An introduction of recent progresses on the studies of lattice defects in lead tungstate crystals is presented. These results demonstrate the importance of taking into consideration in influence of lattice defects on performance of PWO scintillators. The relation among nonstoichiometry, crystal structure / polymorphism, impurity effects, oxygen composition and properties of scintillators is briefly discussed on peculiarities of PWO crystals.

There are many advantages of PbF₂ crystal for usmg as a scintillating material in high energy physics research. The research history on the lummescence and scintillation of PbF₂ crystals was reviewed, especially on the lummescene characteristics under the conditions of low temperature,phase transition and doping. The existing problems and solving methods were mentioned.

The progress in study on Bi₂O₃-SiO₂ system was introduced in this paper. Stable and metastable phase equihbriums of the system were first summarized and reviewed, then several aspects such as structure, performance, growth and application of bismuth silicate compounds, in-cluding Bi₁₂SiO₂₀, Bi₄Si₃O₁₂ and Bi₂SiO₅, were discussed. Bi₂SiO₅ may be one of the promising new functional crystal.

Glass ceramics with α-cordierite(2MgO·2Al₂O₃·5SiO₂) as main crystal phase, having low dissipation factor in high frequency range, are excellent materials
for microwave substrates. However, the dielectric constant of the material is not high enough for some applications. Recently, a novel glass ceramic with
dielectric constant higher than 7.0 and dissipation factor lower than 1.5×10^-4 (in the frequency range >1GHz) was developed. The density changes and the expansion
-shrinkage behaviour during crystallization process of the material were measured. The relationship between electric properties and composition and micro-structure
of the glass-ceramics was studied by X-ray diffraction (XRD), scanning electron microscope (SEM) and electric property testing. The results show that:
(1) The changes of the density and volume of the materials during heat-treatment are caused by crystal phase transition. It’s possible to avoid the sample from
cracking during heat-treatment by selecting suitable heat-treated cycle. (2) The volume ratio of α-cordierite to MAT, the two main crystal phases in
the glass-ceramic, influence the dielectric constant of the material. Furthermore, the more developed crystal grain is of benefit to increasing of
dielectric constant.

Optically transparent 50BaO.50B₂O₃ (in mol%) glass-ceramics, containing grain-oriented transparent β-BaB₂O₄ surface crystallized layers, were successfully prepared by the conventional melting-quenching technique and subsequent controlled heat treatment. SEM showed that the surface cystallization layer was about 2μm in thickness, and the crystallite diameter about 0.2μm.Second harmonic generation (SHG) signals were observed using 1.064μm Q-switched Nd: YAG laser.

By selecting phase-separable glass system Na₂O-Al₂O₃-B₂O₃-SiO₂ as the base glass and by introducing Cu⁺, I^- from the starting materials
CuO/SnO and NaI respectively, CuI microcrystal doped borosilicate glasses have been prepared successfully. The microcrystal and its distribution
in the glass medium are observed by means of X-ray diffraction and HRTEM. The effects of heating treatment on the optical absorption of glasses
is studied through the room transmission spectra of glasses. The electroinduced second harmonic generation in the glasses is reported. The
mechanism of this effect is also discussed.

Nanometer-sized SnO₂ particles were prepared by a sol-gel method using inorganic salt as a starting material. The crystallization process of the nano-SnO₂
was investigated by means of TG--DTA, IR absorption spectra, X-ray diffractometry and TEM. The investigated results indicated that the grain size of SnO₂
increased slowly with annealing temperature up to 500℃ but grew rapidly when the annealing temperature was higher than 600℃. Well-crystallized nano-SnO₂
with size 10～20 nm was obtained at 600℃. The activation energies for growth of nano-SnO₂ were calculated to be 7.02kJ·mol^-1 with the
annealing temperature up to 500℃ and 26.55kJ·mol^-1 when the annealing temperautre was higher than 500℃. The advantages of nano-SnO₂
as a material of gas sensor were also discussed.

