Nanostructured Indium Tin Oxides and Other Transparent Conducting Oxides: Characteristics and Applications in the THz Frequency Range

Transparent conductors are essential for optoelectronic components operating in the far-infrared or terahertz (THz) frequency range. Indium tin oxide (ITO), extensively used in the visible, is semi-transparent in the far-infrared frequency range. Other types of bulk transparent conducting oxides (TCOs), such as aluminum-doped zinc oxide (AZO) and aluminum and ytterbium-doped zinc oxide (AYZO), have not yet been explored for THz applications. Recently, biomimic nanomaterials have been shown to exhibit exotic optical properties, e.g., broadband, omnidirectional antireflective properties. Indeed, nanostructured ITO was found to exhibit the above desirable characteristics. In this chapter, we describe the fabrication and characterization of several TCOs, including ITO nanomaterials and several types of bulk TCO thin films, e.g., AZO and AYZO. Performance of THz phase shifters with ITO nanomaterials as transparent electrodes and liquid crystals for functionalities is presented

Supermode-noise-free eighth-order femtosecond soliton from a backward dark-optical-comb-injection mode-locked semiconductor optical amplifier fiber laser,

[[abstract]]A backward dark-optical-comb-injection mode-locked semiconductor optical amplifier fiber laser (SOAFL) with a femtosecond pulse width and an ultrahigh supermode-noise suppressing ratio (SMSR) is primarily demonstrated. The mode-locked SOAFL pulse with a spectral linewidth of 0.45 nm is shortened from 15 to 8.6 ps under chirp compensation in a 420 m long dispersion-compensated fiber, corresponding to a time-bandwidth product of 0.48. The eighth-order soliton is obtained by the nonlinearly soliton's compression of the chirp-compen sated SOAFL pulse in a 112 m long single-mode fiber at an input peak power of 51 W, providing the pulse width, the linewidth, and the nearly transform-limited time-bandwidth product are < 200 fs, 13.8 nm, and 0.34, respectively. The phase noise and integrated timing jitter at an offset frequency below 1 MHz are -105 dBc/Hz and 0.8 ps, respectively. An ultrahigh pulse-compression ratio of 43 and a SMSR of 87 dB for the eighth-order SOAFL soliton are reported.[[fileno]]2010144010129[[department]]物理

Probing the curvature of the Universe from supernova measurement

We study the possibility to probe the spatial geometry of the Universe by supernova measurement of the cubic correction to the luminosity distance. We illustrate with an accelerating universe model with infinite-volume extra dimensions, for which the 1$\sigma$ level supernova results indicate that the Universe is closed.Comment: 8 pages, 3 figures, revised version, accepted for publication in Physics Letters

Effect of thermal exposure on the stress-rupture life and microstructure of a low Re-containing single crystal alloy

AbstractIn this paper, the stress-rupture tests of a low Re-containing single crystal alloy IC21 before and after thermal exposure at 1100°C for various periods of time were conducted under the test condition of 1100°C/137MPa, and the microstructure of the tested specimens was characterized by SEM and TEM. The experimental results showed that the stress rupture life of this alloy was over 150h after the standard heat treatment of 1320°C, 10h/AC+870, 32h/AC, however the stress rupture life decreased with the increase of exposure time due to the microstructure degradation. The TEM analysis revealed that the interface mismatch dislocation networks were well established. It was observed that these mismatch networks could form at 1100°C even after thermal exposure for 1h without the external stress, which is quite different from that in the traditional single crystal superalloys

Coding Properties of Mouse Retinal Ganglion Cells with Dual-Peak Patterns with Respect to Stimulus Intervals

How visual information is encoded in spikes of retinal ganglion cells (RGCs) is essential in visual neuroscience. In the present study, we investigated the coding properties of mouse RGCs with dual-peak patterns with respect to visual stimulus intervals. We first analyzed the response properties, and observed that the latencies and spike counts of the two response peaks in the dual-peak pattern exhibited systematic changes with the preceding light-OFF interval. We then applied linear discriminant analysis (LDA) to assess the relative contributions of response characteristics of both peaks in information coding regarding the preceding stimulus interval. It was found that for each peak, the discrimination results were far better than chance level based on either latency or spike count, and were further improved by using the combination of the two parameters. Furthermore, the best discrimination results were obtained when latencies and spike counts of both peaks were considered in combination. In addition, the correct rate for stimulation discrimination was higher when RGC population activity was considered as compare to single neuron’s activity, and the correct rate was increased with the group size. These results suggest that rate coding, temporal coding, and population coding are all involved in encoding the different stimulus-interval patterns, and the two response peaks in the dual-peak pattern carry complementary information about stimulus interval

Testing Technicolor Models via Top Quark Pair Production in High Energy Photon Collisions

Pseudo-Goldstone boson contributions to $t\bar{t}$ production rates in technicolor models with and without topcolor at the $\sqrt{s}=0.5 and 1.5$ TeV photon colliders and hadron colliders are reviewed. For reasonable ranges of the parameters, the contributions are large enough to be experimentally observable. Models with topcolor, without topcolor and the MSSM with $\tan\beta\geq 1$ can be experimentally distinguished.Comment: Talk given by H.Y. Zhou at the III International Conference on Hyperons,Charm and Beauty Hadrons,Genova,Italy,June 30-July 3 199

Electrochemical Reduction of Uniformly Dispersed Pt and Ag Nanodots on Carbon Fiber Electrodes

Electrochemical characterization of the uniformly dispersed Pt and Ag nanodots synthesized after in situ scalable electron-beam reduction on copper grid and carbon-fiber electrode is demonstrated. By employing plasma pretreatment to produce functional organosilicon micronetworks-based reaction sites on copper grid, the size and standard deviation of the electrochemically reduced metallic nanodots can be strictly confined. When detuning the accelerating voltage of electron-beam from 3 to 120 kV, the reshaped nanodot diameter enlarges from 12.7±0.8 to 18.3±3.6 nm due to the gradual self-aggregation. In comparison with sputtering method, the electroactivity of Pt nanodot covered carbon fiber electrode obtained after electron-beam reduction exhibits a larger electroactive surface (Spt) of 16.56 cm2/mg. The electron-beam reduction provides a better dispersion of the reduced Pt nanodots based catalysts on carbon-fiber electrode, promoting the utilization efficiency of these nanoscale catalyst (defined as the ratio of electroactive to geometric area) from 2.5% to 7%