FAST APPROXIMATE INVERSION OF MAGNETOTELLURIC(FAIMT) DATA FOR A HORIZONTALLY LAYERED EARTH WITH NEAR-SURFACE INHOMOGENEITIES

This paper discusses use of approximations and the Integral Mean Value Theorem to show that 6 coefficients approximately describe the distortions of near surface inhomogeneities on the MT field of a horizontally layered earth model. When these 6 coefficients are considered together with those of the magnetic field of a horizontally layered earth model,the analytic and approximate wave impedance equations can be derived for the MT response of a horizontally layered earth model with near-surface 2-D and 3-D inhomogeneities. These approximate wave impedance equations are used with inverted MT data for 2-D and 3-D forward modelling. Although these 6 coefficients cannot be determined before inversion,initial estimates can be used. The 6 coefficients and the asistivity and thickness of each layer of a horizontally layered earth can be obtained by using published inversion methods. The 6 coefficients give important informaion (depths and resistivities) on the near-surface inhomogenelties.The authors inverted 2-D and 3-D theoretical models for Fast Approximate Inversion of Magnetotelluric (FAIMT) data for a horizontally layered earth with near-surface inhomogeneities compares favorably with traditional invrsion methods, especially for inverting regional or basin structures. This method simplifies computation and gives a reasonable 1 -D geological model with fewer nonuniquenas problems.

Preparation and Characterization of Layered Compound Zirconium Bis(monohydrogenphosphate) Intercalated with Rare Earth Complex

Layered compound zirconium bis(monohydrogenphosphate)(alpha-ZrP) intercalated with rare earth complex Eu(DBM)(3)phen was prepared. The pre-intercalation of p-methoxyaniline into alpha-ZrP makes the interlayer separation large enough to exchange PMA with europium complex, thus, the luminescent assembly was prepared. This was confirmed by X-ray diffraction, UV-visible spectra and elemental analysis. The fluorescence spectra and lifetime of the assembly were also presented.

Numerical solutions of rotational normal modes of a triaxial two-layered anelastic Earth

The Earth's rotational normal modes depend on Earth model used, including the layer structures,principal inertia moments of different layers and the compliances. This study focuses on providing numerical solution of the rotational normal modes of a triaxial two-layered anelastic Earth model without external forces but with considering the complex forms of compliances and the electromagnetic coupling between the core and mantle. Based on the present knowledge of the Chandler wobble(CW) and Free Core Nutation(FCN), we provide a set of complete compliances which could be used for reference in further investigations. There are eight rotational normal mode solutions, four of which might exist in nature. However, in reality only two of these four solutions correspond to the present motion status of the prograde CW and the retrograde FCN. On one hand, our numerical calculations show that the periods and quality factors(Qs) of CW and FCN are respectively 434.90 and 429.86 mean solar days(d) and 76.56 and 23988.47 under frequency-dependent assumption, and the triaxiality prolongs CW about 0.01 d and has hardly effect on FCN. On the other hand, we analyze the sensibility of compliances and electromagnetic coupling parameter on the periods and Qs of CW and FCN and find the sensitive parameters with respect to them.

Dried earth layers of artificial forestland in the Loess Plateau of Shaanxi Province

