As a cathode material for lithium ion batteries, LiNiO₂ has various drawbacks such as difficulty to be
synthesized, poor cycling performance and poor thermal stability, which are all related to its crystal structure. Stared from the crystal structure,
this paper analyzed the causes that result in these drawbacks and reviewed the improve ways briefly. It was shown that just optimizing the synthesis
conditions could only improve the cycling performance to a degree. In order to overcome these drawbacks thoroughly, the most important thing is to
stabilize the layered structure of LiNiO₂ by part substitution of suitable elements for nickel or/and oxygen.

The development of vanadium oxides in lithium ion batteries was summaried. The structure, synthesis methods, electrochemical performances of V₂O₅, V_6
13, VO₂, V₃O₇ and V₆O₁₄ in lithium ion batteries were reviewed. The reasons for V₄O₉, V₂O₃ excluded from the application in lithium ion batteries were explained. Then the advantage and problem of vanadium oxides as cathode materials of lithium ion batteries were pointed out. Finally the authors considered that those vanadium oxides could be promising as cathode materials of lithium ion batteries.

The preparation, structure and properties of ferroelectric nanometer sized powders, nanocomposites, and nanoceramics were introduced. The change of structure and properties caused by the reduction
of particle size and pertinent mechanisms were discussed. Transparent nanocomposites were expected to be applied as the optical memories, optical computer, etc devices, while the nanoceramics can be
widely used to improve the characteristic parameters of current capacitors due to the greatly enhanced dielectric permittivity, breakdown voltage, ageing-resistivity, mechanical strength, etc. Better quality
of devices will be obtained by using the nanosized powders.

The spray pyrolysis technique is a wonderful method in material science. It possesses many advantages, such as low processing temperature, high homogeneity and purity of products, and so on. The key challenges of spray pyrolysis are control over the morphology and composition of product particles. It has been widely applied in the past few years. In this paper, the spray pyrolysis technique and the applications in production of ceramic powders, films, and fibers were briefly reviewed.

The shape of TiC can be octahedral, facet or/and non-facet dendrite in as-cast Titanium alloys. The growth
element and growth habit of TiC₆ in titanium alloys were analyzed with the theory of coordination polyhedron through directionally solidified
samples. The results indicate that the growth elements of TiC are TiC₆ with six coordinations. During the stacking of TiC₆ growth element, the
growth rates of families {100} and {111} are different, which may easily result in potential nuclei of octahedral TiC surrounded by {111}. During
the growing of TiC in the melt, the undercooling and composition at different part of the crystal’s surface vary significantly. Some quadratic dendrites
may appear in the direction of <100> and are characterized by facet growth resulting in facet dendritic TiC finally. If a large amount of
defects such as screw dislocation are foed on the slowly growing surface of TiC during the growth, the facet will disappear and non-facet dendritic
TiC will fo.

KAl(OH)₂CO₃ powders with different morphology were synthesized by the hy-drothermal method using AlCl₃·6H₂O, Al(NO₃)₃·6H₂O, Al₂(SO₄)₃·12H₂O as the precursors at 120℃ for 24h. The results show that Al(NO₃)₃·6H₂O is the best precursor for the synthesis of KAl(OH)₂CO₃. The KAl(OH)2CO₃ powder synthesized in the hydrothermal aqueous with NO₃^-concentration of 1.2mol/L possesses particle sizes of less than 20nm, slenderness ratio of less than 5 , and good size distribution.

(Y,Gd)₂O₃:Eu phosphors were prepared by the complex precipitation processing using the mixture of ammonium water
and ammonium hydrogen carbonate as complex precipitant. TG-DSC, FT-IR, XRD, SEM, TEM were used to characterize the as prepared
phosphors. The Eu₂O₃ concentration and calcining temperature have distinctly influence on the X-ray excited luminescence of the as prepared
powders. The resulted (Y,Gd)₂O₃:Eu powder calcined at 850℃ for 2h has an average particle size of 50nm. The specific surface area
of the weakly agglomerate powder is about 23m²/g. Its X-ray excited luminescence is much stronger than that of the powder prepared by oxalate
precipitation processing.

