Laser Technology in Micromanufacturing
Department of Mechatronics, Gwangju Institute of Science and Technology, Republic of South Korea Laser technologies are utilised in various fields like micromanufacturing, instrumentation, imaging, medicine, communications, etc. Although each of these fields is as important as others, we will limit our discussion to the application of laser technologies for manufacturing only. Application of lasers to micromanufacturing has several advantages such as noncontact processing, capability of remote...
Structure of Carbon Nanotubes CNTs
CNTs are surely the most important nanostructures both from a fundamental point of view and for future applications. Initially, CNTs were simply be sorted by single-walled carbon nanotube SWCNT and multi-walled carbon nanotube MWCNT Fig. 11.2 . Paid most attention by scientists and engineers, different types of CNTs have been synthesised via various processes. Y-shaped junctions and rings composed of single wall CNTs are proposed as possible nanosized electronic devices exhibiting quantum...
Growing Interest in Carbon Nanotube
The report of Kroto et al. in 1985 on the discovery of bulkyball, fullerene C60 molecule led into a new beginning in carbon materials and a huge interest in their sciences. Sumio Iijima of NEC Laboratory in Tsukuba observed MWNTs with high-resolution transmission electron microscopy TEM in 1991, and two years later he observed SWNTs. While for the first time, researchers at the William Rice University synthesised bundles of SWNTs in 1996, and most recently, in 2003 Fakhru'l-Razi, Iyuke and...
Subtractive Pattern Transfer
Reactive ion etching RIE has been used for subtractive pattern transfer into silicon substrates, where the resist acts as an etch mask. Etching is particularly challenging with ultra-thin photoresist, since the gases used to etch the silicon also etch the resist. Using cryogenic temperatures suppresses the resist etching and a successful dry etching process has been developed as detailed in Fig. 17.8. A short SF6 plasma etch was carried out at 173 K to transfer the resist pattern 120 nm deep...
Additive Pattern Transfer
Additive pattern transfer involves the addition of metal films through a resist mask onto a substrate the photoresist layer is then removed or lifted-off. Successful additive pattern transfer is not possible with ultra-thin resist. To achieve lift-off the resist should have a slightly undercut profile, and the resist thickness should be significantly greater than the metal being deposited. A trilayer scheme has been developed which improves the resist profile for lift off processes. The...
Driving Principles for Actuation
The driving principles used to drive various types of micromachined MEMS systems are primarily four types, namely, Fig. 2.1. Microelectromechanical systems Each driving principle has specific advantages and disadvantages with respect to deflection range, required force, environmental durability, and most importantly the response time. Furthermore, the required power supply mainly depends on the driving principles involved Table 2.1 . Table 2.1 typical power requirements for respective driving...
Diaminooctanederivatised C60 Films
Pristine C60 and its films are soluble in toluene at room temperature, whereas the samples both crystalline C60 and fullerene films on silicon after reacting with 1,8-diaminooctane become poorly soluble. AFM studies Fig. 20.4 show clearly large differences in the film morphology before and after the diamine treatment. The pristine films are typically composed of well-shaped C60 clusters, of ca. 50 nm average diameter Fig. 20.4 a . The clusters become diffuse after the modification, and the...
Direct Amidation of Carboxylic Functionalities on Oxidised SWNT Tips
As it was mentioned above, the most extensively explored approach to the synthesis of amide derivatives between carboxylic groups on oxidised CNT tips and long-chain amines relies upon preliminary chemical activation of the carboxylic groups with thionyl chloride or carbodiimides in an organic solvent medium, followed by the addition of amine reagent Ausman et al. 2000 Bahr and Tour, 2002 Basiuk and Basiuk 2004 Hamon et al. 1999 Hirsch 2002 Sun et al. 2002 Wong et al. 1998a,b . In our approach...
Structure of Fullerenes
Fullerenes are another exotic nanostructure of carbon. Initially, considering C60, fullerenes were usually thought to have a shape of regular sphere. Along with the in-depth research on fullerenes, other types have been discovered, such as cone shape and tube shape. Here the structures of some new fullerenes will be introduced. A recent research has constructed 27 isomers for the C48 cage and these are shown in Fig. 11.12 Wu et al. 2004 . It is found that the most stable C48 structure has the...
Synthesis
In this section, different techniques for the synthesis of various carbon nanostructures are summarized. Firstly, growth mechanism is explained briefly. Then the detailed introduction to each synthesis method of nanotubes, fullerenes, nanoballs and nanofibers will be shown. The most results summarized are almost appeared in the literature in the last 5 years, standing for the update proceeding of the synthesis of carbon nanostructures. They are many known ways to prepare carbon nanotubes....
