The isostructural calcium rare-earth oxyborates Ca₄RO(BO₃)₃(R---La³⁺, Nd³⁺, Sm³⁺, Gd³⁺, Y³⁺, Er³⁺, Tb³⁺, Lu³⁺)
as nonlinear optical materials have attracted great attentions recently. They belong to the monoclinic crystallographic system with space group Cm. The progress on the research of their structures and crystal growth was reviewed, and their linear/nonlinear optical
properties and self-frequency doubling properties were also summarized in detail. It was suggested that these crystals possess potential
applications in frequency conversion.

The recent progresses in the fabrication of the nano-scale materials, such as metalnano-particles or allied - powder, nano-tubes and nano-fabres (nano-rods), the self-organizationof the nano-materials and nano--composites, were mainly concerned. The virtues of some newpreparation methods were compared with general using ones.

The reaction mechanism and parameters that influenced the process of heating of ZrOCl₂ and Y(NO₃)₃ solution with an
alcohol-water mixture as a solvent to synthesize ZrO₂(3Y) nanoparticles, the influence of the reaction temperature and time on the synthesizing
process and final powder characteristics were investigated. It revealed that the reaction process could be divided into several steps according
to the occurring of different kinds of precipitates. As a result, Y(OH)₃ distributed uniformly in the gel of Zr(OH)₄ and then, when the
calcination temperature rose, the monoclinic phase in the powder decreased. Only when the reaction temperature was high enough that the dielectric constant decreased to <25, the precipitation could happen. To avoid
agglomeration, reaction time should be long enough to ensure the solution react complete.

By controlling the hydrolysis of titanium tetrachloride with adding (NH₄)₂SO₄ and NH₄OH, the
preparation process of superfine titania powder was investigated. As-prepared powders were characterized by XRD,TEM, SAEDand TG-DTA techniques. Both XRD
and SAED results showed that anatase phase existed in the sample dried at room temperature under vacuum and its primary particle size was about 3.8nm.
When calcined at 400℃ for 2h, it was the single anatase phase of titania and its primary particle size increased to 6.8nm, but rutile phase occurred at the temperature over 700℃ for 2h.

Fe₃O₄ magnetic powder coated with uniform SiO₂ layer was obtained by fluidized CVDtechnique. The oxidation mechanism and the kinetics of the SiO₂ coated Fe₃O₄ were investigated.The results show that the mechanism of oxidation of the SiO₂ coated Fe₃O₄ is inferred as phaseboundary reaction, spherical symmetry. The activation energy is increased with increasing silicacontent. The silica protect layer on the Fe₃O₄ magnetic powder formed by fluidized CVD techniquecan improve the oxidation-resistance of Fe₃O₄.

Li₂MnO₃ ultrafine powders were synthesized by the citrate sol-gel method using Li₂CO₃,
MnCO₃ as raw materials. The powder samples were characterized by DTA, TG, XRD and TEM. Ionic conductivity of the sinter was determined by
means of A-C impedance technique. The experiment results show that Li₂MnO₃ pure phase is formed at over 650℃. The diameter of the powder is below
50nm. The measured magnitudes of conductivities are in the range of 10^-6～10^-3s·cm^-1, the value of activation energy
is 44.87kJ·mol^-1 from 18℃ to 400℃.

The mesoporous SiO₂ xerogels with controlled texture were obtained using TEOS as precursor in the
presence of Polyethylene Oxide (PEO)- Polypropylene Oxide (PPO)- Polyethylene Oxide (PEO) by sol-gel method. By means of BET, TG/DTA, FT--IR and ²⁹Si
NMR analysis, the sol-gel chemistry was investigated and the effects of heat treatment in different conditions were also discussed. The results show that
the triblock copolymer molecular chain, additive amount and ageing time of SiO₂ sol can adjust available the texture properties of mesoporous
SiO₂, and in different atmospheres, the removed mechanism of such copolymer is different, which results in the different effects on the
mesoporous SiO₂. As a result, the mesoporous SiO₂ has stronger flexible skeleton, narrower pore distibution, and higher thermal stability
by vacuum heat-treatment.