Nanosized silicon nitride powders were synthesized by using silica sol, urea, and carbon black with the process of sol-gel and carbothermal reduction. Ammonolysis of the aqueous
solution of silica sol and urea resulted in the formation of an ammono precursor. The effect of ammono precursor and silica sol on the synthesis of Si₃N₄ powders was investigated. The
results showed that using ammono precursor dehydrated can accelerate the reaction rate and increase the nitrogen content of Si₃N₄ powders. Synthesis of nanosized Si₃N₄-Y₂O₃ composite
powders from the homogeneous mixture of Y(NO₃)₃ and silica sol in the liquid state was also studied.

CuO/Al₂O₃ powders were prepared from aqueous solution by ultrasonic spray pyrolysis in the toil plume region of high-frequency inductively coupled plasma. The morphology of the initial powders
varied with the atomic ratio of Cu/Al and the concentration in Cu(NO₃)₂-Al(NO₃)₃ solution. Al₂O₃ powders had spherical internal void structure and some shell fragments. CuO powders composed
of a mixture of amorphous and ultrafine crystallite, some tens of nanometres in size. The compound powders of CuO/Al₂O₃, with Cu/Al atomic ratio 1:1, had a similar morphology to pure
CuO powders. The diversity of fusing point between CuO and Al₂O₃ was the main factor to cause the different micro-processes of powder formation in h.f thermal plasma with a plate power
about 1kW.

Ultrafine oxidized tin particles with particle size about 6nm were prepared by inert gas condesation deposition under low oxygen pressure.
The nanostructure, hyperfine parameters and chemical stability were studied by means of TEM, XRD especially by Mossbauer spectra analysis.
Results show that, the nanostructure of particles can be divided into crystal component and disorder component. Nano-powders have high chemical
activity and can be oxidezed into stable SnO₂ compound at ambient temperature. XRD measurements show, post-annealing at temperature of 300～
600℃ for 2h in air produces orthorhombic and tetragonal SnO₂ phases. Orthorhombic SnO₂ phase may be an intermediate phase while disorder SnO₂
transforms to high temperature stable tetragonal SnO₂ (rutile) under oxygen deficiency condition.

The spectra of write, read and output in SrS(Eu, Sm) were reported. The linearity of outputing-stimulated luminescence intensity versus writing-light intensity and reading light- in-tensity were given. The function of image storage and image addition and subtraction were exper-imentally demonstrated, using SrS(Eu, Sm) film whose thickness is approximately-100μm. The results show that this material has very greatly potentiality for application in optical information storege and processing.

The fabrication technology of Na-β"-Al₂O₃ ceramic tubes by reaction sintering, i.e., by decom-position of the starting materials at 900℃ followed by reaction sintering and stepped annealing for phase transformation, was investigated. The Na-β"-Al₂O₃ tubes thus prepared have fine properties and the duplex microstructure can also be controlled in a certain degree.

The dimensional effects of breakdown strength, nonlinear coefficient and change in breakdown strength due to current impulse were experimentally studied. The distribution of ZnO grain size was statistically analyzed, which was obtained to be normal distribution. A microstructure model was proposed. The thickness dependence of the breakdown strength E_1mA obtained by means of computer sinmlatiou is the same as cxperimental one. The critical thickness d_c is proportional to the product of variance σ² and average length μ of ZnO grains.

A kind of symmetrical electrochemical cell of the type M, M_xO_y|ZrO₂(MgO)| M, M_xO_y was used to study the polarization characteristic of solid state reference
electrodes at high temperature. Experimental results show that the variation of overpotential with polarization current is linear. The exchange current
desities for the Mo/MoO₂, Cr/Cr₂O₃, Ni/Ni/O and Co/CoO electrodes, in the order named, are decreasing. The exchange current densities of all kinds of
electrodes are also increasing with the increase of metal ratio in reference electrodes and temperature. The activation energy of the electrode reactions was calculated.

