Degradation of effective carrier-power-to-noise densityratio based on code trackingspectral sensitivitycoefficient for GNSS radio frequencycompatibilityin C band

The frequency band between 5 010 MHz and 5 030 MHz allocated as C band has been used as a candidate in the global navigation satellite systems （GNSS） along with more and more naviga- tion services in L band. The potential benefits and technical requirements of C band for satellite navi- gation have been analyzed before. However the degradation of effective carrier-power-to-noise densi- ty ratio（ A （C/No ）eu） based on code tracking spectral sensitivity coefficient（ CT_SSC ） as a compati- bility assessment methodology for potential GNSS radio frequency compatibility in C-Band has not been discussed clearly. So the compatibility of the signals in the C band between BeiDou （BD） B1 C and GPS L1C, L1C/A, Galileo E1Os as the interoperability or classical signals in L band is analyzed. Simulation results reveal the interference degree between BD III B1C and GPS L1C/A, L1C, Galileo E1OS. The results can also reveal that the multiplexed binary offset carrier （MBOC） and binary phase shift keying （BPSK） modulation is not appropriate for C band.

Selection of characteristic spectral bands for the analysis by the NIR correlation coefficient method

We analyzed the infrared 0R）-near infrared （NIR） 2D correlation spectra of drugs perturbed by temperature. By identification of functional groups by IR spectrum and by the correlation analysis of IR-NIR spectrum, we identified the characteristic spectral bands that were closely related to the structure of a drug substance of interest. These characteristic spectral bands were relatively less interfered by other ingredients for analysis by the NIR correlation coefficient method. With these characteristic spectral bands, the accuracy of screening illegally added Sildenafil citrate, Tadalafil and Metforrnin hydrochloride in Chinese patent drugs and healthcare products reached about 90%, which met the requirements of rapid screening.

Simulation of pavement roughness based on time domain model

In order to describe pavement roughness more intuitively and effectively, a method of pavement roughness simulation, i.e., the stochastic sinusoidal wave, is introduced. The method is based on the primary idea that pavement roughness is denoted as the sum of numerous sines or cosines with stochastic phases, and uses the discrete spectrum to approach the target stochastic process. It is a discrete numerical method used to simulate pavement roughness. According to a given pavement power spectral density （PSD） coefficient, under the condition that the character of displacement frequency based on the time domain model is in accordance with the given pavement surface spectrum, the pavement roughness is optimized to stochastic equivalent vibrations by computer simulation, and the curves that describe pavement roughness under each grade are obtained. The results show that the stochastic sinusoidal wave is suitable for simulation of measured pavement surface spectra based on the time domain model. The method of the stochastic sinusoidal wave is important to the research on vehicle ride comfort due to its rigorous mathematical derivation, extensive application range and intuitive simulation curve. Finally, a roughness index defined as the nominal roughness index （NRI） is introduced, and it has correlation with the PSD coefficient.

Scattering Properties of Atmospheric Aerosols over Lanzhou City and Applications Using an Integrating Nephelometer

The data, measured by a three-wavelength Integrating Nephelometer over Lanzhou City during the winters of 2001/2002 and 2002/2003 respectively, have been analyzed for investigating the scattering properties of atmospheric aerosols and exploring their relationship and the status of air pollution. The aerosol particle volume distribution is inverted with the measured spectral scattering coe?cients. The results show that the daily variation of the aerosol scattering coe?cients is in a tri-peak shape. The average ratio of backscattering coe?cient to total scattering coe?cient at 550 nm is 0.158; there exists an excellent correlation between the scattering coe?cients and the concentration of PM10. The average ratio of the concentration of PM10 to the scattering coe?cients is 0.37 g m?2, which is contingent on the optical parameters of aerosol particles such as the size distribution, etc.; an algorithm is developed for inverting the volume distribution of aerosol particles by using the histogram and Monte-Carlo techniques, and the test results show that the inversion is reasonable.

Characteristics of K_d (490) around Nansha Islands in the South China Sea

The diffusion attenuation coefficient for downwelling irradiance, Kd (490), is an important optical parameter of seawater. The optical property, Kd (490), around Nansha Islands in the South China Sea was analyzed based on optical data profiles measured with SPMR ( SeaWiFS Profiling Multichannel Radiometer ) and SMSR ( SeaWiFS Multichannel Surface Reference ) instrument in April and May, 1999. The results show that Kd (490) is closely correlated with chlorophyll-a concentration, Cchl.a, and that the vertical distribution of Kd (490) shows the strong stratification of the water column in this area. Kd (490) has a similar vertical co-variation as KL (490), the diffusive attenuation coefficient for upwelling radiance. Both coefficients increase with depth in the upper layer, where KL (490) is greater than Kd (490); and after a depth, approximatively at the chlorophyll maximum, they decrease with depth, with the former being smaller than the latter.