1. Introduction
Titanium dioxide has been widely used in industrial
applications due to its high gas sensitivity, excellent
dielectricity, and chemical- and photo-catalyzing properties.
1-3 The crystalline titanium dioxide exists in different
forms, such as rutile, anatase, and brookite.4
Brookite and anatase are thermodynamically metastable
and can be transformed exothermally and irreversibly to
rutile at higher temperatures. The transition temperatures
reported in the literature ranged from 450 to 1200
°C.5-8
Nanomaterials have been attracting extensive attention
because of their unique and often improved mechanical,
electrical, optical, and chemical properties as compared
with conventional polycrystalline materials. Various
synthesis methods, such as hydrolysis,10 sol-gel,7-9 microemulsion
(or reverse micelles),5-6,15-16 and hydrothermal synthesis,11-14 have been used to prepare nanoparticles
of titania. Compared with the other methods, hydrothermal
synthesis could be carried out at a relatively low
reaction temperature (<250 °C) to produce a sufficiently
crystalline product without the necessity of post-calcination.
17,18 Hydrothermal preparation of ultrafine TiO2
powder has been published in several works.11-14 By
changing the hydrothermal reaction conditions, such as
reaction temperatures,pHvalues, reactant concentrations
and molar ratios, additives, and so forth, crystalline
products with different compositions, structures, and
morphologies have been generated.11-14,17,18 However, the
increase of reaction temperature and/or reaction time
would usually result in the formation of a polydispersed
powder.18,19 It is of great interest to confine crystal growth
during hydrothermal aging to obtain monodispersed
powder by using a controllable technique, for instance, by
using microreactors.
以上回答不够满意，请大神现身！
追答有些词没有翻译过来的缘故是这些词太少见了，查遍所有词典都找不到。所以只好凭借楼主的聪明才智来猜词义了。其实在英语学习的过程中，学习过程中学会猜词义也是尤为重要的。