter and the receiver.Our experiments pave the way towards overcoming the construction difficulty of plane-plane geometry with a nanometer gap.