TiO₂/ Poly(styrene maleic anhydride) nanocomposites were synthesized In situ via multi-component solution method. It was found that the
composites existed in the formation of covalent bonding between TiO₂ and polymer by infrared spectra. The systematical morphology change of TiO₂ in the composites with different reaction conditions was observed through transmission electron microscope. Based on the mechanism of “anchor wrapping”, the nanocomposites were in the form of three-dimensional net with the separated nano-crystalline TiO₂ micro-phases inside, and the aggregation of TiO₂ grains was successfully inhibitted. The anatase phase of TiO₂ was proved by X-Ray diffraction.

Dense silicon nitride ceramics were obtained from β-Si₃N₄ powder, the material wascomposed of small rodlike grains and equiaxed grains, the small rodlike grains dispersed uniformlyin the matrix. Sintering process consisted of three stages: rearrangement, grain shape regulate,grain growth. The microstructure was sensitive to the time at the beginning of sintering, andshowed stable when holding time was longer than 2h. High temperature increased the aspect ratioof rodlike grains. More additives increased the diameter of both equiaxed and rodlike grains.

Ordered mesoporous aluminosilicate materials with atomic Si/Al ratios of 16--64 were synthesized at a
very low molar ratio of surfactant/silica (0.12) by using aluminium chloride hexahydrate and TEOS as the sources of aluminium and silicon. The resulting
materials were characterized by XRD, TEM, FTIR and nitrogen sorption. As the NaOH/Si molar ratio increases from 0.2 to 0.6, the products obtained change
from hexagonal MCM-41 to cubic MCM-48. The quality of the product rapidly deteriorates as the aluminium content of the solid increases beyond a certain
limit. XRD shows that the substitution of the silicon by the large aluminium atoms leads to the expansion of the unit cell.

Two kinds of Si₃N₄ starting powders with different α/β ratios were used to prepare
Ca-α-Sialon with the composition Ca_1.8Si_6.6Al_5.4O_1.8N_14.2 by pressureless sintering. The densification process, reaction
sequence and microstructure of the corresponding materials were studied by XRD analysis and SEM observation. Elongated α-Sialon grains were observed in the materials sintered
with either Si₃N₄ starting powders. On the other hand, Si₃N₄ starting powders with high β phase content resulted in poorer densification
during sintering and the temperature for complete dissolution of β-Si₃N₄ was 100℃ higher than that for α-Si₃N₄. The higher the content of β phase in the starting powders, the fewer nucleation sites there were, and the coarser α-Sialon grains were.
A broad size distribution of the Si₃N₄ starting powders led to the inhomogeneity of α-Sialon grain sizes.

By using Guinier-Hagg camera, computer-linked scanner system and associated programs, the lattice parameters of α-Sialon for the
compositions (Ca_0.5Mg_0.5)_xSi_3-xAl_xO_xN_16-x with x ranging from 0.3 to 1.4 were determined. The samples were prepared by hot pressing technique. The
results showed that the crystalline phases in the sintered materials consist of α-Sialon and Mg-containing AlN-polytypoid when x is equal to or
greater than 1.0 and the lattice parameters of (Ca,Mg)-α-Sialon are obviously smaller than Ca-α-Sialon with the same compositions. EDAX
results further revealed that 90% of added Ca⁺⁺ and small amount of Mg⁺⁺ are incorporated into α-Sialon. This result combined with
the fact of formation of magnesium-containing AlN-polytypoid phase in (Ca,Mg)-α-Sialon samples can provide a valid approach to reduce the
amount of glassy phase at the grain boundary.

A novel microstructure of TiC /TiB₂ / MoSi₂ composite and its effect on mechanicalproperties were studied. The results indicate that hollow particles, consisting of TiC and TiB₂ nanosized grains, can be formed in MoSi₂ matrix when the mixed powder of elemental Ti, B₄C and MoSi₂ was reactively hot pressed. The bending strength of these composites with the newmicrostructure reaches at 480 MPa, and the highest fracture toughness is 5.2 Mpa·m^l/2.