This study presents the manufacture of highly porous biological glass-ceramic with interconnected pores by adding porosifier, and its main
crystallized products are fluroapatite and wollastonite. The effects of preparation conditions involving porosifier deformation during pressing
(die-pressing technique), particle size and content, and forming pressure on the resultant porosity, pore size as well as structure and mechanical
properties were investigated. The experimental results demonstrate that the resultant porous glass-ceramic with a successful control of pore size
and 50%～82% volume fraction porosity can be obtained. Macropores with 250～850μm diameter forming through the pyrolysis of porosifier
interconnect through the holes with 50～300μm diameter in pore wall. Very little pore volume results from micropores with 2～4μm diameter
because of the incomplete sintering of glass particles. Due to plastic deformation under pressure, the green body that is added plastic porosifier
stearic acid is with high-strength and can be machined into complex shape, and the sintered products with flat-sphere shape macropores are with
high-strength also. On the contrast, because of elastic deformation of rigid porosifier polystyrene under pressure, green body is with low-strength
and can’t be machined, and the sintered products with round-sphere shape macropores are with low-strength also. The forming pressure has a strong impact on the properties of samples with plastic porosifier stearic acid,
but do not influence the properties of samples with rigid porosifier polystyrene significantly. The total porosity correlates with the weight content of
porosifier linearly, so the porosity and pore diameter can be controlled through controlling the porosifier size and its content. The compressive
strength increases with increased porosi

A four-blade geometry test fixture was used to capture the evolution moduli of alumina suspensions in gelcasting process in oscillatory measurement. The vane geometry was treated as a couette while
the test material moving with the blade formed cylinder-like shearing surface. The diameter of the cylinder was defined as effective diameter of vane and calibrated by comparing the complex modulus G*
with data from parallel plate in measuring polyacrylamide solution. Test results show that the effective diameter of the shearing cylinder is smaller than the diameter of the blades . This method provides an
convenient way to measure the sol-gel transition in gelcasting process.

The mechanical properties and microstructure of silicon nitride ceramics with MgO-Al₂O₃-SiO₂ as additives produced by pressless sintering
were investigated by XRD, SEM, TEM, EDS, and HRTEM. The relationship among preparation processing, microstructure, and mechanical properties was
emphatically discussed. Intensifying blend by planetary blender, silicon nitride ceramics sintered at 1780℃ for 3h has an uniform
microstructure with bigger aspect ratio of elongated grains (diameter in 0.3～0.8μm, length in 3～6μm, aspect ratio in 7～10),
flexure strength of 1.06GPa, HRA hardness of 92, H_v hardness of 14.2GPa, and fracture toughness of 6.6 MPa·m^0.5.

Abrasives as seeds were introduced to the starting materials of aluminium hydroxide by wet-grinding of high-purity alumina milling balls. The phase transformation from aluminium hydroxide to
α-Al₂O₃ was completed at 1100℃ for 2h by seeds added. The size of alumina particle derived from calcined aluminium hydroxide was
reduced and narrow particle size distribution was obtained with increasing amount of the seeds. Alumina grain shapes changed with the amount of introduced
seeds: equiaxed grains were observed for the samples without seeds introduction, hexagonal platelets were developed after seeds addition. Finally the grain
shape showed a trend to elongated grains with seed concentration up to 20wt%.

Nanometer NH₄Al(OH)₂CO₃ precursor was synthesized from NH₄Al(SO₄)₂ and NH₄HCO₃. The effect of α-Al₂O₃ seeds (-150nm) on the phase transformation and micrograph of alumina was studied. The results show that under the conditions of adding a small quantity of α-Al₂O₃ seeds, the nucleating temperature can be lowered, the transition rate enhanced effectivelly, the transition of Al₂O₃ from θ to α phase can be completed at a lower temperature, and the grain accumulation can also be influnced to a certain extent.

The layered LiNi_3/8Co_2/8Mn_3/8O_2-yF__y(y=0, 0.05, 0.10, 0.20) samples were prepared by using the co-precipitated hydroxide as precursor, and characterized by means of XRD,
XPS, SEM, cyclic voltammetry, charge/discharge tests, DSC etc techniques. The results show that fluorine doping can not induce the valence change of transition metal ions in LiNi_3/8Co_2/8Mn_3/8O_2-yF_y
samples. The samples with y=0.05, 0.10 show better cycling performance with no expense of capacity compared with undoped one, 97.5%, 96.2% capacity retention respectively after 30 cycles can be reached.
The c_h lattice expanding of samples with y=0.05, 0.10 reduces from 2.06% of undoped one to 1.017%, 1.018% respectively when lithium is de-intercalated, contributing to the improvement of structure stability
and electrochemical cycle character. However, the sample with y=0.20 exhibits lower capacity and faster capacity fading upon cycling, due to high cation disordering and internal impedance. Fluorine doping also
accelerates agglomeration of particles of the samples, enhancing operability of electrode preparation of the cathodes. In addition, fluorine-doped samples have better thermal stability than LiNi_3/8Co_2/8Mn_3/8O₂.