Stability of BaO-TiO₂-SiO₂ sol-gel derived coatings in Portland Cement was studied by the scanning electron microscopy, X-ray fluorescence analysis, secondary neutral mass spectrometer,and X-ray diffrastion. The results showed that BaO-TiO₂-SiO₂ coatings can protect the silicate glass substrate against the attack of saturated Ca(OH)₂ and Portland cement aqueous solutions at 80℃ for a long period of time. The long term stability of GRC composites reinforced with coated E-glass fibers is apparently improved.

Carbon nitride thin films were deposited on Si (100) substrates using the RF-reastive sput-tering technigue. These films were characterized by transimssion electron microscopy, infrared spectroscopy, X-ray photoelectron spectra (XPS) and X-ray diffraction (XRS). It was found that the structure and morpho1ogy of the CN films varied with deposition parameters. Under optimum conditions, β-C₃N₄ phase was synthesized.

Lithium was inserted electrochemically from an electrolyte into V₂O₅ thin films prepared by evaporation and posttreated at different temperatures in air
so that Li_xV₂O₅ was obtained. Li⁺ storage properties, reversibiliy of Li⁺ intercalation/deintercalation in V₂O₅ thin films and influence of
Li⁺ insertion on their optical properties were investigated. The experimental results show that two factors, the V⁵⁺ concentration and the sum total of
sites in V₂O₅ thin films, control the capacity of Li⁺ insertion into V₂O₅ thin films, and that these thin films have a good Li⁺ storage characteristic,
stability and reversibility.

The quantitative phase analysis of zirconia powder treated with various temperatures and times was performed based on X-ray profile diffraction data and
Rietveld method. The results showed that zirconia powder obtained by 500℃ heat treatment for 2h was a cubic and tetragonal mixture with the weight ratio of 48:52,
whereas cubic phase disappeared in zirconia powder after 700℃ treatment for 2h and part of tetragonal phase was transformed into monoclinic phase at the same time with the
weight ratio of tetragonal to monoclinic 35:65. Almost pure monoclinic phase was obtained when zirconia powder heated at 800℃ and 900℃ for 8h and 2h respectively
and the tetragonal contents in these two cases were about 5 wt% and 1 wt% respectively. The effect of temperature and time of heat treatment on the size of grain of zirconia
powder was also discussed.

SEM, X-ray Diffraction and Reflected Polarized Micrography using crossed polarizers were employed to investigate the orientation of unidirectional C/C composites matris mesophase pitch in 0.8T magnetic field and verified that the mesophase layers of the C/C composites were parallel to magnetic field s direction. It was found that the mesophase layers of the C/C composites in the magnetic field were perpendicular to the carbon fibers.

It is found that the interface in unidirectional C/C composits fabricated with mesophase pitch in O.8T magnetic field belongs to TOG (Transversely Oritented Graphite), a kind of weak interface in the composites, and the flexural strength of this kind of composite decreases slighty. In addition its ductility increases strongly. The work here is an effort to investigate the influence of TOG on the mechanical propertics of the composites.

The ceramic bodies (including origin, green and gross bodies) were effectually detected with nondestructive ultrasonic technique
in the ground of 20～50MHz operating frequency, by means of the directly coupling method with a delaying block.

The microstructural anomaly of materials, which may appear in each of the preparing steps can sensibly be responded by the acoustic
parameters (velocity and attenuation). The choice of optimum operating frequency and coupling condition is necessary for a creditable detection
of green and gross bodies with defect by using ultrasonic technique.

The longitudinal and transverse transducers having plane and curved surfaces with 20～100MHz frequency were planed
and prepared. The acoustic parameters and defect size within ceramic parts of engine were determined by means of directly coupling mode. the creditability of measurement was improved by
alternately using longitudinal (susceptible to pore) and transverse (satisfying with measurement of crack) transducers. As a result of numerous measurements the relational curves of “distance-
amplitude-normal” of defects were established for searching the size of defects within materials measured. On the basis of determination,
according to the theory of fracture mechanics, the quality evaluation and classification of ceramic parts can be made for judgment of pass/abandonment.

