Building a scientific and ecological earth–on an important field of geo-science:Geo-environment and construction engineering effect

This paper explores the 12 aspects of geo-environment and construction engineering, including the earth evolution, the structure of geological bodies, the comprehensive utilization of resources, the geo-environmental effect, the engineering construction, the sustainable development and, etc. This paper presents that the good environment could only be created through the conservation and efficient utilization of resources, the joint efforts of disaster prevention and mitigation, as well as the avoidance of adverse environmental effect caused by human activities. This paper concludes that, to build a scientific and ecological earth, the development laws of geo-science must be learnt.

Preparation of Rare Earth Doped Alumina Siloxane Gel and Its ER Effect

Poly(methyl methacrylate) (PMMA) was used to wrap alumina siloxane sol through emulsion polymerization. A kind of suspensions with notable ER effect was produced by fully mixing the prepared microcapsule with silicon oil. Meanwhile a series of PMMA wrapped alumina-siloxane gel doped with rare earths was obtained and its ER effect was tested, like viscosity of different rare earth ion doped samples in different powder concentrations and at different temperatures, at the same time, leak current density and dielectric constant were measured. Results show that the ER effect of this suspension is remarkable, and its stability is much better. The condition of emulsion polymerization and the mechanism of effect are discussed.

THE EFFECT OF RARE EARTH ELEMENTS ON THE SOLIDIFICATION BEHAVIOR OF Al-Mg ALLOYS

The effect of rare earth element on the solidification behavior of Al-Mg alloy was investigated in a directional solidification apparatus.It was found that during the solidification process.the rare earth element segregated in the liquid at sold-liquid interface,changed the solidification morphology and reduced the secondary arm spacing markedly.

Review of magnetic properties and magnetocaloric effect in the intermetallic compounds of rare earth with low boiling point metals

The magnetocaloric effect （MCE） in many rare earth （RE） based intermetallic compounds has been extensively in- vestigated during the last two decades, not only due to their potential applications for magnetic refrigeration but also for better understanding of the fundamental problems of the materials. This paper reviews our recent progress on studying the magnetic properties and MCE in some binary or ternary intermetallic compounds of RE with low boiling point metal（s） （Zn, Mg, and Cd）. Some of them exhibit promising MCE properties, which make them attractive for low temperature magnetic refrigeration. Characteristics of the magnetic transition, origin of large MCE, as well as the potential application of these compounds are thoroughly discussed. Additionally, a brief review of the magnetic and magnetocaloric properties in the quaternary rare earth nickel boroncarbides RENi2B2C superconductors is also presented.

Study on Inhibition Effects of Rare Earths on Superoxide Anion Radical by Using Pulse Radiolysis

The inhibition effect of rare earths on the production of ·O - 2 produced by radiolysis of aqueous sodium formate saturated with O 2 with high energy pulse electron beam was studied. The result indicates that rare earth nitrate obviously inhibits the production of ·O - 2 . The inhibition rate is between 28 6% and 92%. The inhibition effect increases with the increase of rare earth nitrates concentration. The distinguish dose effect relationship was observed.

RARE EARTH DISSOLVED IN SOLID SOLUTION OF STEEL AND ITS EFFECT ON MICROSTRUCTURE

The amounts of rare earth in the solid solution in steel 16Mn were determined by means of inductive coupling plasma(ICP)spectroscopy.While the RE/S ratio was less than 1.9,the amounts of rare earth in solid solution were not more than 8 ppm,which rised slightly with the increase of the rare earth content in the steel.While the RE/S was more than 1.9,MnS disappeared completely in the steel and the amounts of rare earth in solid solution increased rapidly with the increasing of the rare earth content.The solubility of cerium in steel 16 Mn(St 52)is less than 0.011 wt% at room temperature.The results also indicate that rare earth in solid solution can reduce the amount of pearlite and increase that of ferrite and its mierohardness.The rela- tionship between microhardness(Hv)and the amount of rare earth in solid solution can be expressed by the equation of Hv=117+7 RE(ppm).

Effect of Rare Earth Elements on Quantity Growth of Crops

The effects of rare earth on the growth of rice, rape and soybean in three kinds of soils were studied with the method supposed by Economic Co-operation and Development organization (OECD), and the EC50(median growth concentration)values were obtained. The inhibition of RE on the growth of rice and rape in red soil and on the growth of soybean in yellow fluvo-aquic soil is higher with stronger poison effects. Compared with other heavy metals such as Hg, Cd, Pb, As, the poison of RE on crops is weaker.