The morphology and microstructure of the electrodes under ultrasound were observed and analyzed by means of
ESEM and XRD. The effects of ultrasonic irradiation time on the electrochemical active surface of the Ti/SnO₂+Sb₂O₃/PbO₂ electrodes in 1.0mol/L
H₂SO₄ solutions were studied by cyclic voltammetry. The experimental results show that the ultrasound has the influence on the morphology and
microstructure of the electrodes surfaces. Under ultrasound for 20min, the cyclic voltammetric peak current density is about two times as high as that
of the anode without ultrasonic irradiation. The voltammetric charge of the electrodes increases firstly as the time under ultrasound increases, after
ultrasonic irradiation 20min, and the voltammetric charge decreases with increasing ultrasonic irradiation time. The voltammetric charge is the highest under the condition of ultrasonic irradiation for 20min, which
means that the electrochemical active surface of the electrodes is the largest at the ultrasonic irradiation time.

A semichemical method (SCM) was developed for synthesizing 0.80Pb(Mg_1/3Nb_2/3)O₃-0.20PbTiO₃ (PMNT) with pure perovskite phase. The influences of the chemical reactivities of the
partial starting materials, such as soluble Mg-salts instead of MgO, Pb-salts instead of PbO and Ti(OC₄H₉)₄ instead of TiO₂ and crystalline of pure perovskite phase of PMNT on the formation of perovskite
phase were investigated in detail. The influences of technological parameters, such as calcining temperature, sintering temperature and soaking time, on the phase content, and dielectric properties were investigated
systematically. The results show that Mg-salts are effective for the formation of perovskite phase, especially Mg(NO₃)₂ and/or Mg(AC)₂ instead of MgO in a molecular grade. Almost pure perovskite
phase can be obtained by both using Mg(NO₃)₂ and Ti(C₄H₉O)4 instead of MgO and TiO₂ respectively. The optimum preparation parameters are the calcining condition of 850℃/2h
and the sintering condition of 950℃/2h. The semichemical method has many advantages of not only simple preparation process, lowing calcining and sintering temperatures, shorting reacting time,
but also preparing ceramics with excellent dielectric properties. The sintered ceramics having clear crystal boundaries, large-sized crystal grains and high density, and pure perovskite phase of PMNT
were successfully prepared by the SCM.

Special compositions of Ba_0.7Sr_0.3·(1-y)TiO₃·yNb₂O₅ were designed for preparing the BSTN system by the traditional ceramic method. The composite ceramics in which
the two phases of the perovskite (BST) and the tungsten bronze (SBN) coexist were successfully prepared by this composition controlled in the excessiveness of some components. XRD and LCR
were used to measure the structure and dielectric constants of the composite ceramics. It is found that, in the perovskite (BST) structured system of BSTN ceramics, the second phase SBN starts to
appear when the excessive content of Nb₂O₅ is up to about 6mol%. Similarly, in the tungsten bronze (SBN) structured system, the second phase of BST can also begin to form while the excessive
content of (BaO+SrO) is up to about 11mol%. However, both the perovskite and the tungsten bronze phases formed in a system exhibit the different minorities of Nb₂O₅ and TiO₂ solved respectively
with changing the excessiveness. Especially in the case of the two phases being equivalent to each other in BSTN composite ceramics, Nb₂O₅ is hardly to be solved into the perovskite phase
due to shortage of Nb₂O₅ and excessiveness of TiO₂ in composition. However, a few of TiO₂ is easily to be solved in the tungsten bronze phase due to excessiveness of TiO₂.There
is a dual characteristic shown by the perovskite phase and the tungsten bronze phase in temperature dependence curve of dielectric constant in the BSTN. The Curie temperature of the tungsten bronze
phase decreases with the increase in solubility of TiO₂ in the phase structure. Conversely, the Curie temperature increases with increasing perovskite phase due to the primary effect of the tungsten
bronze phase being restricted by a lot of perovskite. The lowest transition temperature between ferroelectric and paraelectric phases in the BSTN is at about 200℃ and it is 90℃ lower than that
of the SBN without TiO₂ solved in the present work.