The layer and in-plane structure of CuCl₂-GICs, synthesized with expanded graphite, was detected by TEM. The I_c values of the 2-,3-,4-stage
CuCl₂-GICs calculated on the X-ray diffraction patterns was similar to the theoretical values. The parameter of the in-plane structure was calculated
on the selected area electron diffraction pattern. The diffraction spots of the GICs consist of single spots of carbon atom plane of graphite and triple
spots of chloride. The single spots imply that carbon atom of the in-plane of GICs is put in the order of the hexagonal net of graphite. Compared with
the size of carbon atom, the triple spots of chloride signify that there are three sizes of the molecule of cupric chloride. According to the lattice of CuCl₂-GICs,
there are three kinds of super-structure:(2×2)R(30°, (7^1/2×7^1/2)R(0°), (3^1/2×3^1/2)R(0°). The angles of the lattice of cupric chloride and carbon atom are 30° in
the 2-stage and 3-stage CuCl₂-GICs, 0° in 1-stage CuCl₂-GICs. According to electron diffraction pattern, high resolution image, chemical compounds
analyses, XPS-ESCA and XAES, the frame of micro-structure of the CuCl₂-GICs was made.

Self-cleaning ceramic materials were prepared by coating photocatalytic membrane on ceramic matrix. The photocatalytic behavior of these materials
for degradation of oleic acid and sterilization was studied by using XRD, AES, and in-situ reaction techniques. The effect of preparation and reaction
conditions including heating treatment and thickness for the membrane on photocatalytic activity of the self-cleaning ceramics was examined. The
results show that the photodegradation of oleic acid and sterilization of the self-cleaning ceramics are determined by crystal structure,
particle size, and specific surface area of the supported photocatalyst membrane．

The influence of oxide such as CuO and MnO₂ which have the character of decomposition accompanying with oxidation on the TiO₂ capacitor-varistor ceramics was studied. Based onthe results of C - V analysis, I - V analysis and dielectric measurements, their working mechanismwas analyzed. The results show that the decomposition accompanying with oxidation is useful forincreasing the surface state density and the height of grain-boundary barrier, and therefore improves the nonlinear property of TiO₂ capacitor-varistor ceramics.

Transverse field-induced strain (x₂-^E), hysteresis loop (P-E), dielectric constant and piezoelectric
coefficient under DC bias were measured for 3mol% barium-doped PLZT 10/65/35 relaxor ferroelectric ceramic. Dynamic dielectric constant and piezoelectric
coefficient were calculated according to the slope of x₂-E and P-E curves respectively. Dynamic dielectric constant is much larger than DC biased dielectric
constant as the electric field is less than 8 kV/cm, the difference between them is getting smaller as the electric field increases. Dynamic piezoelectric
coefficient is much larger than the value under DC bias as the electric field is in the range of 3--15 kV/cm, the difference between them is small as
the electric field is less than 3 kV/cm or higher than 15 kV/cm.

The pyrochlore-free Bi₂O₃ doped lead magnesium niobate ceramics were fabricated through columbite
precursor method and their B-site ordering structures were characterized by XRD and SAED techniques. With the increase of the ratio between
Mg²⁺ and Nb5⁺ cation content, hexagonal Mg₄Nb₉O₆ becomes coexisting with orthorhombic MgNb₂O₆ in the columbite precursor.
The donor doping with Bi³⁺ can compensate for the space charge generated by the nonstoichiometric order and thus promotes the growth
of ordering regions. Moreover, the ordering degree of PMN can be increased pronouncedly with the increase of bismuth cation content
of the specimen. The average size of ordering microdomains estimated in PMN-0.05Bi specimen is about 22nm.

(1 - x)Pb(Mg_1/3Nb_2/3)O₃-xPbTiO₃ (PMN-PT) ceramics with x near morphotropicphase boundary (x=0.25~0.40) were prepared by Columbite technique. The influences of PT content and preparation process on dielectric, ferroelectric and piezoelectric properties were studied.The results show that ceramics with x between 0.32 and 0.35 possess higher dielectric constant,piezoelectric constant, coupling factor and lower mechanical figure of merite. The properties arecomparable to best soft PZT ceramics.

TEM, XRD, hardness measurement were employed to analyze the microstructure ofsilver halide polycrystalline infrared fiber. The polycrystals are the host of the fiber with mosaicAg nanocrystals. The fiber microstructure has an effect on the scattering loss. The fiber grain sizeand microhardness can be changed through different processing.