By determining the earth moisture content of artificial forestland between 0 and 6 m deep in the Loess Plateau of Shaanxi province, the vertical change of moisture content, distribution and formation causes of a dried earth layer are researched. The results show that the average moisture content is 9.3%-9.5% between 2 and 4 m under artificial forest of over 10 year＇s growth in Guanzhong Plain, and chronic weak dried earth layers are developed which show that the dried earth layers are distributed extensively on the Loess Plateau. The southern boundary of the dried earth layer has reached the northern foot of the Qinling Mountains. When precipitation reaches 600 mm, there are weak dried earth layers between 2 and 4 m under artificial forest of more than 10 years old. When the precipitation is between 400 and 500 mm, there are moderate dried earth layers. When precipitation is above 800 mm, there are no dried earth layers. There are no dried earth layers under meadow land, corn land and less than 5 years old of artificial forestland in central and southern parts of the Loess Plateau. The development of dried earth layers under cypress forest is weaker than broad-leaved forest. Under the same climatic conditions, the development of dried earth layers under the loess tableland is nearly at the same level as the 2nd and 3rd river terrace. Dried earth layers developed in membrane water zone, and the buried depth is small and motion velocity is slow in the Loess Plateau, which is the direct water factor of the formation of the dried earth layer, while differences of tree age and tree species are the plant factors that consumed much moisture. From the depth of the gravity water and the membrane water in Guanzhong Plain, it is clear that the formation cause of dried earth layers is mainly due to natural factors. The dried layers generally develop in middle-aged artificial forestland that consumed too much moisture, which is the general character of earth moisture in subhumid and semiarid zones. The appearance of dried layers doesn＇t show that the forest doesn＇t develop in this area; this is depended on their development intensity. Artificial forest of Chinese poplar, locust tree and Chinese scholartree consuming less water can be planted in the areas where dried earth layer developed weakly, but can not be planted in the areas where dried earth layer developed intensely.

On Mechanism of The Effect of Rare Earth on Wearability of Nickel Base Self-Fluxing Alloy Spray-Welding Layers

The mechansim of the effect of rare earth(RE)on wearability of spray-welding layers has been investi- gated by adding RE in ppm into Nickel base self-fluxing alloy powder.The test results show that the microalloy- ing effect of RE can refine the structure of spray-welding layers,and change the amount,size,shape and distri- bution of hard phase in spray-welding layers.The wearability of spray-welding layers is increased consequently.

Synthesis and Property of H_2La_2Ti_3O_(10)/CdS Layered Nanocomposite Photocatalyst

H2La2Ti3O10/CdS nanocomposite with er photoactivity was synthesized by a stepwise exchange process from H2La2Ti3O10, which was obtained by H^＋ -exchanging reaction of H2La2Ti3O10 with HCl other than the normally used HNO3. The pillaring process was investigated by XRD, TEM, FT-IR and BET methods. The photocatalytic decomposition of aniline was used as the model system to evaluate the photochemical properties of H2La2Ti3O10/CdS,H2La2Ti3O10 and K2La2Ti3O10. It is found that the photoactivity of layered H2La2Ti3O10 is greatly improved by the intercalation of CdS in the interlayer. In general, the excellent photoactivity of the H2La2Ti3O10/CdS nanocomposite might be attributing to the extremely small particle size of incorporated CdS and good contact between CdS and La2Ti3O10^2- layers. On the other hand, the coupling of two semiconductor particles with different energy gap is useful to achieve effective charge separation. In H2La2Ti3O10/CdS, a photo-generated electron can transfer from CdS to the La2Ti3O10^2- layer, while the holes remain in the CdS particles. This helps to diffuse the electrons and holes before reaching the interface, and the holes and electrons can be effectively captured by the electrolyte in the solution. Simuhaneously, the optimal operating condition of photodecomposition aniline was investigated.

Structural and Electrical Properties of Layered Pervoskite Manganites Nd_(2-2x)Sr_(1+2x)Mn_2O_7 (x=0.25, 0.3, 0.4)

Tetragonally layered perovskite manganites of Nd2-2xSr1＋2xMn2O7（x =0.25, 0.3, 0.4） were fabricated by using solid-state reaction technique. Structural characterization of the compounds was investigated by X-ray diffraction （XRD） and FT-IR absorption spectra. The XRD patterns revealed that all the samples were single phase. X-ray photoemission spectroscopy （XPS） was used to investigate their electronic structures. It was found that manganese was in mixed states of Mn^3＋ and Mn^4＋ whereas lattice oxygen and chemical absorbed oxygen were existed in all the samples. The high temperature electrical properties of Nd2-2xSr1＋2xMn2O7 （x = 0.3, 0.4） were measured by standard four-probe technique. The results showed that both compounds had semi-conductivity behavior in the temperature range of 300 - 1073 K, and the electrical conduction was dominated by thermally activated behavior above 500 K.