Ca_3-xSm_xCo₄O_9+δ(x=0, 0.15, 0.3 and 0.45) polycrystalline samples were prepared by using
sol-gel process followed by SPS sintering. Their thermoelectric properties were carefully studied from room temperature to 1000K. The substitution of
Sm for Ca results in the increase of both Seabeck coefficient and electrical resistivity, which could be attributed to the decrease of carrier concentrations.
The Sm substituted samples (x=0.15, 0.3) have lower thermal conductivity than Ca₃Co₄O_9+δ due to their lower electronic and lattice
thermal conductivities. The dimensionless figure of merit ZT reaches 0.3 at 1000K for the sample of Ca_2.7Sm_0.3Co₄O_9+δ.

La₂O₃-doped MoSi₂ was synthesized by self-propagating high-temperature synthesis. The morphology
of the combustion product was investigated by using scanning electron microscopy. The fracture toughness at room temperature was measured by Anstis’ mode
and the responded microstructure was analyzed by using SEM. The results show that the addition of La₂O₃ as a doping agent significantly
influences the thermodynamics and kinetics of combustion process when compared with the combustion synthesis of molybdenum disilicide alone.
The addition of La₂O₃ can obviously decrease the particle size of the combustion product, and the addition of La₂O₃ can obviously toughen the matrix.

Cu²⁺, La³⁺ and (Cu²⁺, La³⁺ ) co-doped BST ceramics were fabricated from the powder prepared by using barium nitrate, strontium nitrate, copper nitrate, lanthanum nitrate,tetra-n-butyl
titanate, and ammonium hydroxide via a citrate-nitrate combustion process. Pulse electric current sintering (PECS) was carried out to obtain the compact crystalline BST. The effects of Cu²⁺, La³⁺
doping and (Cu²⁺, La³⁺) co-doping on the dielectric property of BST were investigated. It showed that Cu²⁺, La³⁺ doping and (Cu²⁺, La³⁺) co-doping in BST bulk could dramatically
modify the homogeneous of grain sizes in the sintered samples. The dielectric test showed that the Cu doping decreased not only loss tangent, but also the dielectric constant, while La doping and (La, Cu)
co-doping decreased the loss tangent, but increased the dielectric constant at 25℃ to some degree.

Combustion synthesis of α-Si₃N₄ was carried out through a chemical activation method under controlled temperature. Temperature profile analysis
was carried out to determine the kinetics of combustion synthesis of α-Si₃N₄. The kinetic parameters included the combustion
wave velocity, the rate of temperature increase, the adiabatic temperature rise, the inert temperature rise time and the inert temperature decay
time, as well as the convention ratio of Si to Si₃N₄. Two methods, i. e., temperature profile analysis method and wave velocity method were
used to calculate the activation energy of combustion reaction of silicon in pressurized nitrogen. The kinetics analysis will provide guideline for
understanding the reaction mechanism and optimizing the processing parameters.

Mg is a modifier of Si--O network in sol-gel bioactive glasses, and Zinc is an essential trace element in human body
and has a stimulatory effect on bone formation. In this work, a CaO-SiO₂-P₂O₅ bioactive glass (58S) used as the based glass, Mg doped glass
(58S0.5M) and Zn doped glass (58S0.5Z) were prepared by the sol-gel technique , and the phase composition and the mechanical
strength of the glass cuboids were evaluated. In addition, the in vitro bioactivity of the glasses was tested by immersion in simulated body fluid
(SBF). The results indicated that 58S0.5M and 58S0.5Z were all amorphous even calcined at 800℃, and the incorporation of Mg and Zn improved
bending strength due to the higher bond energy of Mg--O and Zn--O as compared to Ca--O. The in vitro study showed that all glasses could induce hydroxyapatite
(HA) formation, but 58S0.5M and 58S0.5Z revealed a slower deposition of HA at the early stage of the immersion. After prolonged soaking, a thick layer of
HA was formed on all glasses, which suggested that Mg and Zn inhibited the HA nucleation at the early stage, but did not affect the deposition of HA in long
term soaking in SBF.

