Quantum dot is a kind of semiconductor nanoparticles, which has the unique optical properties of high fluorescence quantum yield, wide excitation spectrum, narrow emission spectrum, adjustable emission wavelength and anti-photobleaching. In recent years, it has been widely used in the area of health, food security, medicine, health care and environmental analysis. The basic features of quantum dots are briefly described, and the studies of small molecules trace organic pollutants analysis are reviewed based on quantum dot fluorescent technology including fluorescence linked immunosorbent assay, fluorescence resonance energy transfer (FRET) technology, and immune sensor technology. Finally, some existing problems and development direction in the field are presented.

In order to obtain the characteristics of the aerosol of Xuzhou city, based on CE-318, parameters of the optical characteristics of aerosol in Xuzhou suburb from July, 2013 to May, 2014 were employed for the analysis. The results show that: (1) Influenced by coal heating and straw burning, significant difference exists in each season, month and day. (2) Most aerosol particles contain moisture, which belong to the mixed type and anthropogenic pollution type. There exist few dry particles. (3) Fine particles with complicated composition play a dominant role except for May. (4) There exist more coarse particles in the spring than in the summer, which is equivalent in the autumn and winter. In addition, there exists rare dust weather during the analysis, fine particles make a greater contribution to the air pollution in Xuzhou city.

Aerosol optical properties are important for climate, environment and satellite remote sensing. The aerosol optical data of Tianjin coastal area from March to May in 2014 are measured by using the CE317 Solar Photometer, and further analyzed. The results show that aerosol optical depth (AOD) spectra are basically accord with Angstrom relationship. There are three basic types of AOD daily variations, which are rising type, stationary type and declining type. The mean value of 440 nm AOD in spring is 0.776, the Angstrom exponent α is 1.011, and the Angstrom turbidity coefficient β is 0.344. The results are compared with the data of Qingdao area in the Yellow Sea coastland, which shows the regional characteristics of aerosol optical properties.

Data of pollutant concentrations from November 1, 2013 to December 12, 2014 were collected from China National Environmental Monitoring Centre and employed to analyze the variation of pollutant concentrations in Beijing-Tianjin-Hebei region during APEC summit, 2011. The result shows that the annual mean concentrations of PM2.5, PM10, SO2, NO2 and CO are 95.3, 163.9, 54.7, 48.9 μg/m3, 1.5 mg/m3, respectively. Concentrations of these five kinds of pollutants are highest in winter and the lowest in summer, while different pollutant has different monthly distribution. During APEC summit, average concentrations of PM2.5, PM10, SO2, NO2 and CO are 66.1, 123.7, 33.2, 48.5 μg/m3, 1.2 mg/m3, respectively. The concentrations of PM2.5 during APEC summit account for 60.1% and 59.4% before and after APEC summit, respectively. The concentrations of CO, NO2 and SO2 during APEC summit are nearly the same as the concentrations before APEC summit, but increase significantly after APEC summit. Owing to the strict emission control, the concentrations of PM2.5, PM10, CO and NO2 in Beijing-Tianjin-Hebei region decrease by 40%, 35%, 15% and 10%, respectively.

In order to analyze the influence of external electric field on the molecular spectra and dissociation of methyl chloride, density functional (DFT) theory at B3LYP/6-311G++(d,p) level is used to investigate the influence on the molecular structure of the chloromethane molecule and dissociation properties under different external electric field (－0.03～0.03 a.u.), including molecular bond length, energy gap, IR spectra, dissociation curve and so on. The calculation results show that with external electric field increase from －0.03 a.u. to 0.03 a.u. step by step, on the Z direction(C-Cl line), C-Cl bond length increases and C-H bond length is almost the same. When the external electric field is equal to 0.01 a.u., the peak value is reached. The molecular energy gap increases and then decreases. The C-Cl stretching (STR) vibration frequency gradually decreases, while infrared (IR) vibration intensity gradually increases. Further research and analysis indicate that with the continuous increase of the external electric field (0～0.03 a.u.), the energy curve of CH3Cl molecule decreases gradually and the dissociation decreases too. When the external electric field is about 0.04 a.u., the dissociation energy is at the minimum, and the dissociation occurs. Therefore, it can control the degradation of the CH3Cl molecule by changing the external electric field.

