A simple and fast method to disperse long single-walled carbon nanotubes introducing few defects

A simple and fast dispersion method that incorporates heating is used to disperse long (more than 10 μm) single-walled carbon nanotubes (SWCNTs) with minimal defects. The method enables a dispersed solution of SWCNTs to be produced in less than 10 min in only three steps: (1) addition of the dispersant, (2) heating, and (3) grinding. The dispersion method does not require sonication, which shortens the SWCNTs and can generate surface defects. SWCNT films were prepared from the dispersed solution, and the films exhibited a resistance of 380 Ω/sq at a transparency of 64.8%. This dispersion method can be easily scaled up, making it useful for the preparation of dispersed SWCNTs for commercial and industrial applications.     

Stress intensity factor for transient thermal stresses in a transversely isotropic infinite body with an external circular crack

Summary The present work deals with the transient thermal stress in a transversely isotropic infinite body with an external circular crack. The surface cooling of the crack depends on position and time. Since it it usually very difficult to obtain an analytical solution for the temperature field, a finite difference formulation with respect to a tive variable is introduced. In the first step, applying this method to the general heat conduction equation in an orthotropic body, a very compact difference equation with respect to the spatial variables is obtained. In the second step, this method is applied to the transient thermoelastic problem in a transversely isotropic infinite body with an external circular crack subjected to heat exchange on the crack surface. Thermal stresses are analyzed by means of the transversely isotropic potential functions method.With 7 Figures     

Mutual injection-locking properties of monolithically-integratedsurface-emitting multiple-quantum-well distributed feedback lasers

The mutual injection-locking properties of a coupled pair of multiple-quantum-well distributed-feedback lasers with grating output couplers were investigated experimentally and theoretically. When the mutual injection locking occurred, the output of one laser decreased while that of the other increased. The locking curve was asymmetric, and a stable and an unstable locking region existed. From the theoretical analysis, it was found that the phase delay with which the electric field emitted from each laser to the other laser significantly influences the locking characteristics. The increase and decrease of the locked output power are caused by the phase delay. It is also shown that the laser which receives the larger optical injection behaves like a slave laser and the laser which has less optical injection behaves like a master laser, and the shape of the locking curve is determined by the balance between the α parameter and the thermal resistance     

Dynamic spectral width of an InGaAsP/InP electroabsorption light modulator under high-frequency large-signal modulation

The first measurements of dynamic spectra of an InGaAsP/InP electroabsorption light modulator under high-frequency large-signal modulation are reported. A spectral broadening factor ? was determined from the relative sideband strength to the carrier, and it decreased with increasing operating electric field in the modulator. The estimated ?-value for full modulation was |?| = 2.3, which can be reduced by designing a modulator to give a more effective change of electro-absorption.     

A 144-Mb, eight-level NAND flash memory with optimized pulsewidthprogramming

We report a fast-programming, compact sense and latch (SL) circuit to realize an eight-level NAND flash memory. Fast programming is achieved by supplying optimized voltage and pulsewidth to the bit lines, according to the programming data. As a result, all data programming is completed almost simultaneously, and 0.67-MB/s program throughput, which is 1.7 times faster than conventional program throughput, is achieved. The compact layout of the SL circuit is made possible by four 3-bit latches sharing one unit of the read/verify control circuit. Using these techniques, we fabricated a 144-Mb, eight-level NAND flash memory using a 0.35-μm CMOS process, resulting in a 104.2-mm² die size and a 1.05-μm² effective cell size     

Correlation between the compositional and pasting properties of various potato starches

Multiple linear regression equations were used to develop the correlation between the compositional and rapid visco-analysis (RVA) pasting properties of various potato starches. The amylose of potato starches had a negative correlation with the peak viscosity (PV) and breakdown (BD) and a positive correlation with the setback viscosity (SV) and peak viscosity temperature (PVT). By contrast, phosphorus had a positive correlation with PV, BD, and SV and a negative correlation with PVT. In addition, the median granule size had a positive correlation with PV and BD. By contrast, a negative correlation of the median granule size was observed with SV and PVT. The correlation coefficients of amylose–phosphorus, amylose–granule size, and phosphorus–granule size interactions indicated that amylose had more influence than had phosphorus or had the median granule size on PV and BD. Furthermore, amylose had a greater influence than had the granule size on SV and PVT. Similarly, amylose had more influence than had phosphorus or had the median granule size on PVT. However, the correlation developed in this study was useful for predicting the influence of a specific component and the compositional interaction on the RVA pasting properties.     

Polarisation-maintaining fibre couplers with low excess loss

Polarisation-maintaining fused fibre couplers with excess loss of less than 0.1 dB have been fabricated by using polarisation-maintaining and absorption-reducing (PANDA) fibres with matched-index stress-applying parts. The couplers show polarisation crosstalk of less than ?30 dB.