High-Temperature Electric Properties and X-ray Photoemission Spectra of Layered Co-Based Oxides Bi_(2-x)La_xSr_2Co_2O_(8-δ)

Layered Co-based ceramics with a nominal composition Bi2-xLaxSr2Co2O8-δ (x=0.0, 0.4, 0.8, short by BLC-222) were prepared using conventional solid state reaction method. X-ray photoemission spectroscopy (XPS) was used to investigate their electronic structures. The cobalt ions are highly mixed valences of Co3+ and Co4+. The fraction of Co4+ almost keeps unchanged with the increase of x. The O-1s photoemission spectra show that there are lattice oxygen and chemical absorbed oxygen in all the samples. The substitution of Bi3+ by La3+ results in a change from metallic-like behavior to semiconductor behavior. This abnormal phenomenon means that La3+ plays a key role in effecting the electrical transport property of BLC-222. The O-Co covalence bond is strengthened by the increase of La3+, which results in the decrease of conductivity.

Influence of the earth rotation on the interfacial wave solutions and wave-induced tangential stress in a two-layer fluid system

Interfacial waves and wave-induced tangential stress are studied for geostrophic small amplitude waves of two-layer fluid with a top free surface and a fiat bottom. The solutions were deduced from the general form of linear fluid dynamic equations of two-layer fluid under the f-plane approximation, and wave-induced tangential stress were estimated based on the solutions obtained. As expected, the solutions derived from the present work include as special cases those obtained by Sun et al. （2004. Science in China, Ser. D, 47（12）： 1147-1154） for geostrophic small amplitude surface wave solutions and wave-induced tangential stress if the density of the upper layer is much smaller than that of the lower layer. The results show that the interface and the surface will oscillate synchronously, and the influence of the earth＇s rotation both on the surface wave solutions and the interfacial wave solutions should be considered.

Analysis of Valence Electron Structure in Compound Layer of Steel 42CrMo Plasma Nitrided with Rare Earth Addition

The valence electron structure (VES) in compound layer of steel plasma-nitrided at 560°C with rare earth (RE) addition was calculated based on the empirical electron theory (EET) of solids and molecules and BLD method. The results show that the presence of RE atoms diffused into surface layer leads to an increase of phase structure factor, which explains the catalyzing and micro-alloying effects of RE.

Study of Physicochemical Properties and Active Oxygen in Structures ofLayered Mixed La_(4)BaCu_(5-x)MxO_(13+λ)(M=Mn,Co)

Two series of layered mixed oxides La4BaCu5-xMxO13+(M=Mn, Co, x=05) were prepared and characterized by means of XRD, XPS, O2TPD and chemical analysis. The results show that their structures are 5layered ABO3 perovskite, and the XPS and O2TPD investigation confirms that there exists synergistic effect between Cu ion and M when M ion is doped into the lattice of La4BaCu5O13+, and the synergistic effect between Mn and Cu is stronger than that of CuCo.

Microstructure and Element Profile of Rare Earth Permeating Layer of Al Bronze

Rare earth (RE) atoms were permeated into the surface of Al bronze (Cu-7. gA1-1. 9 Sn) by the method of chemical heat treatment. The permeated layer was then analysed by TEM (Transmission Electron Microscope) , EPMA (Electronic Probe Microanalysis) and IMA (Ion Microprobe Appratus). The results show that CuREAl and dispersed η phase (Cu6Sn5) distribute in the layer, RE content decreases in the depth direction, and alloying elements (Al, Sn) are enriched in the outer layer and dilute in the second layer.

