STUDY ON MAGNETIC CHELATING RESIN Ⅰ.PREPARATI0N OF PEI2 AND ITS ADSORPTION PROPERTIES TO METAL IONS

Magnetic polyethyleneimine chelating resin(PEI2) was prepared. Its average diameter was 0. 44mm and it contained magneticparticles over 11% of the microcapsules after it had been treated with 8%hot HCl. The results showed that tbe reaction media had significant effecton Physical forms,magnetic particles content and stability in acid of themicrocapsules.PEI2 bad very high adsorption capacity to Au~(3+),Pb~(2+) andHg~(2+),and little one towards Mg~(2+),Pb~(2+) and Cu~(2+).It was discoveredthat PEI2 could reduce Au~(3+) into elemental gold.     

Characterization of YSZ Ceramic Nanopowders Synthesized at Different Temperatures via Polyacrylamide Gel Method

Tetragonal zirconia (T-ZrO_2) ceramic nanopowders stabilized with 3 mol% Y_2O_3 were synthesized via polyacrylamide gel method,using ZrOCl_2?8H_2O and Y(NO_3)_3?6H_2O as raw materials.The effect of temperature on phase composition and morphology of YSZ nanopowders and sintering behavior of YSZ ceramics was investigated by X-ray diffraction (XRD),scanning electron microscopy (SEM) and Vickers hardness tester.The aging-resistance of YSZ ceramics was measured by means of aging experiments.The results demonstrated that the phase composition of YSZ ceramic nanopowders had no obvious change and it was composed of T-ZrO_2.Particle size of well-dispersed YSZ ceramic nanopowders increased from 17 to 35 nm with increasing calcining temperature from 600 to 800 ℃.There was noticeable negative correlation between calcining temperature and the relative density of YSZ ceramic at the same sintering temperature.The aging experiments showed that water vapor facilitated tetragonal to monoclinic phase transformation,and the sample that had smaller grain size exhibited better aging-resistance.It can be concluded that when the calcining temperature is 600 ℃ and sintering temperature is 1 550 ℃,the relative density and hardness of YSZ ceramic arrive at the peak of 96.64% and 11.135 GPa respectively,and it has less microcracks and excellent aging-resistance.     

EFFECT OF METAL IONS ON ACTIVITY OF INTERLEUKIN-2

1 IntrodutionInterleukin-2(IL-2)was found to selectively keep growth of T lymphocytes for longperiod in vitro in 1976,and was then named T cell growth factor,TCGF.After that,IL-2 was found to promote proliferation of various cells,mainly including T,B,NK,and to in-crease activity of T cell and NK cell.Discovery of its surprising effect in treatment of can-cer,tumor through inducing LAK(lymphokine-activated killer cells)or activating TIL(tumor infiltrated lymphocytes)to kill cancer cell made it very attractive.Therefore it wasfound a wide application in therapy of cancer,immunodeficiency and diseases relating toinfection.However,in its application,problem was found that it had very serious side-effect,and very high dose made the side effect even more serious.The aim of this study was to find a simple way to stabilize IL-2 so as to lower the doserequired in application and in turn to solve the problem.     

Effect of Different Kinds of Zinc (Ⅱ) on Early Hydration of Calcium Aluminate Cement

The early hydration of calcium aluminate cement (CAC) with different kinds of zinc (II),such as ZnSO_4g7H_2O,ZnO,Zn(NO_3)_2·6H_2O and ZnCl_2,was analyzed.Changes in consistency,setting time,hydration heat flow,hydration heat amount,ion concentration in solution,and hydration products were found upon the addition of different Zn~(2+).The water consumption of standard consistency of CAC is decreased with different Zn~(2+).Zn~(2+) can delay the initial hydration of CAC.The induction period of cement with Zn~(2+) is longer than that of CAC,especially the reaction time of the acceleration period is extended.Zn~(2+) can promote hydration hydrate of CAC at 24 h.The characteristic diffraction peaks of CA and CA_2 in CAC with different Zn~(2+) are significantly reduced.It can inhibit the formation of CAH_(10 )and promote the formation C_3AH_6 and AH_3 in hydration products at 24 h.     

