Bar Arrays

Lieber has reviewed the work done in his laboratory to synthesize and determine the properties of NWs and nanotubes. He used Au or Fe catalyst nanoclusters to serve as the nuclei for NWs of Si and GeAs with 10 nm diameters and lengths of hundreds of nm. By choosing specific conditions, Lieber was able to control both the length and the diameter of the single crystal semiconductor NW. Silicon NWs doped with B or P were used as building 

Heath reported the synthesis of silicon NWs by chemical vapor deposition using SiHt as the Si source and An or Zn nanoparticles as the catalytic seeds at 440°C. The wires produced varied in diameter from 14 to 35 nm and were grown on the surface of silicon wafers. After growth, isolated NWs were mechanically transferred to wafers and A1 contact electrodes were put down by standard e-beam lithography and e-beam evaporation such that each end of a wire was connected to a metallic contact. In some cases a gate electrode was positioned at the middle of the wire. Tapping-mode atomic force microscopy (AFM) indicated the wire in this case was 15 nm in diameter. 

Heath found that annealing the Zi-Si wires at 550° C produced increased conductance attributed to better electrode/nanowire contacts. Annealing Au-Si wires at 750° C for 30 min increased current about 10 , an effect attributed to doping of the Si with Au, and lower contact resistance between the wire and Ti/Au electrodes. 

Much research has been done to determine the efficacy of SWNTs as NWs in molecular computers. One problem with SWNTs is their lack of solubility in common organic solvents. In their synthesized state, individual SWNTs form ropes from which it is difficult to isolate individual tubes. In our laboratory some solubility of the tubes was seen in 1,2-dichlorobenzene. An obvious route to higher solubility is to functionalize SWNTs by attachment of soluble groups through covalent bonding. Margrave and Smalley found that fluorinated SWNTs were soluble in alcohols while Haddon and Smalley were able to dissolve SWNTs by ionic functionalization of the carboxylic acid groups present in purified tubes. 

R = halogen, CO2CH3, NO2, fert-butyl, COOH, in addition to O2N 

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Figure 7.21. SEM image of cross-bar array of aligned PVP nanofibers. (Li, D., et. al.. Advanced Materials, 16, 361-366, 2004.)...

An important development in the 1980s was the multiple stripe laser, capable of emission of high output powers. A number of stripes are placed on a bar perhaps 1 cm wide the output of the different stripes is coupled so that the device may be regarded as a single laser. Bars having continuous output up to 20 W are available in the aluminum gallium arsenide system. A number of bars may then be stacked to form two-dimensional arrays with high values of output power. 

Van Wingerden and Zeeuwen (1983) demonstrated increases in flame speeds of methane, propane, ethylene, and acetylene by deploying an array of cylindrical obstacles between two plates (Table 4.3). They showed that laminar flame speed can be used as a scaling parameter for reactivity. Van Wingerden (1984) further investigated the effect of pipe-rack obstacle arrays between two plates. Ignition of an ethylene-air mixture at one edge of the apparatus resulted in a flame speed of 420 m/s and a maximum pressure of 0.7 bar. 

Less important oxides are Ag203, obtained impure by extended anodic oxidation of silver, and Ag30, obtained hydrothermally from Ag/AgO at 80°C, 4000 bar, which is a metallic conductor with the anti-BiI3 structure containing an hep array of silvers with oxide ions occupying 2/3 of the octahedral holes [32]. 

Fig. 2.69a,b Coefficient of performance for aluminum plate fin array in forced convection (a) maximum heat transfer design, and (b) least material design. Reprinted from Bar-Cohen et al. (2006) with permission... 

Chaudhari AM, Woudenberg TM, Albin M, Goodson KE (1998) Transient liquid crystal thermometry of microfabricated PCR vessel arrays. J Microelectromech Sys 7 345-355 Cheng P, Wu WY (2006) Mesoscale and microscale phase heat transfer. In Greene G, Cho Y, Hartnett J, Bar-Cohen A (eds) Advances in heat transfer, vol 39. Elsevier, Amsterdam Choi SB, Barron RF, Warrington RQ (1991) Fluid flow and heat transfer in micro- tubes. ASME DSC 40 89-93... 

