Influence of heating and laser irradiation on the Raman D band in single-wall carbon nanotubes

Fine structure of the Raman D band in single-wall carbon nanotubes (SWNTs) was investigated by heating and laser irradiation. It is shown that the D band is composed of three components at ～ 1313, 1340, and 1355 cm^? 1, denoted by D₁, D₂, and D₃, respectively. The D₁ and D₂ intensities significantly increase with laser irradiation in air and vacuum, respectively. The D₃ intensity drastically increases with heating in air. From these results, it is suggested that the fine structure of the D band is attributed to different kinds of defects introduced in SWNTs.     

Motion of 2D Buoyant Clouds Downslope

The motion of conservative 2D thermals on beds with slope angles θ ranging from 5 to 90° is investigated theoretically and experimentally. Using a large number of experimental data, important flow characteristics, including the shape factors, spatial growth rate, propagation speed, and entrainment coefficient, are quantified as functions of bottom slope angles. A thermal model, which includes a resistance term, is developed. It is found semiempirically that resistance coefficients Cd are almost independent of θ and the values of Cd are in the range of 0.4–0.6. Capability of the model is demonstrated by comparing numerical results with theoretical as well as experimental results.     

The soluble N-ethylmaleimide-sensitive factor attached protein receptor complex in growth cones: molecular aspects of the axon terminal development

Soluble N-ethylmaleimide-sensitive factor attached protein (SNAP) receptor (SNARE) mechanisms are thought to be involved in two important processes in axonal growth cones: (1) membrane expansion for axonal growth and (2) vesicular membrane fusion for mature synaptic transmission. We investigated the localization and interactions among the proteins involved in SNARE complex formation in isolated growth cone particles (GCP) from forebrain. We demonstrated that the SNARE complex is present in GCPs morphologically without synaptic vesicles (SVs) and associated with growth cone vesicles. However, the apparently SV-free GCP was lacking in the regulatory mechanisms inhibiting SNARE complex formation proposed in SV fusion, i.e., the association of synaptotagmin with the SNARE complex, and vesicle-associated membrane protein (VAMP)-synaptophysin complex formation. The core components of the SNARE complex (syntaxin, SNAP-25, and VAMP) accumulated for several days before postnatal day 7, when SVs first appeared, and preceded the accumulation of marker proteins such as synaptophysin, SV2, and V-ATPase. Our present results suggest that the SNARE mechanism for vesicular transmitter release is not fully functional in growth cones before the appearance of SVs, but the SNARE mechanism is working for membrane expansion in growth cones, which supports our recent report. We concluded that the regulation of the SNARE complex in growth cones is different from that in mature presynaptic terminals and that this switching may be one of the key steps in development from the growth cone to the presynaptic terminal.     

微导通孔的电镀填孔技术

本文主介绍了电镀填孔技术,并探讨了DC和PPR电镀填孔技术的优缺点和影响填孔效果的相关因素。     

A comparison of the hydrolysis of sweet potato starch with β-amylase and infrared radiation allows prediction of reducing sugar production

The apparent reaction rate constants (k) of the reaction that generates reducing sugar (presented as mg maltose equivalents) from raw sweet potato starch by using β‐amylase were determined by varying enzyme concentration, starch concentration and pH. The Arrhenius plot of the k‐value reached a peak at approximately 86 °C; the activation energy and frequency factor were also determined. Moreover, the amount of reducing sugar produced in sweet potato heated by infrared irradiation was estimated by using the values of k and the kinetic parameters. The calculated amounts of reducing sugar produced generally agreed with the experimental values. These results indicate that the amount of reducing sugar produced in heat‐treated sweet potato can be predicted by the methodology described in this study.     

Effects of photoirradiation in UV and VUV regions during plasma exposure to polymers

Interactions between photons irradiated from Ar-O₂ mixture plasmas and polymer surfaces were investigated on the basis of depth analyses of chemical bonding states in the nano-surface layer of polyethylene terephthalate (PET) films via hard X-ray photoelectron spectroscopy (HXPES) and conventional X-ray photoelectron spectroscopy (XPS). The PET films were exposed to photons from the Ar-O₂ mixture plasmas by covering the PET samples with MgF₂ and quartz windows as optical filters for evaluation of photoirradiation effects in ultraviolet (UV) and vacuum ultraviolet (VUV) regions. The HXPES results indicated that the degradation of the chemical bonding states due to photoirradiation in regions was insignificant in deeper regions up to about 50 nm from the surface. Whereas, conventional XPS analysis showed that CO bond, OCO bond and CO bond increased after photoirradiation in UV and VUV regions. These results suggest that the increase in oxygen functionalities (CO bond, OCO bond and CO bond) may be attributed to chemical reactions and/or terminations of scissed bonds via photodecompositions of the polymer with oxygen and/or OH species (oxygen molecules and radicals during plasma exposure and/or oxygen molecules and moisture after taking the PET samples out of the plasma reactor to the ambient air) in the vicinity of the sample surface.     

Seismic Earth Pressure Exerted on Retaining Walls Under a Large Seismic Load

In recent years, serious damage has been done to retaining structures because of large earthquakes. In order to establish practical methods for evaluating the seismic earth pressure, which is one of the important external forces acting on retaining structures during large earthquakes, a series of shaking table tests was conducted on retaining wall (RW) models. The experiments revealed that the seismic active earth pressure was considerably smaller than that obtained by the Mononobe-Okabe theory, particularly under a large seismic load. Furthermore, it was demonstrated that the seismic earth pressure had an upper limit, which was determined by the force equilibrium of the soil wedge at the critical state when the RW lost its stability. On the basis of the test results, a new method to evaluate the seismic earth pressure for practical designs under a large seismic load has been suggested. This proposed method provides a reasonable earth pressure as well as an angle of failure plane, those of which depend on the seismic stability of the retaining wall. It has been confirmed that earth pressure obtained by the proposed method agrees well with the measured seismic earth pressure exerted on several retaining walls with different degrees of stability.