A novel BMP/α-TCP composite bone cement was developed by bone tissue engineering
approach. The releasing behavior of BMP from the composite was investigated in vitro through protein releasing testing, compressive
strength measurement and XRD analysis. With the help of histological study and X radiographic examination, the skull defect of rabbit was
repaired by the novel composite bone cement, and α-TCP bone cement was discussed as the control. Results in simulate body environment show
that the rules of BMP releasing from BMP/α-TCP composite agree with Higuchi equation, which indicate that BMP releasing accords with diffusion
model. The setting time of the bone cement is not influenced by the combination of BMP and α-TCP. After BMP releasing, the compressive
strength of materials increases with time, and the value reaches the level hardened pure α-TCP bone cement at fourth week. The crystalline
phase of materials is transferred into hydroxyapatite (HA) with time increasing. Animal experiments confirm the strong osteogenesis capacity of
the novel bone cement. Rabbit skull defect can be well healed with the materials in short period.

Eu³⁺ doped borate phosphors (SrB₄O₇, SrB₂O₄, Sr₂B₂O₅, Sr₃B₂O₆) were prepared by solid state reaction and sol-gel technique, respectively. The luminescent results showed that the four kinds of phosphors have different luminescent properties. The Sr₂B₂O₅:Eu³⁺, Sr₃B₂O₇:Eu³⁺ phosphors have the red emission at 610nm, the SrB₂O₄:Eu³⁺ phosphor has the orange emission at 593nm, however the SrB₄O₇:Eu³⁺ phosphor displays the emission peaks of Eu²⁺ ion, all that result from the different Eu-O coordination environment. The optimal doping concentration of phosphors is 2%.

Silica encapsulation was studied on the particle surface of aluminate-based luminescent pigment by using TEOS as
the raw materials. The encapsulated particles were analyzed by SEM, diameter testing, BET surface area measurement and XPS, a dense SiO₂ film formed
on particle surface with the thickness of 14nm. The anti-water property and luminescent characteristics measurement show
that encapsulated particles have a better anti-water performance and similar luminescent properties to non-encapsulated particles. Moreover, the
encapsulation procedure was analyzed and the process parameters’ effect on coating film was also researched. The results show that the encapsulation
procedure is actually a kind of sol-gel procedure of SiO₂·nH₂O on the surface of particles and its process is optimized as following: pH
of encapsulation solvent is about 10, encapsulation temperature is at 80℃ and reaction time is about 3.0.

Pillared montmorillonite (P-MMT), organic montmorillonite (O-MMT), layered double hydroxide (LDH) and layered double oxide (LDO) were prepared. Their adsorption performance on Cr (VI) was measured.
The result shows that adsorbent capability (AC) of P-MMT and O-MMT is 8.9 and 3.7 mg/g respectively; both of them can be attributed to physical adsorption. Their surface characters, i.e., hydrophilic P-MMT
versus hydrophobic O-MMT, are quite possibly responsible for the difference in AC. LDO’s AC on Cr (VI) is 73 mg/g at room temperature, much higher than that of the other materials. After the adsorption,
LDO’s XRD pattern changes apparently, similar to the one of LDH. This demonstrates that LDO took anions from the solution to recover the crystal structure of LDH, and that the adsorption is chemical
one. Theoretical AC of LDO on Cr (VI) calculated from the reaction formation is 152 mg/g. pH variation during the adsorption was observed. pH of the solution increased rapidly at the first few minutes,
slowly from 5 to 180 minute, decreased a bit after that. The first two phases indicate the adsorbing progress, and the last one is quite possibly related with the interference of dissolved CO₂. There
are two ways to restrain the activity of CO₂, increasing Cr (VI) content and/or decreasing CO₂ content. In the solution being boiled and isolated from air, LDO’s AC on Cr (VI) can be as high as 157.1 mg/g.
The part above the theoretical AC can regard as the contribution of physical adsorption.

Nano-structure TiN thin films with excellent properties were deposited on the silicon wafer and stainless steel substrate under room temperature by a filtered cathode
arc plasma technique. The structure and morphology of the films were characterized by atomic force microscopy (AFM) and small angle X-ray
diffractometer (XRD), and it’s hardness and elastic mouldness were measured by nano-indenter. Research results show that the TiN thin
films are highly uniform, very smooth, dense and droplet-phase-free. The average grain size of the films is 50nm, and it’s
hardness is up to 50GPa that is about two times of that deposited by conventional CVD and PVD techniques. XRD analysis demonstrates that the diffraction
peaks of the TiN films move to small angle, and the films display a preferred orientation along plane (111).

