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Under different ambient temperatures, the thermal aberration certainly affects the imaging quality of infrared multi-spectral camera. Therefore, an athermalized model of infrared multi-spectral cameras is established, and in this model the ambient infrared multispectral camera is equivalent to a separated dual-lens optical system. In the case of the fixed focal length, the influence of the back focal length on the change of the focal power of the front lens and back lens is analyzed. Now, the variation range of the front and rear lens interval is assumed to be restricted. When the back focal length is smaller than the focal length, the ratio of the absolute value of the focal power of the front lens to the absolute value of the focal power of the back lens decreases with the back focal length increasing. The material of the front lens and the back lens have a longer interval on the thermogram. When the back focal length is greater than the focal length, the scenario becomes exactly opposite. Combined with the judgment method of the positive value and negative value of the focal power on the thermogram, the selection range of materials is constrained by the positive value, negative value, and absolute value of focal power, thus realizing the rapid selection of the optical materials. This method is used to design an athermalized infrared multispectral camera with a waveband of 8–14 μm, a focal length of 50 mm, and an F number of 1.4 in a range from –40 ℃ to +60 ℃. Through the simulation analysis, the value of the athermalized infrared multispectral camera, at the Nyquist frequency of 30 lp/mm reaches 0.39, which is close to the diffraction limit; the root mean square radius of the diffuse spot is smaller than the Airy spot radius of 19.17 μm; the axial aberration is less than 0.02 mm, and the design results show that this method can make the long back-focus infrared optical system maintain stable imaging quality in a large temperature range. The SF6 gas is detected experimentally, and the experimental results demonstrate the excellent optical performance of the system.

The problem of detecting the biological aerosol at low elevation angle is analyzed and discussed by using MODTRAN model. First of all, the atmospheric model and profile of MODTRAN model are introduced for the biological aerosol detection by Fourier transform infrared (FTIR) spectroscopy. According to the passive detection of biological aerosol by FTIR spectroscopy, the radiation brightness difference L between the background and the target biological aerosol is calculated by using the radiative transfer theory and the simplest three-layer model. The signal value 2Lt under the actual circumstance is derived from the derivative of L combined with the noise equivalent spectral radiance value of the spectrometer. Finally, the detection limit of biological aerosol for each atmospheric mode is predicted with the passive remote sensing method. The limit concentration of detection for each atmospheric mode is different due to the differences in boundary layer temperature, transmittance, and background radiation brightness of atmospheric model, and it is also related to the absorption coefficient of biological aerosol. It is shown that the passive remote sensing of FTIR technology can detect the presence of the biological aerosol. Therefore, the detection of the biological aerosol is feasible. It presents a method of detecting the biological aerosol cloud under the actual circumstance.

In order to study the carrier transporting properties in organic semiconductors (OSCs), the samples of single layer structure ITO/NPB/Ag are prepared, and the corresponding admittance model in theory is built. Impedance samples of the structure under different DC bias voltages are obtained by small sinusoidal signal frequency test method. The particle swarm optimization (PSO) algorithm, in which fitness function includes both the real part and the imaginary part of OSC impedance, is used to identify the model parameter including dispersion coefficient M, α and charge-carrier transit time τdc. To validate the proposed method, an equivalent circuit model of the structure, whose time constant τc is identified by least squares method, is built. Two single-layer structures, whose NPB thickness values are respectively 1000 nm and 1200 nm, are tested. Test results show that the charge-carrier transit time τdc is proportional to the time constant τc and the two hole mobility μdc values both satisfy the famous Poole-Frenkel formula.

The magnetism, stabilities and phase transition of Ru in hcp, fcc, bct and bcc structures are investigated with detailed first-principles calculations based on density-functional theory and quasiharmonic lattice dynamics approximation. Magnetic ground states and stability ranges of various phases are obtained. Calculated results indicate that the non-magnetic (NM)-hcp structure is the most stable in the entire pressure range at zero temperature, and the structural transition cannot be induced by pressure alone. NM-fcc structure is a metastable phase of bulk Ru, while both the NM-bcc and ferromagnetic (FM)-bct structures are dynamically unstable. At high pressure and temperature, a transformation from NM-hcp to NM-fcc structure will occur. Finally, the pressure-temperature phase diagram of Ru is presented.

