07, 4.56, and 5.70 nm when the molar concentration of NaOH is 0.8, 1.0, and 1.2 M (mol/l), respectively. It is pointed that the particle sizes calculated from the XRD pattern are considerably smaller than those determined from the SEM images. The analysis suggests that the spherical nickel Quisinostat particles may contain a number of ultra small crystals, which agrees with the observation of morphology. Preparation of coiled carbon fibers and corresponding mechanism The CCFs with a constant coil diameter and

coil pitch throughout a piece of the carbon coils could be obtained under the following reaction conditions: temperature of 750°C, time of 2 h, acetylene flow rate at 40 ml/min, hydrogen flow rate at 60 ml/min, and nitrogen flow rate at 100 ml/min. Meanwhile, the GS-1101 cell line liquid thiophene was heated to 40°C using a water bath kettle. The catalytic addictive was

introduced by the acetylene flow into liquid thiophene. From previous study [4–9], the characteristic parameters of helical carbon such as fiber diameter depend on the catalyst properties and reaction condition. To prepare high-purity carbon coils, the Ni nanoparticles prepared Selleckchem NSC 683864 at 70°C, keeping the molar concentration of NaOH solution at 0.8 M, were used as catalyst for CCFs. Figure 5 displays the typical product prepared at 750°C. There are almost all carbon microcoils with regular morphology, and the CCFs are all of double helix, having an average fiber diameter of about 600 nm and coil diameter of 3 μm. Coil gap ranges from zero to several hundred nanometers. It should be noted that the nickel particle size is thinner than those of carbon fiber synthesized in this work. In further experiments, a ceramic plate was placed into the reaction tube instead of graphite substrate, and Ni catalyst was evenly dispersed in the ceramic substrate. Although Levetiracetam other reaction conditions were unchanged, the uniformity of the as-prepared microhelix carbon fibers changes greatly as shown in Figure 6. The distortion of the helical fiber occurred randomly, indicating that the interaction between catalyst and ceramic substrate differs from graphite substrate.

Figure 5 SEM images of regular CMC. SEM images of (a) low magnification and (b) high magnification. The regular CMC was obtained using Ni particles on graphite substrate under the following conditions: reaction temperature of 750°C, N2 at 100 ml/min, H2 at 60 ml/min, C2H2 at 20 ml/min, and bathing temperature of thiophene at 40°C. The regular CMC are made up of double helical fibers A and B. Figure 6 SEM images of irregular CMC. SEM images of (a) low magnification and (b) high magnification. The irregular CMC was obtained using Ni particles on ceramic substrate under the following conditions: reaction temperature of 750°C, N2 at 100 ml/min, H2 at 60 ml/min, C2H2 at 20 ml/min, and bathing temperature of thiophene at 40°C.