Effects of N Doping on the Microstructures and Optical Properties of TiO_2

TiO_2 nanopowders with different nitrogen(N) dopant concentrations were first synthesized by sol-gel method. XRD, TEM, HRTEM, XPS, UV-vis DRS were used to characterize the effects of N doping on the microstructures and optical properties of TiO_2. The results indicated that the prepared TiO_2 only contained anatase phase with a slight distortion, and the N doping improved the dispersity of TiO_2. The N doping leaded to more defects in TiO_2, capturing the charge carriers and inhibiting the combination of electrons and holes. Also, the N-doped TiO_2 was composed of Ti, O and N. Further, N was doped into the TiO_2 lattice by substituting for O, forming the oxidized nitrogen in the form of Ti–N–O or Ti–O–N bond, and Ti was present in the form of Ti~(4+) in TiO_2. Finally, the absorbance of N-doped TiO_2 was obviously improved in both UV and visible light region. Optical absorption edges of N-doped TiO_2 samples showed obvious red shift, which expanded spectral absorption range of TiO_2 and improved the utilization efficiency of visible light. It is concluded that N element was successfully doped into TiO_2 crystal lattice, and the N dopant concentration of 3.0% was designed to modify Ti O2.     

Metal chloride influence on syngas component during coal pyrolysis in fixed-bed and entrained flow drop-tube furnace

Pyrolysis was carried out in an entrained flow drop-tube furnace(DTF) and tube furnace(TF) using Pingzhuang lignite coal with various catalyst concentrations(2 wt%, 4 wt%, and 6 wt%) of KCl and CaCl_2 for the syngas component at 800°C–1200°C. Five catalysts(KCl, CaCl_2, NiCl_2, MnCl_2, and ZnCl_2) at 6 wt% were chosen for DTF at 800°C–1200°C. An online gas chromatograph analyzer and the Fourier transform infrared spectra were used for the analysis of the syngas and char structure. Results showed that the overall CO_2 and CH_4 content in DTF was lower than that in TF, mainly due to the CH_4 carbon reaction at high temperature. Moreover, the CO% in DTF was higher than in the TF experiment, as char reacts with carbon dioxide to form carbon monoxide. In DTF experiment, the maximum and minimum CO_2 content was 15.20% with 6 wt% Mn at 800°C and 0.33% with 6 wt% K at 1100°C, respectively. The maximum CO% was found in raw coal. Concentrations of Mn~(2+), Zn~(2+), and K+can significantly increase H2%, whereas Ca~(2+) and Ni~(2+) have a minor effect on H_2%; however, the overall presence of catalyst has a positive impact on the H_2 content.     

Influence of Rare Earth Co-dopant on the Photocatalytic Property of TiO_2 Nano-particles

A series of nanometer TiO2 photocatalysts co-doped respectively with rare earth Er3+-Ce3+ and La3+-Fe3+ were prepared by sol-gel method,and the photocatalytic activity under ultra-violet light was evaluated by photocatalytic degradation of methyl blue.The crystallographic forms,particles size,and morphology were characterized by XRD and TEM.The results showed that the optimum heat temperature of co-doped TiO2 was 550 ℃,and the co-doped TiO2 kept anatase.The anatase crystal had the average size of 20 nm.The co-doping caused red-shift of the UV-Vis absorption spectra and enhanced the absorption of light.Compared with the spectrum of pure TiO2 photocatalysts,the red-shift of Er3+-Ce3+ co-doping and La3+-Fe3+ co-doping catalysts was 53 nm and 34 nm,respectively.Optimal co-doping amount for Er3+-Ce3+ was n(Er3+):n(TiO2)=0.1%,n(Ce3+):(TiO2)= 0.05% and La3+-Fe3+ was n(La3+):n(TiO2)=0.05%,n(Fe3+):(TiO2)=0.5%.Under the condition the photocatalysis properties of the samples can be enhanced.It was found that the catalytic activity correlated well with the ratio.The degradation rate of methyl blue examined at two hour of the reaction was 92.37%,and the better photocatalysis properties than the non-doped TiO2 were obtained.The co-doped photocatalyst on methyl blue degradation follows the apparent first-order kinetics.     

Photoluminescence and cathodoluminescence properties of CaLaGa3O7：Eu3＋ phosphors

The CaLaGa3O7:Eu3+ phosphor was prepared by a chemical co-precipitation method.Field emission scanning electron microscopy(FE-SEM),laser particle size analysis,X-ray diffraction(XRD),photoluminescence(PL),and cathodoluminescence(CL) spectra were util-ized to characterize the synthesized phosphor.The results revealed that the phosphor was composed of microspheres with a slight agglomer-ate phenomenon and was spherically shaped.The average grain size was about 1.0 μm.Eu3+ ions,as luminescent centers,substituted La3+ ions into the single crystal lattice of CaLaGa3O7 with the sites of Cs.Although the CL spectrum was greatly different from the PL spec-trum,it had the strongest red emission corresponding to the 5D0 →7F2 transition of Eu3+.Under the excitation of UV light(287 nm) and elec-tron beams(1.0-7.0 kV),the chromaticity coordinates of the phosphor were found to be in the nearly red and orange light regions,respec-tively.     