Ultrafine powders of Y₃Al₅O₁₂(YAG):Ce³⁺ were prepared by the ployacrylamide gel, and the spectra characterization of the powders was studicd. Compared with coprecipitation process, YAG phase can be got at lower temperature (900℃) by the polyacrylamide gel. The blue-shift in the spectra of ultrafine YAG:Ce³⁺ powders was found.

The investigations were mainly focused on the phase composition, microstructure and fatigue behavior of fully-dense Y-α/β-Sialon
ceramics prepared from powder mixtures of Si₃N₄, AlN and Y₂O₃ by using gas pressure sintering technique.

The results obtained show that the typical microstructure of mixed Y-α/β-Sialon ceramics consists of needle-like grains of the β-phase and equi-axed α-Sialon grains
with a small amount of glassy phase and J-Y4Si₂O₇N₂[102] crystalline phase on grain boundaries.

The cyclic fatigue crack growth behavior from microindentation flaws was investiated with gas pressure sintered Y-α/β-Sialon ceramics, A V-shape behavior was observed in the relation between the maximum applied stress intensity factor and crack
growth rates which are sensitive to the level of applied stresses.

A polymer ionic conductor, containing bis(3,4-dicarboxyphenyl) ether dianhydride (BPDA), 4-aminophe-nyl ether (ODA), lithium perchlorate and inorganic material was
synthesized by linear condensation polymerization method. A. C. complex impedance method was used to determine the electrical conductivity of copolymer films. The results
show that the influence of inorganic material kind on conductivity of the system is greater than that of grain size. Adding SiO₂ either 0.96μm or <0.1μm, into BPDA
-ODA/LiClO₄ system, the electrical conductivity of copolymer at 200℃ is about two times over the original.

A new physical model and calculating method to large-scale and high temperature industrial furnace was deeply studied. A new technique of thermal insulation and optimum method of thermal design of materials was proposed. After thorough test and verification in engineering, the value of design was identifed with that of measurement and the beneticial result of saving energy was remarkable.

Nanocrystalline titania powder was obtained from titanium tetrachloride by chemical method.After hydrolysis of titanium tetrachloride, one sample was neutralized by NH₃.H₂O at once, and the other was neutralized one day later. The former was detected to be sphericed anatase titania,whereas the latter a mixture of anatase and rutile titania. Both samples have the average diameters of 15nm, ranging from 10 to 20nm. Phase transformation from anatase to rutile occurs at 923K,and its activation enthalpy is 113.5±8．97kJ／mol．

Using DTA measurement on nanocrystalline brookite TiO₂ sample, we found two endothermic peaks on DTA curve. From XRD analysis of the original nanocrystalline TiO₂ and its heat-treating samples, we obtained the following results: the irst
endothermic peak (peak A) corresponds to the desorption of physical or chemical absorption; the second one (peak B) is elated to the first order phase transition from brookite to anatase then to rutile, and this structural phase transition is neficial
to the growth of nanocrystallilne grains.

Based on the phase relationships in the Dy-Si-Al-O-N system, α-Sialon ceramics and α-β-Sialon composite ceramics with garnet and/or melilite as grain boundary phases were designed. The densification behavior, α’→β’ phase transformation in heat-treatment, mechanical properties and microstructure characteristic were studied. The results show that Dy-α’ and Dy-α’-β’ ceramics with garnet and/or M’ as grain boundary phases can be fabricated by HP. DyAG as an additive is more effective than M’ in promoting densification. Dy-α’ is kinetically more favourable to be formed over the other Dy-containing phases unlike the other Ln-α-Sialons, thereby the fractions of the α’ phase in the as sintered specimens is higher than the designed ones. By post sintering heat-treatment, the α’→β’ phase transformation occurs and the designed
α’/α’+β’ ratios can then be achieved.