The silver halide was purified by melting at high vacuum, zone melting with reactive atmosphere and crystal growing in quartz ampoule with high vacuum.
The silver halide fibers were made by hot extrusion. The effects of the purification of silver halide and its fiber preparation method on transmission loss were studied. Experiment results show that the increase of the number
of times of the starting material purification will cause the decrease of absorption coefficient of silver halide preform. A high quality preform was
obtained by a reasonable technology. The absorption coefficient of the purified　silver halide preform measured by CO₂ laser calorimeter is less than 5×10^-4cm^-1. The transmission loss of the silver halide fiber is 0.3--0.5dB/m when measured by CO₂ laser beam at 10.6μm. Its output
power of transmitting CO₂ laser beam is more than 20W in the fiber of 1.0mm diameter and 1.64m length.

The whole process of preparing La_0.8Sr_0.2CoO₃ oxide powders by a cellulose adsorp-tion method was investigated by TG, DTA, XRD, and CO₂-TPD
techniques. It was found that cellulose first acted as an adsorbent. During the initial stage of pyrolysis, the cellulose was partially oxidized, and some
carboxyl groups were formed in the cellulose texture, which was then complexed with the metal ions. At optimized condition, pure phase LSCO powder could be
acquired at low temperature. But, if the produced CO₂ could not elute in time, carbonate would form during pyrolysis, and a calcined temperature higher than
800℃ was needed.

β-SiC thin films were heteroepitaxially grown on (100)Si substrates at a temperaturerange from 1000 to 1400℃ by atmospheric pressure chemical vapor deposition (APCVD) process.Experimental results show that the epitaxial layers change from polycrystalline silicon into singlecrystal β-SiC state with the deposition temperature s increasing, but the growth rates of singlecrystal films decrease inversely.

The microstructure and the electronic conductivity of plasma sprayed boron carbidecoating were studied. The results show that B₄C phase in the coating exists in two major structuregrained and flaky structures. Metal Fe as the impurity phase in the coating is the key factorresulting in the abnormality of electronic conductivity of B₄C coating. Another impurity phase,which consists of B, C and Fe elements, will decrease the microhardness of B₄C coating.

The microstructure of Ti-Cr-Si protective coatings modified by different additives onC-103 niobium alloys before and after oxidation and the influence of these additives on the structureand oxidation resistance of the silicide coatings were studied. The results show that the oxidationresistance of Ti-Cr-Si coating modified by Ge, Mo, W decreases, but the oxidation resistance ofTi-Cr-Si coating modified by Zr and Al increases at high temperature.

Surface modification of Si₃N₄ particles by acid leaching and its effects on the colloidal behavior and the flow properties of Si₃N₄ aqueous
slurries were investigated. The experimental results indicate that the isoelectric point of Si₃N₄ particles shifts to basic region after
modification due to the decreasing of the oxidizing degree on the surface of Si₃N₄ modified. Because the Zeta potential of Si₃N₄
particles increases efficiently, the flow properties of Si₃N₄ modified slurry significantly improve and the maximum solid loading
increases from 50 to 55vol.%. Moreover, the 53vol.% Si₃N₄ slurry suitable for casting was prepared.

YAG-Al₂O₃ nanocomposite powders were prepared by the co-precipitation process. The crystallize temperature and morphology of the composite powder
was intensively studied with XRD and TEM. The results indicate that above 1300℃, there is only YAG and α-Al₂O₃ phases existed.
YAG particles with an average size of 100 nm can be observed uniformly dispersed in α-Al₂O₃. Using prepared powders, nearly fully dense sintering
body can be fabricated by hot-pressing at 1450℃. The sintering temperature is far lower than 1600℃ reported by other researchers. The preparation
of YAG-Al₂O₃ nanocomposite powders based on the co-precipitation method has promising application with merits of low cost, high production and simple processing.

