黄孢原毛平革菌210对稀土离子的吸附作用研究

通过电感耦合等离子体发射光谱(ICP-OES)、扫描电镜等手段研究了黄孢原毛平革菌210对镧离子(La3+)及其他稀土离子的吸附能力。结果表明,在pH=7,La3+浓度为40 mg.L-1,菌体投加量60 mg.L-1(以干重计),吸附时间120 min时,黄孢原毛平革菌210的吸附量最大,达141.5±4.72 mg.g-1。经盐酸预处理的菌体吸附能力有所提高,其他预处理则使菌体吸附能力下降。解吸剂柠檬酸和EDTA都能较好地解吸La3+。黄孢原毛平革菌210对单一稀土离子的吸附能力差异较大。在15种混合稀土离子溶液中,对Lu3+,Sm3+,Eu3+的吸附量较高,对混合稀土离子具有一定的富集、分离作用。扫描电镜发现La3+可能主要以盐的形式沉积在菌体表面上。     

GHz microwave properties of melt spun Fe-Si alloys

The structural and microwave properties of melt spun Fe_100−xSi_x (x = 10, 20, 30) nanocomposites were investigated. The phases varied with Si content in FeSi alloys. It is found that the Fe₃Si and FeSi phases could be obtained with Si content up to 20 at.%. The X-ray absorption fine structure (XAFS) spectra of Fe K-edges show that the local structures around Fe atoms in melt spun Fe-Si alloys become more disordered with increasing Si content when compared with that of α-Fe. The complex permittivity-frequency and permeability-frequency properties were determined in the microwave frequency regime of 2-18 GHz by vector network analysis. It is found that flake-like FeSi powder composite has the largest values of μ′ and μ″ at 2 GHz. The reflection loss shifts to the higher frequency with the Si content increasing for melt spun FeSi alloys. A minimum reflection loss of −16.5 dB is obtained at 13.9 GHz for composition Fe₇₀Si₃₀ with the thickness of 1.5 mm. However, for composition Fe₇₀Si₃₀, the minimum reflection loss shifts to lower frequency and larger value with the thickness increasing. The results suggest a new design for microwave absorbers based on electromagnetic wave-absorbing materials.     

光电子成像研究AgOCH3-和Ag-(CH3OH)x (x=1, 2)

用光电子成像技术和从头算法研究Ag^-(CH₃OH)_x (x=1, 2)和AgOCH₃^-. 从AgOCH₃^-振动分辨的光电子谱得 到AgOCH₃^-的绝热和垂直电离能分别为1.29(2)和1.34(2) eV. Ag^-(CH₃OH)_{1,2相似文献}   

Projective synchronization of two coupled excitable spiral waves

Interaction of two identical excitable spiral waves in a bilayer system is studied. We find that the two spiral waves can be completely synchronized if the coupling strength is sufficiently large. Prior to the complete synchronization, we find a new type of weak synchronization between the two coupled systems, i.e., the spiral wave of the driven system has the same geometric shape as the spiral wave of the driving system but with a much lower amplitude. This general behavior, called projective synchronization of two spiral waves, is similar to projective synchronization of two coupled nonlinear oscillators, which has been extensively studied before. The underlying mechanism is uncovered by the study of pulse collision in one-dimensional systems.     

Positive solutions of the system for nth-order singular nonlocal boundary value problems

The paper deals with the existence and multiplicity of positive solutions to systems of nth-order singular nonlocal boundary value problems. The main tool used in the proof is fixed point index theory in cone. Some limit type conditions for ensuring the existence of positive solutions are given.     

Study of acoustic field modulation in the regenerator by double loudspeakers method

A model to modulate acoustic field in a regenerator of a thermoacoustic system by the double loudspeakers method is presented in this paper. The equations are derived for acoustic field modulation. They represent the relations among acoustic field (complex pressure p(0), complex velocity u(0), and acoustic impedance Z(0)), driving parameters of loudspeakers (voltage amplitude and its phase difference), and operating parameters involved in a matrix H (frequency, temperature of regenerator). The range of acoustic field is adjustable and limited by the maximal driving voltages of loudspeakers according to driving parameters. The range is simulated and analyzed in the amplitude-phase and complex coordinate planes for a given or variable H. The simulated results indicate that the range has its intrinsic characteristics. The expected acoustic field in a regenerator can be obtained feasibly by the modulation.     

Effects of nanostructure on optoelectronic properties of β phase polyoctylfluorene thin film

β phase polyoctylfluorene thin films were obtained by exposure to toluene vapor for various annealing times or dipping into a THF/methanol mixture. The photoluminescence and electroluminescence of PFO thin films decrease with increasing annealing time. Grazing incident X-ray diffraction of the thin films indicates that more and larger β phase crystallites will be generated in thin film exposed for longer time, which will lead to more defects that reduce photoluminescence and electroluminescence. By analyzing the mechanism of formation of β phase, we assume that the defects mainly come from the formation of out-of-plane crystalline structure. The assumption is confirmed by higher photoluminescence of β phase polyoctylfluorene thin film achieved by dipping into a THF/methanol mixture that has less out-of-plane crystalline structure.     

A full-duplex radio-over-fiber system based on dual quadrupling-frequency

We proposed and simulatedly demonstrated a novel full-duplex radio-over-fiber system using an external modulator and an optical interleaver to generate dual quadrupling-frequency optical millimeter waves for carrying two base station downstream data and wavelength reuse for uplink connection. The simulation results reveal that the power penalties for the downstream and upstream signals of both base stations are less than 0.8 dB. In this new scheme, the configuration of the both base stations is simplified further because there is no additional laser at two base stations. The frequency of local oscillator signal is reduced due to frequency quadrupling. The cost of the new system is largely reduced.     

Surface plasmon tunneling through a touching gold nanocylinder array on a thin gold film

The optical property of a structure composed of a touching gold nanocylinder array on a thin gold film is investigated using finite-difference time-domain (FDTD) method. It is discovered that the transmission behavior can be tuned by tuning the geometry of the structure. As the film thickness increases, the transmission mode associated with the localized surface plasmon resonance blue shifts accompanied with a decrease of magnitude and full width at half maximum, and a second transmission appear due to the interaction of the plasmons on the cylinder with their images induced on the film. The localized waveguide resonance diminishes but the second resonance peak is intensified and broadened noticeably with the separation of the cylinder array and film increase. The cylinder radius size influences the localized surface plasmon resonance mode obviously. These results may be helpful for the design of a novel optical device.     

Generation of atomic entangled states in a bi-mode cavity via adiabatic passage

We propose schemes to prepare atomic entangled states in a bi-mode cavity via stimulated Raman adiabatic passage (STIRAP) and fractional stimulated Raman adiabatic passage (f-STIRAP) techniques. Our scheme should be realizable in the near future because of the existence of all experimental ingredients. Our numerical simulation shows we can entangle the atoms with high fidelities by choosing proper laser pulses.