Dianmond films were deposited on Al2O3 ceramic substrates by oxygen-acetylene flame, the morphologics and their distribution of deposited films on the substrate surfaces were also observed.Proper pretreatment of substrates can increase the density of diamond nuclei. An intermediate eas-ily be formed betweem Al₂O₃ ceramics and deposited diamond filmes. The mechanism of depositing diamond films on Al₂O₃ ceramics was preliminary analyzed.

The phase diagram of diamond deposition in atmosphere oxyacetylene flames was calculated according to our non-equilibrium thermodynamic coupling model, and the ranges of substrate temperature and gas flow ratio for diamond growth were obtained theoretically. The suitable range of gas flow ratio (R) is dependent on substrate temperature (T). Since substrate temperatures between 1000K and 1250K are usually used for diamond growth in oxyacetylene flames, the suitable range of flow ratio of oxygen to acctylene will be lying between 0.8 and 1.1. Diamond can not be synthesized for any R value when substrate temperature is too low. The suitable range of substrate temperature for diamond growth is also dependent on gas flow ratio of oxygen to acetylene. The temperature range is widest for R value close to unity, and the range will be narrowed rapidly when R value deviates from unity. The diamond growth conditions obtained in the paper are consistent with many reported perimental
results, and favour experimental designs for diamond deposition in oxyacetylene flames.

A fundamental study of the influence of electroless nickel plating on PTC effect in some semiconducting ceramics of (Ba_1-xPb_x)TiO₃ was made by comparison experiment. It was discovered that in some dense PTC ceramics the influence of nickel plating was not due to the permeation of plating solution into the ceramics, but was related to the reactions in the course of nickel plating. It was first proposed in this paper that nascent hydrogen generated in nickel plating could have influence on PTC effect.

A prototype of the all solid state WO₃/NiO complementary electrochromic device was designed and manufactured on the basis of the inverstigation on the ionic conductivity of polyethylene glycol gel eletrolyte doped with lithium erchlorate
and propylene carbonate, and the Li⁺ ion intercalation performance of sputtered nickel oxide and tungsten oxide thin films.
The electrochromic performances of the devices were studied by cyclic voltammetry and spectrophotometry. The results ndicated that the laminated WO₃/PEG-LiClO₄-PC/NiO complementary electrochromic devices have excellent electrochromic characters in
vis-nir region with the transmittance 0.70 in the bleached state at 600nm and 0.20 in the colored state.

The effect of additives on mechanical properties of rapid CVD oxidation ---resistant C/C composites was explored by orthogonal design test method. The optimal composition was determined. The experiment results show that the initial oxidizing temperature, flexural strength and flexural modulus of C/C composite manufactured by optimizing composition are 657℃, 254MPa and 49MPa respectively. The regular of effect of additives on mechanical properties of this kind material was analyzed.

Sulfur-free and expanable graphite was prepared by reacting of natural flake graphite with concentrated nitric acid and acetic acid using potassium permanganate as oxidant at 30℃. The best conditions of the preparation were screened out. The method of Mass Spectrum was utilized to analyze the expandable graphite.

The effects of disturbed and false signals on Scanning Electron Acoustic Microscope (SEAM) are presented in this paper. Various reasons such as high electric fields, magnetic fields and high frequency instruments causing the disturbed signals on SEAM are discussed and a sample of detection assembly is give out, simultaneously. Emergence of false signals in SEAM is also analyzed on the bases of the upper surface of the sample earthed and the sample-transducer interface unearthed, the upper surface of the transducer earthed and the surface of the sample unearthed, and with both the upper surface of the sample and the transducer earthed. It would be best that the contrast switch is turned off when electron acoustic images are observed and imaged.