A Modified Co-precipitation Method to Prepare Cu/ZnO/Al_2O_3 Catalyst and Its Application in Low Temperature Water-gas Shift(LT-WGS) Reaction

A modified co-precipitation method for the production of Cu/ZnO/Al_2O_3 complex was studied. The modification was that part of Al was introduced by adding Al~(3+) into Cu~(2+)/Zn~(2+) solution, and the rest of Al was added after co-precipitation step in the form of pseudo-boehmite. The prepared samples were characterized by different techniques such as X-ray diffraction, N_2 adsorption, H_2-N_2O titration, temperature programmed reduction and scanning electron microscopy. X-ray diffraction characterizations revealed that Al~(3+) can be doped in aurichalcite lattice, and the maximum doping amount of Al~(3+) was 5.0% of total Cu and Zn atoms. The Cu/ZnO/Al_2O_3 sample produced by the modified method, in which co-precipitated Al~(3+) was 2.5% of total Cu and Zn atoms showed much better activity and stability in water-gas shift reaction than commercial sample. The high Cu surface area(26.1 m~2/g) obtained by decompositon of doped aurichalcite is believed to be responsible for the activity enhancement. The stability was enhanced mainly because of the support effect of γ-Al_2O_3, which was decomposed from pseudo-boehmite in the calcination step.     

SURFACE CHEMICAL CHARACTERISTICS AND FLOATION SEPARATION OF WOLLASTONITE AND GARNET

In order to nealize the efficient floatation separation ofgarnet and wollastonite,the authors studied the surface chemical charac-teristics and various floatation behaviour of the two minerals,developedacidic combination depressant FD_1 and introduced sodium oleate,FeCl_3 andFD_1 as the flotation agent,they achieved success.In the experimental re-search on the artificiallymixed ores separation,the recovery and concentra-tion grade of the two minerals were both over 92% and 95% respectively.At the same time,it was found that the chemical absorption form of ironoleate presented bridge and chelating patterns on the surfaces of garnetand wollastonite activated by Fe~(3+).     

Flocculating Properties and Production of the Compound Bioflocculantby Rhizobium Radiobacter F2 and Bacillus Sphaeicus F6

A compound bioflocculant CBF,produced by mixed culture of Rhizobium radiobacter F2 and Bacillus sphaeicus F6, was investigated with regard to its production and flocculating properties. The optimization of the culture medium constituents including carbon source,nitrogen source and C / N ratio,metal ions and ionic strength on CBF production were studied. Flocculating properties of CBF were examined by a series of experiments and CBF had good flocculating activities in kaolin suspension with divalent cations and stable over wide range of p H. Studies of the flocculating properties revealed that the flocculation could be stimulated by cations Ca2+,Mg2+,Fe2+,Al3+and Fe3+. In addition,it was stable at 4-30 ℃ in the presence of Ca Cl2. It was found to be effective for flocculation of a kaolin suspension under neutral and weak alkaline conditions( p H 7. 0- 9. 0),and flocculating activities of higher than 95% were obtained when the CBF concentrations among 6- 14 mg / L at p H 8. 0. The results of this study indicate that CBF is a potential replacement of conventional synthetic flocculants and is widely applied in water treatment and downstream processing of food and fermentation industries.     

In Situ Growth of Vanadium Oxide on Reduced Graphene Oxide for the Low-Temperature NO-SCR by NH_3

The vanadium oxide/reduced graphene oxide(V_2 O_5/rGO) composite catalyst which determined the selective catalytic reduction activity(SCR) of NO with NH_3 was prepared by a simple solvothermal method. The physicochemical properties of the catalysts were characterized by X-ray diffraction(XRD), scanning electron microscopy(SEM), Raman, X-ray energy spectrometer(XPS) and N_2 sorption isotherm measurement(BET). Results of NH_3-SCR showed that the NO conversion of V_2 O_5/rGO catalyst could reach 54.3% at 100 ℃. And the removal of NO increased to 74.6% when the temperature was up to 220 ℃. By characterizing the microstructure and morphology of the V_2 O_5/rGO catalysts prepared by in-situ growth and mechanical mixing methods, it was further shown that V_2 O_5 nanoparticles were highly dispersed and in situ growth on the rGO surface. Based on X-ray energy spectrometer, V_2 O_5/r GO catalyst had good low temperature denitrification performance due to the chemical adsorption oxygen and low-valent vanadium oxide contained in V_2 O_5/rGO catalyst, which was beneficial to the redox reaction between V_2 O_5 and graphene.     

