Chemical and physical processes driven by multiphoton absorption make possible the fabrication of complex, 3D structures with feature sizes as small as 100 nm. Since its inception less than a decade ago, the field of multiphoton fabrication has progressed rapidly, and multiphoton techniques are now being used to create functional microdevices. In this Review we discuss the techniques and materials used for multiphoton fabrication, the applications that have been demonstrated, as well as those being pursued. We also consider the outlook for this field, both in the laboratory and in industrial settings. 相似文献
A flow injection micro-analyser with an integrated injection device and photometric detection is described. Channels measuring 205-295 μm depth by 265-290 μm maximum width were manufactured by deep UV lithography on two layers of urethane-acrylate oligomers-based photoresist. Hypodermic syringe needles (450 μm diameter) were connected to the channels for introduction of solutions into the system. Plastic optical fibres were connected to the ends of a 5.0 mm long channel, in order to conduct the light from and to a homemade photometer. The device has a total volume of 7.0 μL and three different sample volumes (0.09, 0.22 and 0.30 μL) can be inserted into the system by choosing the appropriate loop of the hydrodynamic injection approach. The micro-analyser, designed as a single line manifold, was evaluated by determining chloride in waters (mercuric thiocyanate method), and chromium (VI) in wastewater and total chromium in metallic alloys (diphenylcarbazide method). For chloride determination two micro-pumps were employed to impel the solutions, while for chromium determination this task was performed by a conventional peristaltic pump. The results obtained in all determinations did not differ significantly from the reference methods at a confidence level of 95%. In the chloride determination, a flow rate of 50 μL min−1 was used, providing a sample frequency of 45 injection h−1, generating ca. 0.7 mg of Hg(II) after an 8-h working day (ca. 20 mL of solution). This result suggests the potential of the micro-analyser towards the reduction of waste, following the philosophy of Green Chemistry. 相似文献
After deriving the approximation solution which describes the motion of neutral atoms in an optical standing wave field with large detuning, the spherical aberration and the chromatic aberration are analyzed and possible methods to reduce these aberrations are discussed. 相似文献
The representative soft lithographic techniques are used,which are micromolding and microtransfer molding methods to fabricate the micro array patterned titanium dioxide on glass substrates. Firstly titanium dioxide sol was synthesized by sol-gel method using tetrabutyl titanate as the precursor,then the pre-patterned poly(dimethylsiloxane) elastomeric stamp was used to mold the TiO2 sol on glass substrate by micromolding and microtransfer molding methods,micro patterned TiO2 sol was gelled at 70℃ with 0. 5 N pressure applied on the PDMS stamp,further heat treatment of TiO2 gel by annealing at 550℃ for 2 h produced the TiO2 microstructure. The TiO2 microstructure was observed by the optical microscope and the optical micrographs demonstrated the satisfactory yield and fidelity of pattern transfer by micromolding method and microtransfer method. The effect of gel temperature,the pressure applied on the PDMS stamp and the silicone mold on the fidelity and yield of TiO2 microstructure are discussed. 相似文献
A homopolymer of 9,9′‐bis[4‐(2‐(2‐tetrahydropyranyloxy)ethoxy)phenyl]fluorene and its copolymers with 3,4‐benzothiadiazole and 4,7‐di(3(4‐n‐octylphenyl)‐2‐thienyl)‐2,1,3‐benzothiadiazole were synthesized to produce a series of thermally reactive blue, green, and red luminescent polymers. Thermolytic removal of the tetrahydropyran (THP) group from polymer films, rendered the films insoluble due to the formation of hydroxyl groups on the termini of side chains. Thermal removal of the THP was lowered by up to 200 °C, when acid is present in the films. These polymers were found applicable to patterning by NIR direct thermal lithography, in conjunction with a NIR dye and thermal acid generator. The presence of the phenyl groups at the 9‐site carbon was found necessary to eliminate fluorenone formation, and enhance the colour purity of the material.