The concentration of carbon dioxide in the atmosphere has been increasing continuously. This is a big concern with respect to the environment and climate changes and so on. A kind of ground-based low-resolution remote sensing system and a real-time spectral inversion method are presented for the real-time remote sensing column concentration of carbon dioxide. Based on continuous observation of this system in Hefei, the total atmospheric transmittance is real-timely obtained from the solar absorption spectrum. The column concentrations of carbon dioxide and oxygen are inversed from total atmospheric transmittance by line-by-line nonlinear least squares spectral inversion algorithm. The column concentration of oxygen is used as internal standard function to obtain the column average volume mixing ratio of carbon dioxide in total dry air column, and the precision is better than 3%.The average volume mixing ratio of carbon dioxide in dry-air column, from 12: 00 to 15:00 on September 25, 2012, is compared with observation results by Japanese greenhouse-gases satellite over the site in this period, showing that the relative deviation is less than 1%. Obviously, it is an effective way to measure greenhouse gases concentration with high precision and accuracy.

Two sound field separation techniques based on equivalent source method are proposed:one is based on the double-layer pressure measurements and the other is based on the single-layer pressure-velocity measurements. In this paper, a sound field separation technique based on equivalent source method but using the double-layer velocity measurements is proposed. First, the theoretical description of this technique is given, and then numerical simulations and experiments are conducted to demonstrate the validity of this technique. By comparison with the technique based on double-layer pressure measurements, the superiority of the proposed technique in separating particle velocity field is shown. And also, in the numerical simulations, the influences of the strength of disturbing source and the distance between two measurement planes on separation accuracy are investigated.

An instrument based on Fourier transform infrared spectrometer is developed, which is capable of simultaneously measuring carbon dioxide (CO2) and 13CO2 in a single air sample with higher precision. The temperature and pressure effect on the values of CO2 and 13CO2 are investigated. Both the standard gas and air sample gas are continuously measured using this method. Precision and accuracy are improved by comparing with the measurements of standard gas after correction using the law of temperature and pressure effect on the values of CO2 and 13CO2.

The incoherent sound field obtained by scanning measurement cannot be used directly for nearfield acoustic holography to reconstruct the sound field. And therefore, the incoherent sound field needs to be decomposed into fully coherent partial fields. In previous methods, the pressure is used as reference to obtain the partial fields. In this paper, the pressure gradient is used as the reference for the partial field decomposition. Because the pressure gradient decays faster than the pressure, the interaction of the pressure gradient between the incoherent sources is weaker than that of the pressure, which may improve the effect of the partial field decomposition. A numerical simulation and an experiment are conducted to test the feasibility of the method. And it is shown that the partial field decomposition method based on pressure gradient reference is robust and the decomposed results are better than those based on pressure references.

Amorphous carbon nanodot arrays were successfully prepared through filtered cathodic arc plasma (FCAP) technique, and via a special widen process, the negative effect of the anion impurities distributed in the anodic aluminum oxide (AAO) template was avoided during carbon ions deposition. The morphology of the samples was studied by a field emission scanning electron microscopy (FESEM). The AAO template prepared by multi-steps combining anodization process and pore-widening process has special pore openings. The nanodot arrays are uniformly distributed and in good agreement with the AAO pore arrays. The diameter of the as-prepared nanodot is about 100 nm, and the density was estimated to be 1010 cm-2. Field emission properties of the nanodot arrays were investigated and a low threshold field of 37 V/mm at 10 mA/cm2 was obtained.

We have investigated the surface damage induced by visible laser in LiNbO3:Fe. The laser damage tracks (glide lines and microcracks) and microdomains are produced at +c side of the periphery of light-illuminated regions. These microdomains arise at laser damage tracks and at cylindrical grooves on the surface of sample. We also found that these damage defects in LN:Fe can be decorated by space-charges due to photovoltaic effect and they are directly observable between crossed polarizers. Role of the cavity field, the electrostatic repulsive force at the doma-in boundary and self-enhanced diffraction light induced by physical imperfection on laser-induced surface damage are discussed.

Following our previous work [1], the influence of photo-induced refractive index change on Raman spectra of LiNbO3 crystals doped with 0.07% Fe has been further studied. Anomalous phenomenon appeared in x(zx)z and y(zy)z geometry. This can be explained as the result of interaction between the polarization electrical field of extraordinary phonon and the strong space charge field forming after photo-induced refractive index change in the crystals.