Mechanical properties and microstructure evolution of cold-deformed high-nitrogen nickelfree austenitic stainless steel during annealing

The mechanical properties and microstructure evolution of cold-deformed CrMnN austenitic stainless steel annealed in a temperature ranging from 50 ℃ to 650 ℃ for 90 min and at 550 ℃ for different time were investigated by tensile test, micro hardness test, and Transmission Electron Microscope (TEM). The steel was strengthened when it got annealed at temperatures ranging from 100 ℃ to 550 ℃, while it was softened when it got annealed at temperatures ranging from 550 ℃ to 650 ℃. Annealing temperature had stronger effect on mechanical properties than annealing time. TEM observations showed that nano-sized precipitates formed when the steel was annealed at 150 ℃ for 90 min, but the size and density of precipitates had no noticeable change with annealing temperature and time. Recrystallization occurred when the steel was annealed at temperatures above 550 ℃ for 90 min, and its scale increased with annealing temperature. Nano-sized annealing twins were observed. The mechanisms that controlled the mechanical behaviors of the steel were discussed.     

Crystallization and Luminescence Properties of Sm~(3+)-Doped SrO-Al_2O_3-SiO_2 Glass-Ceramics

The Sm~(3+)-doped SrO-Al_2O_3-SiO_2(SAS) glass-ceramics with excellent luminescence properties were prepared by batch melting and heat treatment. The crystallization behavior and luminescent properties of the glass-ceramics were investigated by DTA, XRD, SEM and luminescence spectroscopy. The results indicate that the crystal phase precipitated in this system is monocelsian(SrAl_2Si_2O_8) and with the increase of nucleation/crystallization temperature, the crystallite increases from 66 % to 79 %. The Sm~(3+)-doped SAS glass-ceramics emit green, orange and red lights centered at 565, 605, 650 and 715 nm under the excitation of 475 nm blue light which can be assigned to the 4 G5/2→6 Hj/2(j=5, 7, 9, 11) transitions ofSm~(3+), respectively. Besides, by increasing the crystallization temperature or the concentration ofSm~(3+), the emission lights of the samples located at 565, 605 and 650 nm are intensified significantly. The present results demonstrate that theSm~(3+)-doped SAS glassceramics are promising luminescence materials for white LED devices by fine controlling and combining of these three green, orange and red lights in appropriate proportion.     

Oxide transformation and break-up of liquid metal in boiling solutions

The non-toxic gallium-based liquid metals(LMs) are promising for various newly emerging areas due to having excellent fluidity, high electrical and heat conductivity. However, the oxide layers often affect their applications. In this paper, we disclosed a straightforward boiling strategy to efficiently remove the oxide of LM in deionized water. Meanwhile such method was also demonstrated to be capable of quickly breaking up LM into droplets(mean 0.51 mm, SD 0.20 mm) in Na Cl solution,which has important value for manufacture purpose. According to the force analysis, surface tension of LM dominates the interaction between solution bubbles and LM under the same heating conditions. Then we characterized the surface morphology and compositions of LM droplets boiled(LMDB) using scanning electron microscope(SEM), X-ray diffraction(XRD) and Xray photoelectron spectroscopy(XPS) and tested the dynamic force between a rod and LMDB. It was shown that after being boiled in water, most of Ga_2O_3 was transformed to scattered α-Ga OOH nanorods which has less restriction to the deformation of LM and large resistance force(0.8 mN) was tested; otherwise, after boiled in Na Cl solution, more Ga2 O3 with contact patch structure reduces the surface resistance of LM(0.2 m N) and makes it to be broken up by bubbles. The different surface products are determined by the inhibition of hydrolysis of Ga~(3+)by Na Cl solution. This study paved a simple way for oxide removal in neutral solution and mass production of LMD. It also suggests an efficient approach for exploring mechanisms of interactions between LM and bubbles, which is difficult to study otherwise in sonication.     