Layer Structure Analysis of Low-Carbon Steel Containing Rare Earth by High-Temperature Carburizing of Liquid Cast-Iron

The layer structure of low-carbon steel containing RE by high-temperature (T>1200 ℃) carburizing of liquid cast-iron was studied and the diffusion activation energy of carbon was calculated by metallographic microscpe, chemical analysis etc. The result shows that the technology of carburizing in liquid cast-iron can expedite caburization distinctly and changes the carburizing layer structure. The carburizing rate is 60～80 times of that of the traditional technology, and there is about 43% decrease in the activation energy compared with gas-carburization. In outer structure layer, cementite is formed simultaneously both on the crystal boundary reticularly and inside the crystal grains stripedly. In inner carburizing layer, there is undissolved blocky ferrite in reticular cementite. Besides, rare earth element can expedite carburization process.

Effect of Rare Earth on theFormation of Liquid ZincCorrosion ResistantChromium-carbide Layer

The effect of rareearth reducing agent on the thickness of layer and properties of bathduring the forming process of liquidzinc corrosion resistant chromiumcarbide layer through the thermalreaction deposition and diffusionmethod was studied. The resultsshow that the addition of 8%RE-SiFe-Mg can make the borax systemwith 15% Cr2O3 have better chromium-carbide layer-formation abilityand excellent technical propertiesthan those of Al or Si at 950 ℃.

New U-Pb and Sm-Nd Data and REE Distribution in Sulphides of Paleoproterozoic PGE Layered Intrusions in the Arctic Part of the Fennoscandian Shield

The U-Pb (on zircon) and Sm-Nd analysis is a popular isotope-geochronological tool for estimating the age of rocks from PGE mafic-ultramafic intrusions. Sulphides can be used to study the geochronology of ore processes as well, since they should indicate the time of ore mineralization. Gabbronorite has been sampled from the Passivaara reef at the Penikat layered intrusion (Finland) for U-Pb and Sm-Nd isotope single zircon analyses in order to separate sulphide minerals. The Sm-Nd isotope age of gabbronorite has been dated at 2426 ± 36 Ma;eNd(T) = −1.4 ± 0.4. The Sm-Nd isotope age on sulphides and rock-forming minerals reflects the crystallization time of the ore-bearing gabbronorite from the Passivaara reef of the Penikat layered intrusion. The mass-spectrometer analytical environment and modes of operation have been adjusted to detect REE in sulphide minerals on example of pyrite from the PGE Penikat layered intrusion (Finland) and chalcopyrite from the Talnakh deposit (Norilsk area, Russia) has been estimated. The total REE content in pyrite is ca. 3.5 ppm, which is enough to define the Sm-Nd age of pyrite. The study shows how to use the mineral/chondrite spectra to evaluate the accuracy of the REE analytical results on example of State Standard Sample 2463 (Russia).

Synthesis of PMA/Eu_2O_3 porous-layered nanocomposite by in situ polymerization and its morphology

The PMA/Eu2O3 porous and layered nanocomposite was prepared by in situ polymerization and characterized by means of X-ray diffraction （XRD）, transmission electron microscopy （TEM）, scanning electron microscope （SEM）, and inflared ray （IR）. Microscopic investigation of the nanocomposite was carded out by atomic force microscopy （AFM）. The results showed that the shape of the composite was layered and porous. Eu2O3 was grafted when methyl acrylate （MA） polymerized; thus Eu2O3 particles appeared on both sides of the chains of polymeric methyl acrylate （PMA）.