A precursor solution was prepared by dissolving nickel chloride salt and citric acid in butanol and ethanol. The solution was refluxed under continuous stirring and adding predetermined amount of water
(solution in solvent). The thin films were deposited by dip-coating methods. The thin films were analyzed by TG, DSC, TEM, SEM, XRD and cyclic voltammetry. The influence of heat treatment temperature on film transmittance
in the range of 350 nm to 850 nm was discussed. Results show that the thin film can transform from amorphous into cubic-NiO nanocrystalline by means of heat treatment. The results of cyclic voltammetry
of the films, carried out in an electrochemical cell with three electrodes and 0.1mol/L KOH electrolyte ,show that the NiO thin film treated at 350℃ for 30min has a good electrochromic performance. As given
voltage, the films reversibly change their colors from transparent to brown, and their transmittance can modulate from 80% to 30%. The cyclic voltammeter results also show that the film is quick to reach its
electrochromic stable condition.

TiO2 thin films synthesized from aqueous TiOSO₄ solution were characterized by X-ray diffractometry (XRD), atomic force microscopy (AFM) and UV-Vis transmittance measurements. The photoinduced hydrophilicity of the TiO₂ thin films was investigated. Results show that the as-synthesized TiO₂ thin films have good hydrophilicity; the hydrophilicity can be improved by increasing annealing temperatures at 100-500℃.

Aluminium nitride (AlN) powders were prepared by self-propagating high-temperature synthesis (SHS). Aluminium
and AlN powder mixtures with weight ratios of about 60/40, in the presence of 3wt% NH₄F and 3wt% carbon powders were ignited in a
nitrogen atmosphere of 8 MPa, resulting in highly crystalline AlN particles with regular hexagonal morphology. The microstructure development during the
reaction and the influence of additives of NH₄F and carbon were determined by SEM/EDS and XRD analysis of the resulting products. For the samples with
NH₄F and carbon, the combustion temperature could be kept on a high level for longer times compared to the sample without NH₄F and carbon. This
indicates that an after-burning phenomenon has occurred; Carbon apparently enhances vapour transport through a mechanism that involves reduction and
then removal of the surface oxide layer of the particles during after-burning.

Hollow superparamagnetic Fe₃O₄ nanospheres were prepared by co-precipitating iron (Ⅱ) and iron (Ⅲ) chloride salts in the presence of sodium hydroxide at 80℃. Triblock copoly-mer F127 was used as template. The nanospheres were characterized by XRD and TEM. The experimental results show that the Fe₃O₄ hollow nanospheres are uniform and well dispersed, the diameter is from 55 to 75nm and the shell thickness is about 7nm.

Semiconductor CdS nanorods were successfully synthesized by the hydrothermal method with monodentate
ligand methylamine as assistant. The obtained CdS nanorods were characterized by using TEM, XRD, Raman, and PL techniques respectively. Effects of the
concentration of methylamine on the morphologies of CdS nanocrystals were investigated. It was found that CdS nanocrystals synthesized displayed
nano-particle, short nanorod, and long nanorod shape when the concentration of methylamine was 1, 5, and 20wt% in the hydrothermal process, respectively.
This indicated that the type of ligand, i.e. bidentate or monodentate ligand, was not the critical factor for the formation of one dimention CdS nanocrystals
in the hydrothermal process. Based on the experimental results, a complex structure-controlling mechanism was proposed.

The absorption spectra and upconversion luminescence spectra of Er³⁺-doped oxyfluoride tellurite
glasses were investigated, and upconversion luminescence mechanisms of Er³⁺ in oxyfluoride tellurite glasses were analyzed. The results
show that the intense green (524 and 545nm) and red (655nm) emissions corresponding to the ²H_9/2→⁴I_15/2, ²H_11/2→⁴I_15/2,
⁴S_3/2→⁴I_15/2, and ⁴F_9/2→⁴I_15/2 transitions of Er³⁺ ions, respectively, can be simultaneously observed at room temperature under 975 nm diode laser excitation. With increasing PbF₂ concentrations, the intensity for the green emissions increases
slightly, while the red emission intensity enhances much larger than the green emission intensities. There are two basic upconversion mechanisms: excited state absorption and energy transfer, and a two-photon upconversion process is assigned to the intense green and
red emission, respectively.