ON THE UTILIZATION OF BAUXITE OF POOR QUALITY

One kind of energy saving and high early strengthcement can be produced by using bauxite of poorquality which is refuse before. Through a series ofexperiments proper chemical compositions of the cementare obtained, and the cement clinker is sintered at alow temperature (1250℃) by the use of the bauxite tothe utmost limit. The results show, the cement notonly has high early strengths but also has a goodcharacteristic of resisting corrosion by sulphate.So it will be of great practical use. The hydraulicproperties of C_4 AF are always problematical, it isstudied again in this paper, showing that C_kAF hasgood hydraulic properties exactly; Cr~(3+), Ni~(3+) and Ti~(4+)can promote the formation of C_4AF and increase itsearly strengths; CaSO_4·2H_20 can also improve its 3days' strength but retard its hydration rate espe-cially in early ages.     

Preparation and characterization of high infrared emissivity Mn-doped NCO spinel composites

NiCr_2O_4(NCO)spinel composites with different Mn/Ni atomic ratios(Mn/Ni=0.05,0.10,0.15,and 0.20)were synthesized via solid state reaction method.Phase compositions and microstructure of samples were characterized by X-ray diffraction(XRD)and X-ray photoelectron spectroscopy(XPS).The TG-DSC curves showed that the appropriate baking temperature for Mn-doped NCO spinel preparation was approximately 1 320℃.X-ray diffraction patterns exhibited the formation of NCO spinel with Fd-3m space group.Valence state of the Mn ions was determined from 2p and 3s X-ray photoelectron spectra.Manganese ions were mostly in divalent and trivalent states,and the ratio of Mn~(2+)/Mn~(3+)was 0.78-0.98.Fourier transform infrared spectroscopy(FTIR)was used to analyze the spectral emissivity of Mn doped NCO spinel.It was revealed that the infrared emissivity of Mn-doped NCO spinel in 1.8-5μm could be significantly enhanced with increasing content of Mn~(2+),reaching as high as 0.9398.Mn-doped NCO spinel showed excellent radiation performance and good prospect in high emissivity applications in the temperature range of 800-1 200℃.     

Formation of Epitaxial Heavy-doped Silicon Films by PECVD Method

Plasma-enhanced CVD(PECVD) epitaxy at 200℃ was used to deposit heavy doped n-type silicon films. Post-annealing by rapid thermal processing was applied to improve the properties of the epitaxial layer. By analyzing the Raman spectra and the imaginary part of the dielectric constant spectra of the samples, it was found that high-quality heavy-doped epitaxial n-type silicon layer can be obtained by optimizing the parameters of the PECVD depositing process. Reducing the electrodes distance of the PECVD had a great effect on the crystallzation of the epitaxialed n-type silicon films. Sillicon films with high-crystallization were obtained with the electrodes distance of 18 mm. Post-annealing process can improve the crystallization and reduce the resistance of the epitaxial films. In our research, it was found that the sheet resistance(R_□) of the post-annealed films with thickness of about 50 nm has a simple relationship with RPH3/SiH_4(ratio of the flow rate of PH_3 and SiH_4) of the PECVD processing: R_□=-184-125 lg(R_(PH3/SiH4)). In the end, high-quality epitaxial n-type silicon film was obtained with R_□ of 15 Ω/□ and thickness of ~50 nm.     

INVESTIGATION OF MULTIPHASE-REINFORCED Si3N4 COMPOSITE MATERIAL

By means of whisker reinforce and paricle dispersion, the routes of property improvement on Si3N4 ceramic material have been studied. The mecihaniacl properties of Siw/Si3N4 and Siw/Si3N4TiC material was compared, which proved that multiphase reinforce had overlap effect. Microstructure of the material was investigated by means of SEM and the mechanisms of SiCw and TiCP reinforces had been disussed.     

Negative Thermal Expansion of (ZrMg)_xY_(2-2x)Mo_3O_(12) Ceramics with Low Hygroscopicity

(ZrMg)_xY_(2-2x)Mo_3O_(12)(x=0.0, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, and 1) ceramics have been synthesized to obtain less hygroscopicity and negative thermal expansion. With increasing the substitution of(ZrMg)~(6+) (ion radius 7.2 ×10~(-11) m) for Y~(3+) (ion radius 9×10~(-11) m), the crystal water are reduced obviously. The linear thermal expansion coefficient is improved with increasing the content of(ZrMg)~(6+). The material shows near zero thermal expansion(-0.12×10~(-6) K~(-1), 430-870 K) with x=0.7. Meanwhile, Zr Mg Mo_3O_(12) shows low non-hygroscopicity and negative thermal expansion, but low softening temperature. After substituting amount of Y~(3+) for(Zr Mg)~(6+) in Zr Mg Mo_3O_(12)(x=0.8), the softening temperature increases remarkably(750 K to 830 K) and it presents near zero thermal expansion.