Phase Behavior of Rare Earth Manganites

Among complex oxides containing rare earth and manganese BaLn_2Mn_2O_7 (Ln=rare earth) with the layered perovskite type and Ln_2(Mn, M)O_7 with pyrochlore-related structure were studied since these compounds show many kinds of phases and unique phase transitions. In BaLn_2Mn_2O_7 there appear many phases, depending on the synthetic conditions for each rare earth. The tetragonal phase of so-called Ruddlesden-Popper type is the fundamental structure and many kinds of deformed modification of this structure are obtained. For BaEu_2Mn_2O_7 at least five phases have been identified from the results of X-ray diffraction analysis with the space group P4_2/mnm, Fmmm, Immm and A2/m in addition to the fundamental tetragonal I4/mmm phase. In the pyrochlore-related type compounds, Ln_2Mn_(2-x)M_xO_7 (M=Ta, Nb, W etc), there also appear several phases with different crystal structures. With regard to every rare earth, Ln_2MnTaO_7 phase is stable only for excess Ta and can be obtained under high oxygen partial pressure process. This group has trigonal structure with zirkelite type (P3_121 space group). On the other hand Ln_2Mn_(2/3)Nb_(4/3)O_7 phase has monoclinic (C2/c space group) and zirconolite type structure. All of these structural models have the fundamental structure based on HTB (hexagonal tungsten bronze) layers formed by the arrangement of oxygen octahedra.

Fabricating Buffer Layers for YBa_2Cu_3O_y Coated Conductor by Surface Oxidation Epitaxy

NiO buffer layers were formed on a tape of Ni for making YBCO coated conductor by surface-oxidation epitaxy （SOE） process. Different oxidizing conditions such as temperature and duration were studied for Ni tapes. It is found that the texture of NiO could be affected directly by the orientation and surface of substrate. X-ray diffraction （XRD） 2-2θ scan, φ-scan, and pole figure were employed to characterize the in-plane alignment and cube texture. X-ray φ-scan shows that NiO film is formed on Ni tape with high cube texture and a typical value at the full width at half maximum （FWHM） is ≤ 7.5°. Scanning electron microscopy was used to study the surface morphology of NiO films. No crack is found and the films appear dense. Such technique is simple and of low cost with perfect reproducibility, promising for developing long tapes.

Self-Assembled Film of Tb^(3+) and Poly(3- Thiophene Acetic Acid) via Layer-by-Layer Complexation Technique and Its Photoluminescence

The layer by layer complexation technique of polymer and metal ion was successfully utilized to fabricate the ultrathin multilayer film of poly(3 thiophene acetic acid (PTAA) and Tb 3+ ion by dipping the substrates alternatively in polymer and Tb 3+ ion aqueous solutions. UV-vis measurement revealed that the absorbance has linearity with the bilayer number from layer to layer and the X ray photoelectron spectrum (XPS) confirmed the existence of Tb 3+ ion. The pH of both the polymer and TbCl 3 solutions influence the thickness dramatically while the concentration of the solutions is not so sensitive. The luminescent spectrum of the complex film shows the characteristic emission of Tb 3+ ion as well as the ligand indicating the formation of the complex.

Crystal Structure and Luminescence Spectra of Novel Coordination Layer of {[Eu(m-BDC)(NO_3)(Phen)(H_2O)]_2·2CH_3CH_2OH}_n

The crystal structure of a novel Eu^(3+) coordination polymer, {[Eu(m-BDC)(NO_3)(Phen)(H_2O)]_2·2CH_3CH_2OH}_n (m-BDC=1,3-benzenedicarboxylate, Phen=1, 10-phenanthroline), was obtained and its high-resolution luminescence spectra at 77K were measured. The μ_2-carboxylate of m-BDC constructs the binuclear building block in which each Eu^(3+) ion is coordinated by four oxygen atoms of m-BDC anions, one oxygen atom from water molecule, two oxygen atoms of nitrate and two nitrogen atoms of Phen, respectively. The μ_1-carboxylate of m-BDC conjugates the binuclear units one-dimensional chain or a ribbon, while the hydrogen bonds between ribbons assemble the structure two-dimensional layer with a thickness equaling to the width of the ribbon. The luminescence spectra reveal that the two Eu^(3+) ion sites in the binuclear building blocks have slight environmental difference. The C_1 local symmetry of Eu^(3+) ion is concluded from both crystal structure measurement and luminescence spectra.