Inclusion complexations of α- and β-cyclodextrin (CD) with a series of phenol and benzoic acid derivatives both in vacuo and in water were investigated by semiempirical PM3 method. The inclusion systems with a higher negative value of complexation energy or interaction energy were found to have also a larger value of formation constant (Kf) in aqueous solution. The stability of β-CD inclusion complexes depended on the size/shape-fit between host and guest. A good size fitting between the volume of a guest molecule and the free space size of CD cavity effectively improved the stability of CD inclusion complex of the guest. Even though there was no appropriate molar volume ratio (MVR) of a guest to β-CD cavity, a good structural matching between the shape of a guest molecule and the arrangement of β-CD cavity should also obviously improve the stability of β-CD inclusion complex of the guest. Moreover, the CD cavity size exerted a big influence on the stability of these supramolecular complexes. There was an energetic advantage of larger than 45 kJ mol−1 in favor of the intermolecular complexations between α-CD and mono-ortho-substituted phenol derivatives relative to phenol or mono-para-substituted phenol derivatives.

This paper briefly introduced the principle and technology development of Abrasive Air Jet Micromachining (AAJM). AAJM is able to create fast and inexpensive 3-dimensional microstructures of brittle materials. The application fields of AAJM are expanding widely over electronic parts, semiconductor and small parts of MEMS. The advantages and challenges are discussed.

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Aiming at the shaft pressing and assembling process for steel shaft and small gear, which is frequent in toy gear reducer assembling, a reconfigurable and multi-station auto shaft pressing and assembling machine had been developed. In the machine, steel shaft and small gear are positioned in a pre-positioned fixture in advance. The assembling process is carried out in three stations simultaneously. It makes the machines efficiency become higher. Applying the reconfigurable design concept, the machine can be divided into basal modules and changeable modules. The changeable modules can be adjusted or replaced to make the machine fit for components of multifarious small gears and steel shafts with different length and diameter. Each module of the machine is introduced in detail and related problems are discussed in the paper.