The effect of magnetic field on temperature distribution in KNbO₃ melt was experimental studied. By utilizing a special temperature
measurement technique, the KNbO₃ melt temperature distribution in a 2mm diameter platinum crucible was measured under 0, 70, 117, 135mT transverse
magnetic field respectively. The results show that the temperature gradient along crucible radius decreases with magnetic intensity increasing, especially,
the temperature gradient close to crucible-melt interface where the buoyancy-driven convection is the main convection form decreases greatly. It may
implie that magnetic field can damp up the buoyancy-driven convection in KNbO₃ melt.

The relationship was investigated between lattice constants and thermal stability of
aluminium titanate (Al₂TiO₅). Through studying the variation of lattice constants of Al₂TiO₅ with temperature, the authors discovered an abnormal
phenomenon that lattice constant c of Al₂TiO₅ decreases with the increase of temperature. The authors proposed that the thermal stability of
Al₂TiO₅ is closely related to its lattice constant c. Different additives were added to Al₂TiO₅ to change its lattice constants.
The stability of Al₂TiO₅ can be reflected by its lattice constant c. The larger lattice constant c, the more stable aluminium titanate. Lattice constant c corresponds to the height of the
distorted [MeO₆] octahedra in the crystal structure of Al₂TiO₅ and its increase will lead to a reduction of distortion of the octahedra,
so that the stability of Al₂TiO₅ is improved. The effect of firing process on lattice constants and stability of Al₂TiO₅ was also explored.
The result shows that with increase of firing temperature and extension of soaking time, aluminium titanate exhibits larger lattice constant c and its
stability increases correspondingly.

Zeta potential of YAG powder was measured, and well-dispersed YAG aqueous suspension could be obtained through regulating pH value. Al₂O₃-YAG
composite powder containing uniformly distributed YAG was prepared by using the heterogeneous precipitation method. Sintered bodies were gotten by hot-pressing,
and addition of YAG influenced little on sintering temperature. Bending strength and fracture toughness of Al₂O₃-5vol%YAG composite were 485MPa and
4.2MPa·m^1/2 respectively. Both were higher than those of monolithic Al₂O₃ ceramics, and the reliability of values was also better than that of
Al₂O₃ ceramics. Through TEM observation, it could be seen that YAG particles were uniformly distributed throughout materials. It indicated that Al₂O₃-YAG
composite with good YAG dispersion could be obtained by using the heterogeneous precipitation method.

The microstructural characteristic of (Y+Sm) α-Sialon with different amount of AINpolytypoid was studied by SEM and EDS. The formation mechanism of elongated α-Sialon inα -AIN-polytypoids dual-phases area was discussed. The results show that with increasing amountof AIN-polytypoid, more α-Sialon grains exhibit the enlongated morphology.

The ion energy is a crucial parameter for amorphous diamond films deposition. Amorphous diamond
films (a-D) were prepared by magnetic field filtered plasma stream system. The Raman spectroscopy and surface morphology of a-D films deposited at various substrate bias voltages V_b were studied. The
results show that a-D films, deposited at V_b in the range from --10V to --50V, have a single and nearly symmetric very broad Raman
peak range from 1200cm^-1 to 1800cm^-1. The surface morphology of these films is very smooth and uniform. However, for samples deposited
at V_b>-10V or V_b<-50V, the Raman spectra exhibit two broad peaks centered approximately at 1350cm^-1(D peak) and 1580cm^-1(G peak), and the surface roughness will be increases.

The influence of basic processing parameters on the deposition of a-CN_x was studied.The results show that the increase of N flux enhances the deposition rate of the film as well asincreases its N content. While higher sputtering power leads to higher deposition rate. Further-more, the employment of bias will prove to be beneficial in the preparation of CN_x film in thatit not only facilitates the densification process and produces a smoother surface morphology, butalso increases the content of N in the film.

The chemical states of In, Sn and O in Sn-doped In2O3 films were investigated byusing X-ray photoelectron spectroscopy. The results indicate that Sn and In respectively exist ina same chemical state for both as-deposited and post-annealed films. Two types of O2- ions, OI and OII, can be distinguished by Gaussian simulation. OI has a binding energy of 529.90±0.30 eVwhich is in oxygen sufficient region, and OII has a binding energy of 531.40±0.2 eV which is inoxygen deficient regions. Oxygen deficient regions mainly exist in the surface layer.