Preparation and Structure Characterization of Rare Earth Doped Alumina-Siloxane Gel and Its Modification on ER Effect

A series of samples of alumina-siloxane gel wrapped by poly (methyl methacrylate) and doped with rare earths such as lanthanum, praseodymium, yttrium, gadolinium and europium were prepared. The structure features were characterized by micrograph, X-ray fluorescence spectrum, X-ray diffraction spectrum, Fourier transform infrared spectrum and differential thermal analysis. Tests indicate that rare earths modify the electrorheological effects of the stable suspensions composed of samples stirred with silicon oil.

Physiological Effects of Rare Earths on Black Currant Plants

Various concentrations of ''Nongle'' rare earth were applied on 'Xinbin'' cultivar of black currant plants. The results indicated that leaf chlorophyll contents, photosynthetic rate, stomatal conductance, photon flux density and leaf transpiration rate of black currant plants were influenced significantly by rare earth applied on leaves. Foliage application of 300 to 800 mg/L rare earth two times in the growing season was better than those applied once.

Effects of rare earth metal addition on microstructure of hot-dip 55%Al-Zn-Si coatings

Optical microscope(OM),scanning electron microscope(SEM),energy dispersive spectrometer (EDS) and X-ray Diffraction(XRD) were used to study the effects of rare earth on the microstructural characteristics of 55%Al-Zn-1.6%Si hot -dip coatings on steel.The results of OM,SEM and EDS showed that by adding RE into the 55%Al-Zn-1.6%Si bath,the saw-toothed shape of intermetallic reaction layer of coating became smooth,and the thickness of the overlay and intermetallic reaction layer decreased.The XRD results revealed that the intermetallic reaction layer was comprised of two different regions,a bright phase closest to the steel substrate with phases of Fe_2Al_3 and a dark phase closest to the metallic coating with phases of FeAl_3/α-Fe-Al-Si.

EFFECTS OF RARE EARTH METAL ON HYDROGEN BEHAVIOUR IN STEEL 16Mn

The slow tensile tests,dynamic hydrogen charging tensile tests and hydrogen evolution tests after hydrogen charging were used to study the effects of rare earth metal(REM)on hydrogen behaviour in a steel 16Mn(St.52).The ratios of RE/S were chosen as 0,0.7,2.2 and 7.7,respectively.It was shown that the steel with RE/S = 2.2 give a lower hydrogen embrittlement susceptibility than others.The steels without REM can adsorb much more amount of hydrogen than that with REM under the same hydrogen charging conditions.And the amount of adsorbed hydrogen for the foriner can be evolved easier than that for the latter at room temperature,50℃ and 80℃,respectively.The experimental results were explained by the trap theory of hydrogen,the short-circuit diffusion paths in the interfaces between the elongated MnS inclusions and the matrix,and strong ability of REM to adsorb hydrogen.

Modifying Effect of Rare Earths and Titanium on Austenitic Manganese Steel

By means of thermodynamic calculations, optical microscope, sweep electron microscope(SEM), transimssion electron microscope(TEM) and microcomposition detection, the modifying effect of RE and Ti on austenitic manganese steel was investigated The results show that the constitutional supercooling of austenitic manganese steel during solidification can be improved and the dendritic crystals can be grown facilely, melted, isolated and multiplied by adding RE(Ce) In the melt the alloying elements Ti and C can form TiC directly which acts as nucleus of cementite and causes both primary and eutectic cementite to be granulated and refined so that the cementite network in this steel can be eliminated

Solvent Effects on Extraction of Rare Earth Metals with HDEHP

オhe extraction of Pr, Nd, Sm, Dy, Ho and Yb with HDEHP were studied in hexane, cyclohexane, carbon tetrachloride, toluene, benzene and chloroform at 298±1 K. The apparent and thermodynamic extraction equilibrium constants and the solubility parameters of the extraction complexes were obtained. The relationship between apparent equilibrium constants Kex and the physical parameters of solvents can be derived. The results indicated that the different solvents affect the apparent extraction equilibrium constants. The solubility parameters of the extraction complexes are nearly the same and not sensitive to rare earth ions.

Chemical Bond and Spectral Effect of Rare Earth Compound Crystals

The chemical bond parameters and ionic polarizabilities in complex crystals are calculated.The mechanism of host influence on the nephelauxetic effect and hypersensitive transition is discussed.