The etching morphologies of TeO₂ crystal on (110) and (001) faces were observed by means of chemical etching and analyzed with the theory of symmetry group. The morphologies of etch pits are very special compared with the tetragonal system crystal with 422 point group. The morphologies of etch pits by theoretical analysis are in conformity with the experiment. It shows that the patterns of etch pits consist of {110} planes. It is clear that the habitual plane of TeO₂ crystal is {110} plane.

Gd₃Ga₅O₁₂ (GGG) precursor was synthesized by a co-precipitation method using ammonium
hydrogen carbonate as precipitator. TG-DTA and IR spectra indicated that the precursor was alkaline and the weight loss during calcination was
28.06%. The results of XRD analysis indicated that the polycrystalline powder was well-crystallized after calcination at 1000℃C for 3h.
Compared with the solid-state reaction, the carbonate co-precipitation had the merits of short reaction period, well-crystallization, low calcining
temperature, and less volatilization. As a result, the volatilization and disproportion of Gd₂O₃ and Ga₂O₃ could be well controlled
during crystal growth and the optical quality of single crystal was also improved.

Cr,Yb:YAG laser crystals codoped with 10 at% Yb and different concentration Cr were grown by the Czochralski
method. The absorption spectra, fluorescence spectra, and fluorescence lifetimes of Cr,Yb:YAG crystals were investigated at room temperature. With
the increase of Cr concentration in Cr,Yb:YAG crystals, the absorption coefficient at 1.03μm increases, and the fluorescence intensity and
lifetime decrease, the energy transfer efficiency from Yb³⁺ to Cr⁴⁺ increases and the quantum efficiency in Cr,Yb:YAG crystals decreases. The
optimum Cr concentration for Cr,Yb:YAG crystals was estimated.

The sintering of β-Si₃N₄ powder synthesized by self-propagating high-temperature synthesis was studied with the addition of MgO, Al₂O₃, Y₂O₃ as sintering additives. MgO was found to
be the effective sintering aids, and β-Si₃N₄ could be densified at 1600℃ under 20MPa with the addition of 10wt% MgO. XRD results showed that the additives did not react with β-Si3N4,
existing in glassy phase of the sintered sample, with the exception of Al₂O₃, which reacted with β-Si₃N₄ to form β -Sialon phase. The samples with MgO added had better mechanical properties
than that of samples doped with Y₂O₃ and Al₂O₃.

Nano Ti₅Si₃-TiC composites were in situ fabricated through spark plasma sintering (SPS) technique using Ti and SiC powders
without any additive. The phase constituent of the samples was analyzed by X-ray diffraction techniques and microstructures
were observed by scanning electron microscope and transmission electron microscope. The fracture toughness at room temperature
was also measured by indentation tests. The results show that the Ti₅Si₃-TiC composite can be fabricated by means of the
reactive sintering method in a relatively short time (8 min) and at a lower temperature (1260℃), with a fine microstructure (TiC grain size <200nm).

ZnO nano-powders were prepared by using microwave hydrolysis and constant temperature hydrolysis methods, using
Zn(CH₃COO)₂·2H₂O as the starting material. In order to improve gas sensitivities, ZnO nano-powders doped with Pt of Pd were also
prepared by using the microwave hydrolysis method. Their phase constitution and crystal structure were characterized by TEM and XRD analyses, and their
gas sensitivities were measured. results show that the microwave hydrolysis method is better than the canstant temperature hydrolysis method, for obtaining
ZnO nano-powders. The ZnO nanopowders prepared by using the two methods possess higher sensitivities to ethanol and gasoline, and the ZnO nanopowders doped
with Pt or Pd can enhance their selectivities to ethonal and gasoline, respectively.

A new method of surface treatment for austenitic stainless steel sheets was developed to improve their mechanical performance. An aluminium layer
was firstly formed on the surface of stainless steel by immersing the sheet into a 760℃ molten aluminium bath for 8 min. The aluminized stainless
steel sheet was then treated by micro-arc discharge oxidation. The structure of the resultant compound coating was analyzed by using X-ray diffraction,
scanning electron microscopy with energy dispersive spectrometer and Vickers micro-hardness tester. The results show that a ceramic coating composed mainly
of α-Al₂O₃ and γ-Al₂O₃ is formed on a medium intermetallic compound layer and the content of γ-Al₂O₃ is higher than that of α-Al₂O₃. The micro-hardness of the compound coating
shows a gradation from the coating surface (800HV) to the substrate (230HV) through the medium intermetallic compound layer (250～600HV).