PI. 2.1 A Cellular morphology of ncuroepithelium. Microvilli multiple array at apex of dendrite from an isolated Frog VNOR cell, scale bar = 1 pm SEM (from Trotier el aL, 1994). 

Fig. 8.5 SEM images of (A) close packed array of latex beads (scale bar= 1 tm) and (B) macroporous aminopropyl-functionalized magnesium phyllosilicate monolith obtained after infiltration and extraction of colloidal template (scale bar= 1 pm).

Figure 10.17. (a) Schematic diagram of the nanowire dye-sensitized solar cell. Light is incident through the bottom electrode, (b) SEM cross section of a solution-fabricated ZnO nanowire array on fluorine-doped tin oxide. The wires are in direct contact with the substrate. Scale bar, 5 pm. Reproduced from Ref. 41, Copyright 2005, with permission from the Nature Publishing Group. 

Fig. 4.3 SEM images of the long range packing assembly of composite colloidal crystal array films assembled on different substrates (a) polycarbonate sheet, (b) Teflon sheet, and (c) Teflon film. The submicron particles were composed of 326 nm diameter polystyrene beads coated with a 20 nm thick Si02 shell. Scale bars in (a c) are 3.00, 3.00, and 2.72 pm, respectively...

Next we consider the compact star in the low mass X-ray binary 4U 1728-34. In a very recent paper Shaposhnikov et al. (2003) (hereafter STH) have analyzed a set of 26 Type-I X-ray bursts for this source. The data were collected by the Proportional Counter Array on board of the Rossi X-ray Timing Explorer (RXTE) satellite. For the interpretation of these observational data Shaposhnikov et al. 2003 used a model of the X-ray burst spectral formation developed by Titarchuk (1994) and Shaposhnikov Titarchuk (2002). Within this model, STH were able to extract very stringent constrain on the radius and the mass of the compact star in this bursting source. The radius and mass for 4U 1728-34, extracted by STH for different best-fits of the burst data, are depicted in Fig. 6 by the filled squares. Each of the four MR points is relative to a different value of the distance to the source (d = 4.0, 4.25, 4.50, 4.75 kpc, for the fit which produces the smallest values of the mass, up to the one which gives the largest mass). The error bars on each point represent the error contour for 90% confidence level. It has been pointed out (Bombaci 2003) that the semi-empirical MR relation for the compact star in 4U 1728-34 obtained by STH is not compatible with models pure hadronic stars, while it is consistent with strange stars or hybrid stars. 

Numerous CE separations have been published for synthetic colours, sweeteners and preservatives (Frazier et al., 2000a Sadecka and Polonsky, 2000 Frazier et al., 2000b). A rapid CZE separation with diode array detection for six common synthetic food dyes in beverages, jellies and symps was described by Perez-Urquiza and Beltran (2000). Kuo et al. (1998) separated eight colours within 10 minutes using a pH 9.5 borax-NaOH buffer containing 5 mM /3-cyclodextrin. This latter method was suitable for separation of synthetic food colours in ice-cream bars and fmit soda drinks with very limited sample preparation. However the procedure was not validated for quantitative analysis. A review of natural colours and pigments analysis was made by Watanabe and Terabe (2000). Da Costa et al. (2000) reviewed the analysis of anthocyanin colours by CE and HPLC but concluded that the latter technique is more robust and applicable to complex sample types. Caramel type IV in soft drinks was identified and quantified by CE (Royle et al., 1998). 