Rare Earth Doping Effects on Properties of Ceria-Zirconia Solid Solution

Ce0.6Zr0.3RE0.1O2(RE = Y, La, Pr, Tb)solid solutions were prepared by co-precipitation technique and characterized by a series of methods. XRD and FT-Raman results show that Ce0.6Zr0.3RE0.1O2 has cubic fluorite structure. The different dopant ion radii bring different effect on the cell parameter of Ce0.6Zr0.3RE0 1O2. The X-ray photoelectron spec-troscopy (XPS) results show that the binding energy of Ce3d, Zr3d and O1s for Ce0.6Zr0.3RE0.1O2 rises compared with that for Ce0.6Zr0.4O2, indicating that dopant elements change chemistry environment of solid solutions which is available to improve redox performance. Compared with Pd/Ce0.6Zr0.4O2, doping Y and La does not change air/fuel (A/F) characteristic of TWCs, but doping Pr and Tb widens A/F operating window and makes HC, CO and NO have higher conversion. The light-off temperature of Pd/Ce0.6Zr0.3La0.1O2 is corresponding to that of Pd/Ce0.6Zr0.4O2. However, the light-off temperatures of Pd/Ce0.6Zr0.3M0.1O2(M = Y, Pr, Tb) are lower than that of Pd/Ce0.6Zr0.4O2, which keep much lower after high temperature treatments. Among Pd/Ce0.6Zr0.3RE0.1 O2, Pd/Ce0.6Zr0.3Tb0.1 O2 represents wider A/F operating window, higher conversion, lower light-off temperature and better high-temperature resistance.

Alleviation Effects of Rare Earth on Cd Stress to Rape

Using rapes as test materials, the fastness expression and alleviation effect of rapes were studied under Cd stress condition, as the rapeseeds were dipped in the single element(La, Ce, Nd, Pr)and mixed rare earth(RE). The results indicate that, under Cd stress, the dry and fresh weight are increased by both the single element and mixed rare earth treatment, and the fastness of rape is improved.The single element of rare earth decreases the Cd content in rape roots and transmits Cd to the edible parts above the ground in which the alleviation effect of Ce is most significant.La treatment takes the second place, so that the poisonous effect of heavy metal Cd is eased.The mixed rare earth doesn't alleviate the assimilation of Cd in rape roots, but accelerates the transfer of Cd to the parts above the ground. The research puts forward that the alleviation of rare earth on Cd stress has connection with the decrease of Ca content.

Whitening Effect for Wool Processed by Rare Earth in the Dyeing Processes

The wool which were processed by rare earth in the dyeing processes have soft and loose hair withpure-white tone and silky luster. A few papers concerned with the mechanism of wool dyeing in the presenceof rare earth~[1,2]. However, the distribution of the combining of rare earth ions with wool toward the color andluster of woollen has not been discussed yet. In this paper, the whitening effect of Inner Mongolia goatwoolprocessed by rare earth after coarse wool were pulled out was investigated by electronic spectral ana-lysis. The wool samples including normal and rare earth processed Inner Mongolia goat wool were supplied

Hydrogen Fixation Effect of Rare Earths in Pure Aluminium and Aluminium Alloys

The areal distribution of some elements in the rare earth bearing spheroidal phases in pure aluminium and Al-Mn alloys was studied by SIMS(secondary ion mass spectrometry).The results show that cerium,iron. silicon and hydrogen are significantly segregated in the phases.Thus the existence of hydrogen-rich rare earth bearing eompounds is confirmed.It indicates that the rare earths have a hydrogen fixation effect in aluminium and aluminium alloys.

EFFECTS OF RARE EARTH ELEMENTS ON THE CHARACTERISTICS OF AUTO-TEMPERING AND DECOMPOSITION OF MARTENSITE FOR A LOW CARBON Si-Mn-V STEELS

The effect of rare earth metals(REM)on the characteristics of auto-tempering and decomposition of martensite for low-carbon and low-alloy steels(20SiMn2V and 20SiMn2VRE)was investigated using TEM,dilatometer and microhardness test.Results show that both ε.and θ carbides,during auto-tempering, may precipitate from the low-carbon martensite matrix at the same time in the 20SiMn2V steel,however,the precipitation of the ε-carbides can be inhibited by the REM contained in the 20SiMn2 VRE steel,resulting in change of the type of precipitated carbides and decrease of the extent of auto-tempering.The“in-situ”ob- servations show that the decomposition of martensite is also inhibited by the REM contained in the 20SiMn2 VRE steel during low temperature tempering.

Effects of Rare Earths on Properties and Microstructure of Automotive Friction Materials

Rare earth compounds as modifiers used widely in modern friction materials can enhance the interfacial binding of constituents of materials and improve the comprehensive properties of materials evidently. However, there are still few reports on application of rare earth in automotive friction materials. In order to study the effect mechanism of rare earths in friction materials, a rare earth compound was selected as additive and the effects of materials doped with or without rare earth on friction and wear properties of materials were studied. The microstructure and worn surface morphology were observed by scanning electron microscopy and the macro performance was discussed. Worn surface element constitution of materials was analyzed by energy dispersive spectroscopy. Effect mechanism of rare earths on friction and wear behaviors of friction materials were discussed. The results show that doping rare earths in friction materials can stabilize friction coefficient, lower the wear rate of materials and increase the impact strength of materials. The flexibility and fracture resistance of materials is greatly improved. Worn surface of materials doped with rare earth is compact and the surface adhesion is greatly enhanced.