Measurement and Readout Technique
The deflection of the cantilever is measured with various systems. The most common sensors that are used to sense cantilever bending include optical levers, interferometry and a piezoresistive element. Resonance frequencies are mainly measured with optical components that use an external oscillator. Alternatively charge coupled devices CCDs that record through an optical microscope are used to detect a self-oscillating cantilever Davis et al. 2000 . Recently, we have demonstrated self-exciting...
References Pjf
Ausman KD, Piner R, Lourie O, Ruoff RC, Korobov M 2000 Organic solvent dispersions of single-walled carbon nanotubes Toward solutions of pristine nanotubes, J Phys Chem B 104 8911 Bahr JL, Tour JM 2002 Covalent chemistry of single-wall carbon nanotubes, J Mater Chem 12 1952 Basiuk VA 2002 Reactivity of carboxylic groups on armchair and zigzag carbon nanotube tips A theoretical study of esterification with methanol, Nano Lett. 2 835 Basiuk VA 2003 ONIOM studies of chemical reactions on carbon...
Conclusions Dtm
The treatment of C60 fullerene films on silicon substrates with 1,8-octanediamine vapour at ca. 120 C reduces dramatically fullerene solubility in toluene, indicating the transformation of C60 into a different solid phase of polymeric nature. Compared to the spectra of pristine C60, IR spectra of the transformed phase exhibit new lines along with a decrease or total disappearance of some IR-active modes typical for C60, due to the lowering icosahedral symmetry of C60 molecule. Notable changes...
nTL
Tongue cantilever Bridge diaphragm Post probe Fig. 6.1. Typical basic MEMS structures, which can be obtained by etching The microcomponents and features in microdevices are created either from the substrates or from the thin layer s of some specific materials e.g., the silicon dioxide layer . Assume that we are interested in fabricating a simple structure such as a step as shown in Fig. 6.1. An oxide layer is first deposited on the substrate Refer to Fig. 6.2 . The layer is not entirely used to...
Structure of Carbon Nanoballs CNBs
Carbon nanoballs belong to the fullerenes family, but they are a little different in structure. Other fullerenes as C60 are single walled, but nanoballs are multi walled. It is void in the center of carbon nanoballs but, in the wall of nanoballs, there is no hollow structure or channel as in the case of MWCNTs. Because their structures are similar to the onions, scientists call them bucky onions. Nanoballs in Fig. 11.16 have diameters of between 500 nm and 1 im Liu 2002 . Recently, our group...
References Jrr
Adzic RR 1998 Recent advances in the kinetics of oxygen reduction. In Lipkowski J and Ross PN ed Electrocatalysis, Wiley-VCH, pp 19-242 Adzic RR, Wang JX 1998 Configuration and site of O2 adsorption on the Pt 111 Electrode Surface, J. Phys. Chem. B 102 8988-8993 Aiken-III JD, Finke RG 1999 A review of modern transition-metal nanoclusters Their synthesis, characterisation, and applications in catalysis, J. Mol. Cat. A Chemical 145 1-44 Allen MP, Tildesley DJ 1987 Computer simulation of liquids....
Direct Amine Addition to Closed Caps and Wall Defects of Pristine MWNTs
The amidation reactions considered in the previous section have to do neither with graphene sheet chemistry, nor with fullerene-cap chemistry, but instead with the chemistry of carboxylic acids. On the other hand, all known covalent sidewall derivatisation reactions employ the chemistry of graphene sheet Bahr and Tour 2002 Dyke and Tour 2003 Hirsch 2002 Hu et al. 2003 Peng et al. 2003 Stevens et al. 2003 , although fullerene caps of pristine CNTs are reactive sites as well. It seems quite...
Subsystems and Devices for Miniaturised Spacecrafts Micropropulsion
The improvement of mission performances has two sides. On one side we would like to increase the volume of the payload to get more amount of information, cover a bigger data collection surface and to use less power for the antenna. This can be achieved through a payload distribution. In the same time we try to reduce cost by means of mass reduction and therefore we miniaturise the payload without loosing the performance and increasing the resolution. For the reasons of cost and feasibility the...
References Dju
Keown PA 1987 The role of precision engineering in manufacturing of the future, Annals of CIRP 36 495-501 Taniguchi N 1983 Current status in, and future trends of ultraprecision machining and ultrafine material processing, Annals of CIRP 2 573-582 Schey JA 1987 Introduction to manufacturing processes. 2nd edn., McGraw-Hill Book Company Shaw MC 1996 Principles of abrasive processing. Clarendon press, Oxford Jain VK 2002 Advanced machining processes. Allied publishers, New Delhi India Rhoades LJ...
Space Micropropulsion
The application of micro and nanotechnology to the aerospace field requires a very interdisciplinary knowledge and engineering approach. Since the first concept of a nanosatellite to be manufactured on silicon wafers was proposed by The Aerospace Corp. in 1995, many research groups are on the way to produce and demonstrate such an invaluable idea. The building of nanosatellites is related to cost reduction. However, in practice, the space community is still waiting for the boom of the...