Fig. 12.3 Fabrication of the nanocomposite paper units for battery, (a) Schematic of the battery assembled by using nanocomposite film units. The nanocomposite unit comprises LiPF6 electrolyte and multiwalled carbon nanotube (MWNT) embedded inside cellulose paper. A thin extra layer of cellulose covers the top of the MWNT array. Ti/Au thin film deposited on the exposed MWNT acts as a current collector. In the battery, a thin Li electrode film is added onto the nanocomposite, (b) Cross-sectional SEM image of the nanocomposite paper showing MWNT protruding from the cel-lulose-RTIL ([bmlm] [Cl]) thin films (scale bar, 2pm). The schematic displays the partial exposure of MWNT. A supercapacitor is prepared by putting two sheets of nanocomposite paper together at the cellulose exposed side and using the MWNTs on the external surfaces as electrodes, (c) Photographs of the nanocomposite units demonstrating mechanical flexibility. Flat sheet (top), partially rolled (middle), and completely rolled up inside a capillary (bottom) are shown (See Color Plates)...

Figure 5.21 CuUPDonaSAM patterned by an STM tip. (a) Native BP2 SAM on Au(l 1 1) and (b) array of nine patches generated by tip induced modification. A patch was generated by applying a voltage pulse of 3.5 V for 50 ms. Modification and imaging was done in air. (c, d) In-situ ECSTM images of Cu UPD at different stages, (c) was recorded immediately after start of UPD and (d) after 12 min. Scale bars are 20 nm [230].

Fig. 4. Images of unfixed and unstained chromatin in a frozen and hydrated state. All samples shown contain linker histone H5. (A) Soluble chromatin prepared from chicken erythrocyte nuclei. Arrow indicates a nucleosome with a linker histone stem conformation. (B-E) Chromatin reconstituted onto an array of the 5S rDNA nucleosome positioning sequence. En face views (B-D) of nucleosomes show the linker DNA entering and exiting the nucleosome tangentially, before interacting and remaining associated for 3-5 nm before separating (arrows). An edge-on view (E) shows the two gyres of DNA (arrow heads) and the apposed linker DNA (arrow) (from Ref. [30]). Scale bar 20 nm (A) and 10 nm (B-E).

Fig. 7. GFP-GR bound to the MMTV array was analyzed by fluorescence recovery after photobleaching (FRAP). The bleached region is indicated in the image of the pre-bleached nucleus (A). The pre-bleach array is shown in (B), the post-bleach image (C), and at 4.1 s (D) and 11.6 s (E) post-bleach. This analysis, along with Fluorescence Loss in Photobleaching (FLIP) experiments, show that GFP-GR undergoes rapid exchange with the array (from Ref. [58]). Scale bar 5 pm.

Fig. 8. Time lapse images of two MMTV arrays visualized with GFP-GR. Time in minutes after addition of 100 nM dexamethasone is indicated. Some arrays become very extended (3-10 pm, B), whereas some cells exhibit a less extended array (< 3 pm, A) (from Ref [68]). Scale bar 1 pm.

If the chemistry is amenable, it is possible to synthesize a large number of small samples of polymers by simply mixing the ingredients in either small vials or multiwell plates. For example, Brocchini et al. prepared a library of 112 polymers by mixing the monomers in individual vials which were placed in a water bath [22]. Akinc et al. synthesized a library of 24 unique poly(j3-amino esters) via the conjugate addition of acrylates and amines by mixing the monomers in sample vials fitted with stir bars [23]. To speed up this process, a liquid handling robot can be used to dispense the raw materials into an array of vials [24]. 

Figure 27-7 Native nuclear lamina of Xenopus oocytes. Freeze-dried metal-shadowed nuclear envelope extracted with Triton X-100, revealing the nuclear lamina meshwork partially covered with arrays of nuclear pore complexes. Inset, relatively well-preserved area of the meshwork of nearly orthogonal filaments from which pore complexes have been mechanically removed. Bar, 1 pm. From Aebi et al.121...

Fig. 5. Combined in.vi hybridization and immunocytochcmistry. Part of the nucleus of an erythroid precursor ceil infected with parvovirus B19. There is colabeling of the viral DNA 10-nm gold) using in situ hybridization and the B19 capside protein (5-nm gold) by immunocytochemistty over an intranuclear crystalline array (Cr) of viral particles see ref. 7 for details). Nu, nucleus Ch, heterochromatin. Bar is 0.1 pm.

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