Ion-induced nucleation is one of the most significant pathway of aerosol particle formation in the atmosphere. Air molecules are radiated by the cosmic ray to generate a mass of initial primary ions which will quickly react with common trace air constituents, such as H2 O, H2 SO4 , HNO3 , NH3 and organic species to form more stable ions, called as cluster ions. Processes for aerosol formation are the competition between growth and evaporation. When the critical nucleus forms, the formed small aerosol particle growth become spontaneous. This critical diameter can be calculated and predicted to be about 1.6 nm with mass number more than 5000 amu at standard atmospheric condition. However, there exist many controversies on ion-induced nucleation to what extent of influencing global climate and new particle nucleation. More observations, molding and laboratory studies should be carried out to explore the mechanism of ion-induced nucleation clearly.

The dynamic relationship between the PM2.5 and other kinds of air pollutants was analyzed based on vector auto-regressive(VAR) model. Methods of Granger causality test, generalized impulse response function and variance decomposition analysis were used, based on the daily data of the ambient air quality from January 1, 2013 to December 31, 2014 in Xi’an city to investigate the effect of other kinds of air pollutants on the PM2.5. The results show that the air quality system composed of PM2.5 and other kinds of air pollutants is stable, the increase of sulfur dioxide concentration, nitrogen dioxide and carbon monoxide will lead to the increase of PM2.5 concentration. Sulfur dioxide has the greatest effect on PM2.5 and the increase of ozone concentration will make PM2.5 concentration decrease.

Based on the need of spaceflight design, a driver of rotating parts of a space-borne spectrometer was designed to accurately control the locating of the three motors. Motor’s accurate positioning is completed by resetting and fixed steps of micro switch. Fine adjustment of driving current is completed by using PWM mode. A platform was built and repeated tests were given to the design. The result showed that the system has high reliability and stability and can fulfill the requirements of accurate locating to make sure that the motors can finish the calibration according to the arrangement.

The data of seven parameters AQI, PM2.5, PM10, SO2 , NO2 , CO and O3 from 10 national-controlled automatic air quality monitoring station of Dalian from June to August in 2015 were analyzed to investigate the daily mean change of air quality index, the change of the hour, the special pollution date analysis and the correlation analysis between AQI and other parameters. The results showed that the excellent air quality in Dalian was 44.6%, the standard rate was 97.9% in the summer. The mean change of AQI days was large, and the change trend of AQI wave form was the same from June to August. For the special climate, AQI value maximum was 130.4 in August, and the AQI was significantly decreased due to the rainfall. The regularity of AQI hours from 00:00 to 07:00 when the data changed slowly, the data began to rise in rush hour, and AQI changed between peak and valley. Through correlation calculation, AQI, PM2.5, PM10 were significantly correlated, and CO, NO2 , O3 showed a good correlation with AQI. But the correlation between SO2 and AQI was not obvious, which is the basis for the treatment of air pollution in Dalian.

A new retrieval algorithm which can simultaneously retrieve atmospheric temperature profile, water vapor profile, surface skin temperature and surface emissivity is presented. The algorithm uses infrared radiances measured by Atmospheric Infrared Sounder (AIRS) in Yellow Sea region. The algorithm is applied to real AIRS observations and the results show that it is capable of retrieving high vertical resolution atmospheric temperature and water vapor. Surface skin temperature and surface emissity are simultaneously retrieved. The total precipitable water vapor (TPW) is computed by water vapor profile.

For the characteristic problem of bidirectional polarization reflectance distribution function (BPDF) in airborne polarimetric aerosol optic depth retrieval, the physics mechanism of BPDF is analyzed, and a BPDF model is put forward combining the characteristic BPDF model with the four classical models. This model is based on the shadow function and normalized difference vegetation index factor. The accuracy of new model is validated by the data of atmosphere multi-angle polarization radiometer, and the relative error is less than 9.9%. Compared with the three classic models, the new model shows good consistency when the viewing angle changes. Based on the accuracy of the new model, the relationship is simulated between the bias of polarized reflectance of land surface and the error of the retrieved aerosol optic depth. The results indicate that only less than 0.03 of the absolute error of the retrieved aerosol optic depth is caused when the polarized reflectance of land surface changed 4×10-4, and the application requirement of polarized aerosol retrieve can be satisfied.

In order to investigate the optical and physical properties and stability of the Mie scattering diffuser(MSD) in spatial environment, some reflective properties including the directional hemisphere reflectance (DHR), the bidirectional reflectance distribution function (BRDF) and the resistivity were measured. The results show that the reflectance achieves 80% at the band of 350～2000 nm, the differences of the reflectance is less than 0.024 per hundred nm. The variations rate of BRDF(10°～75°) is less than 5.2×10－4 at the band of 900 nm. The resistivity of MSD is about 1012{\\mkern 1mu}Ω·cm, it reduces the internal charging hazards to a great extent in the space. The experiment of radiation test shows that the MSD has the characteristic of stability of orbit radiation. Therefore, MSD can satisfy the requirements for space applications of use of the geosychronous orbit satellites.

In order to obtain multiple planes’ reconstructed images of digital holographic microscopy simultaneously, a method for multi-plane imaging in digital holographic microscopy was proposed to extend the depth of imaging space. The quadratic distorted phase factor with pre-established parameters was used to act on experimental recorded digital hologram and the reconstructed images at multiple planes would be obtained simultaneously under single reconstruction. Firstly the imaging transfer function which used the quadratic distorted phase factor was deduced according to the transfer function of Fresnel imaging system and the rules of selecting frequency domain filtering parameters were determined. Secondly the experimental recorded digital hologram was utilized to conduct frequency domain filtering in aiming to eliminate zero-order diffraction and conjugate image. Finally the quadratic distorted phase factor was used to act on the filtered digital hologram to conduct Fresnel reconstruction. Compared with other methods, it needed single reconstruction to obtain multiple planes’ in-focus images by the method and the reconstruction distance could be chosen in arbitrary, also the reconstructed images could be got without the interference of the zero-order diffraction and conjugate image.

The appearance of measurement error is inevitably caused by steel rolling, steel slag, steel scale in the temperature monitoring of molten steel in RH refining furnace. Through the accurate discrimination and cluster analysis of the molten steel and non steel material, such as design, key parameters of the sampling area, gray value correction and the temperature model, the actual temperature of the molten steel can be obtained, and temperature variation curves are given to improve the accuracy and continuity of temperature measurement, and easily achieve precision steelmaking and scientific steelmaking.

The important role of single-photon detector for laser ceilometers is briefly introduced. On the basis of the basic working principle of single-photon detector (single-photon avalanche diode, SPAD), a passive suppression circuit of SPAD is built. The experiment shows that the dead time of SPAD is above 2 μs, only applicable to the occasion when single-photon counting rate is less than 500 kHz. In order to shorten the dead time of the single-photon detector, improve single-photon counting rate, the mixed suppression circuit of avalanche passive quenching and voltage active recovery is designed. Through the precise timing control, the dead time of the detector is shortened to 100 ns, single-photon counting rate up to 10 MHz. In theory, the spatial resolution of the laser ceilometer can be up to 15 m, mixed quenching circuit of single-photon detector SPAD for the performance of laser ceilometer and smooth development has important significance.