In the satellite remote sensing of carbon dioxide (CO2), atmospheric environmental factor is the important factor affecting the inversion accuracy. The inversion condition is usually limited to the situation of the aerosol optical thickness less than 0.3. The higher requirement of the atmospheric conditions will seriously affect the application ability of our country’s CO2 satellite remote sensing data. For this kind of situation, based on principal component analysis (PCA), atmospheric CO2 of Beijing and Tianjin areas of China is inversed of high aerosol optical thickness, the CO2 column concentration obtained is compared with the product of GOSAT-Level2 in 2013, 2014. The root mean square error is 0.65% and 0.46%, respectively, and the correlation is 0.77 and 0.93, respectively.

Combining CALIOP aerosol optical depth (AOD) products and coincident AODs at two AERONET sites (i.e., Hangzhou－ZFU and SACOL), CALIOP Level 2 column AOD against AERONET AOD is validated. Intercomparison analyses show that the correlation coefficient between AOD at Hangzhou－ZFU (SACOL) and CALIPSO-derived AOD reaches as high as 0.87 (0.85), and the slope of the regression equation is 0.76 (0.92), indicating that CALIOP AOD is better enough to be applied to characterize the regional air pollution. Based on concurrent CALIOP level 3 monthly mean gridded AOD products (daytime and nighttime) and the MODIS Terra/Aqua level 3 monthly mean AOD dataset of the 8 years (2008～2015), the spatial and temporal variations of AOD over Southeast China and Northwest China are analyzed. Results show that Southeast China exhibits a significant seasonal and spatial variability. High AOD values are largely located in Yangtze River Delta and Pearl River Delta. The highest AOD occurs in spring, followed by summer, and then winter and autumn. In terms of monthly average AOD, MODIS tends to overestimate AOD compared with AERONET, ranging from 0.25 to 0.8. CALIOP AOD during night is commensurate with MODIS AOD. By comparison, much difference exists between the daytime CALIPSO AOD and MODIS AOD, which is as high as 0.45. Results from both MODIS and CALIPSO AODs suggest that the spatial distribution of AOD is very similar. To be more specific, the high AOD value is largely located in the Tarim Basin, Junggar Basin and Qaidam Basin. Meanwhile, the highest AOD value occurs in the spring, followed by summer, then winter and autumn. Overall, MODIS AOD values fluctuate significantly and are generally higher than CALIOP AOD values.

As medium of optical communication in the intelligent transportation system, LED light has wide application prospect. To ensure that the design of the visible light communication system has satisfactory performance, transmission characteristics of LED traffic lights in the communication channel should be fully understood, and construction of the channel model is a small cost and more flexible alternative means. The project of differential element is chosen to construct the channel model of direct link and reflection link, the impacts of typical weather condition, receiver position, transmission distance and different reflective pavement on systematic transmission performance are analyzed. Simulation results show that the effects of asphalt and water surface reflectance on the experimental result can be ignored in the channel modeling, while the impact of ice and snow road surface diffuse on reception should be considered; the closer the distance between car and light source is, the stronger the received signal is; at the same time, it is verified that the received signal is the best when the receiver is installed on the top of the car.

Web information extraction technology has been a hot topic in the field of information technology. Moreover, in recent years, DIV + CSS page layout method was commonly used in web design. Based on this, a simple and practical method for the text extraction of news web pages based on text features and page structure is presented. The text content block on the page is identified and extracted firstly, and then regular expression is used to filter the HTML tag of content block and the main text of the web page is extracted. Experimental results show that the method has great universal property and accuracy rate in text extraction.

With the high-speed development of science and technology, the demand for information is growing rapidly. Space laser communication is used more and more widely due to its advantages, such as faster rate of communication, smaller beam divergence angle of communication and better security and confidentiality. In the space laser communication system, the sky background radiation is the main background noise. Spot extraction has become a major impact on tracking accuracy in strong sky background conditions. Several methods for suppressing sky background were described, such as using atomic filters, reducing the caliber receiver, et al. Under the experimental conditions, coarse tracking spot is processed by using Otsu thresholding and centroiding algorithm. The effects of sky background light on coarse tracking spot are analyzed. The experimental results show that under the influence of the sky background, the Otsu thresholding method can accurately extract imaging spot, it also can effectively improve the coarse tracking accuracy.