Deeply penetrating photoacoustic tomography in biological tissues enhanced with an optical contrast agent

Photoacoustic tomography (PAT) in a circular scanning configuration was developed to image deeply embedded optical heterogeneity in biological tissues. While the optical penetration was maximized with near-infrared laser pulses of 800-nm wavelength, the optical contrast was enhanced by Indocyanine Green (ICG) dye whose absorption peak matched the laser wavelength. This optimized PAT was able to image objects embedded at depths of as much as 5.2 cm, 6.2 times the 1/e optical penetration depth, in chicken breast muscle at a resolution of <780 microm and a sensitivity of <7 pmol of ICG in blood. The resolution was found to deteriorate slowly with increasing imaging depth. The effects of detection bandwidth on the quality of images acquired simultaneously by four different ultrasonic transducers are described.     

Capillary Coated with Layer-by-Layer Assembly of γ-Zirconium Phosphate/ Lysozyme Nanocomposite Film for Open Tubular Capillary Electrochromatography Chiral Separation

A new capillary coating of alternate -zirconium phosphate lysozyme fabricated for open-tubular electrochromatography enantioseparation. The chiral compounds D, L-tryptophan tested were enantiomerically resolved. The influences brought by experimental parameters, such as organic modifier, temperature, applied voltage and pH of running buffer on the performance of the column, were investigated.     

Calculation of the Electron Efficiency for a Two-Cavity Gyroklystron Amplifier by Using a Self-Consistent Code

The beam-wave interaction in a Ka-band, two-cavity fundamental gyroklystron amplifier is studied by using a self-consistent nonlinear simulation code. The electron efficiency for this gyroklystron amplifier is calculated, and the effect of various parameters, such as beam voltage, beam current, electron guiding center radius, velocity pitch ratio and drift tube length on the electron efficiency is discussed in detail.     

A nanoscale dendrimer-based Fe24 cluster: synthesis and molecular self-assembly

We report the synthesis, characterisation and self-assembly of a nanoscopic Fe24 cluster using an organic dendrimer as a molecular substrate for building up well-defined molecular nanostructures.     

Growth of aligned carbon nanofibres over large areas using colloidal catalysts at low temperatures

Highly purified cobalt colloids have been employed as a catalyst to grow aligned carbon nanofibres at temperatures as low as 300 degree C by dc plasma enhanced chemical vapour deposition over large areas.     

衬底温度对MOCVD法沉积ZnO透明导电薄膜的影响

研究了衬底温度对MOCVD技术制备的ZnO薄膜的微观结构和光电特性影响. XRD和SEM的研究结果表明，衬底温度对ZnO薄膜的微观结构有显著影响，明显的形貌转变温度大约发生在175℃，低于175℃，薄膜呈镜面结构，晶粒为球状，高于177℃的较高温度范围，薄膜从“类金字塔”状的绒面结构演化为“岩石”状显微组织；随着温度增加，薄膜的晶粒尺寸明显增大.绒面结构的未掺杂ZnO薄膜具有17.96 cm²/V·s的高迁移率和3.28×10^-2 Ω·cm的低电阻率，对ZnO薄膜的进一步掺杂和结构优化有望应用于Si薄膜太阳电池的前电极. 关键词： MOCVD ZnO薄膜 透明导电氧化物 太阳电池     

试论在物理实验教学中施行创新教育

物理实验作为物理教学的基本手段，有其特殊的教学功能，不仅能够为学生提供学习的感性材料，验证物理定律，而且能够提供科学的思维方法，加深学生对基本知识的认识程度，激发他们的求知欲，培养探索能力．而众多的物理概念、规律正是通过观察和实验再认真地加以思索和总结得到的．     

Discussion again of the magnetic and transport property of Ag-doped LaMnO3

Samples La_1−aAg_aMnO₃ (0.05?a?0.50) were sol–gel fabricated. A part of Ag was found to dissociate and run off the samples in sintering process when sintering temperature exceeds 700 °C, resulting in a composite of La_1−xAg_xMnO₃ and MnO₂/Mn₂O₃. The magnetic and transport properties of the composite have been studied. The sample with the nominal composition La_0.7Ag_0.3MnO₃ was found to show the greatest magnetoresistance in the sample group. Detailed analysis on average Mn valence reveals a composite of (La_0.985Ag_0.015MnO₃)_0.776[(MnO₂)_0.590(Mn₂O₃)_0.410]_0.224. Its MR ratio at room temperature exceeds 24% under a field of 1.8 T. A conductivity leap has been observed around a=0.30. It suggests a kind of field-induced fluctuation in percolation in the samples investigated.     

2277-W continuous-wave diode-pumped heat capacity laser

A high power continuous-wave (CW) diode-pumped Nd:YAG laser operated in heat capacity mode is demonstrated by use of two identical highly efficient diode-pumped laser heads placed in a plane-plane resonator. The laser heads are uniformly pumped with a five-fold symmetrical side-pumping configuration,and each head is able to output maximum output power of 2200 W at 808 nm. Under a total pump power of 4290 W, the output power of the laser at 1064 nm is up to 2277 W, corresponding to an optical-to-optical efficiency of 53.1%.