F_R^A-模范畴中束积的几个性质

给出了ＦＡＲ－模范畴中束积的一个特征刻划和若干重要性质．

关于F^A_R—模范畴中束和与束积的几点注记

本文引进了FAR—模范畴中束和、束积的概念，给出了束和、束积的若干性质，并通过具体例子说明了FAR．—模范畴中的束和、束积与R—模范畴中束和、束积的某些差异．

Nonstationary sparsity-constrained seismic deconvolution

The Robinson convolution model is mainly restricted by three inappropriate assumptions, i.e., statistically white reflectivity, minimum-phase wavelet, and stationarity. Modern reflectivity inversion methods（e.g., sparsity-constrained deconvolution） generally attempt to suppress the problems associated with the first two assumptions but often ignore that seismic traces are nonstationary signals, which undermines the basic assumption of unchanging wavelet in reflectivity inversion. Through tests on reflectivity series, we confirm the effects of nonstationarity on reflectivity estimation and the loss of significant information, especially in deep layers. To overcome the problems caused by nonstationarity, we propose a nonstationary convolutional model, and then use the attenuation curve in log spectra to detect and correct the influences of nonstationarity. We use Gabor deconvolution to handle nonstationarity and sparsity-constrained deconvolution to separating reflectivity and wavelet. The combination of the two deconvolution methods effectively handles nonstationarity and greatly reduces the problems associated with the unreasonable assumptions regarding reflectivity and wavelet. Using marine seismic data, we show that correcting nonstationarity helps recover subtle reflectivity information and enhances the characterization of details with respect to the geological record.

Experimental analysis and application of sparsity constrained deconvolution

Sparsity constrained deconvolution can improve the resolution of band-limited seismic data compared to conventional deconvolution. However, such deconvolution methods result in nonunique solutions and suppress weak reflections. The Cauchy function, modified Cauchy function, and Huber function are commonly used constraint criteria in sparse deconvolution. We used numerical experiments to analyze the ability of sparsity constrained deconvolution to restore reflectivity sequences and protect weak reflections under different constraint criteria. The experimental results demonstrate that the performance of sparsity constrained deconvolution depends on the agreement between the constraint criteria and the probability distribution of the reflectivity sequences; furthermore, the modified Cauchy- constrained criterion protects the weak reflections better than the other criteria. Based on the model experiments, the probability distribution of the reflectivity sequences of carbonate and clastic formations is statistically analyzed by using well-logging data and then the modified Cauchy-constrained deconvolution is applied to real seismic data much improving the resolution.

Preparation of Tungsten Film and Its Tribological Properties under Boundary Lubrication Conditions

Tungsten film(W film) is deposited by using the ion beam assisted deposition(IBAD) on the 316 L substrate surface in this experiment. The micro structure and nano-hardness of the film are investigated by scanning electron microscopy(SEM) and nano-indentation tester. The tribological behavior of W film under lubrication by oil with ZDDP and MoDTC is evaluated by a SRV test machine. The tribo-film formed on the worn surfaces is investigated by X-ray photoelectron spectroscopy(XPS) to find out the tribological mechanisms between the W film and the two additional additives. The result shows that the W film lubricated by ZDDP and MoDTC-blended base oil has synergistic effects on the friction reduction property, while the anti-wear property is mainly caused by the hard surface of W film.

PHASE ANALYSES FOR DUAL ION BEAM DEPOSITED ZrO_2 FILMS ON NaCl SUBSTRATE

ZrO2 films on NaCl(100) substrate produced by oxygen ion bombardment and argon ion sputtering of Zr are analysed using TEM, XRD and XPS. The result of TEM shows that only cubic phase exists for the ZrO2 film produced by oxygen ion bombardment with 30μA/cm2 and 200eV, while the XRD result shows that there seems to exhibit a small quanitity of monoclinic phase apart from cubic one under the production condition of oxygen ion of 25μA/cm2, 100eV.

Morphology and fractal characteristic of deposits formed during fiber bundle media filtration

The scanning electronic microscope and automated image analyzer are adopted to investigate the morphology of deposits formed during fiber bundle media filtration, which results in the discovery of the self—similarity of the deposits. Then in this paper it is proposed that the deposits are a fractal structure. Moreover, the fractal dimension value is related to the filter performance. The higher the fractal dimension value, the higher the filtration efficiency, and the longer filtration cycle, but the development of the head loss is also faster.

Deposition of diamond like carbon films by using a single ion gun with varying beam source

Diamond like carbon films have been successfully deposited on the steel substrate, by using a single ion gun with varying beam source. The films may appear blue, yellow and transparent in color, which was found related to contaminants from the sample holder and could be avoided. The thickness of the films ranges from tens up to 200 nanometers, and the hardness is in the range 20 to 30 GPa. Raman analytical results reveal the films are in amorphous structure. The effects of different beam source on the films structure are further discussed.

Multichannel deconvolution with spatial refl ection regularization

Seismic deconvolution plays an important role in the seismic characterization of thin-layer structures and seismic resolution enhancement.However,the trace-by-trace processing strategy is applied and ignores the spatial connection along seismic traces,which gives the deconvolved result strong ambiguity and poor spatial continuity.To alleviate this issue,we developed a structurally constrained deconvolution algorithm.The proposed method extracts the refl ection structure characterization from the raw seismic data and introduces it to the multichannel deconvolution algorithm as a spatial refl ection regularization.Benefi ting from the introduction of the reflection regularization,the proposed method enhances the stability and spatial continuity of conventional deconvolution methods.Synthetic and field data examples confi rm the correctness and feasibility of the proposed method.

Thin film processing and multiferroic properties of Fe-BaTiO_3 hybrid composite

Multiferroic bi-layer Fe/BaTiO3 （BTO） thin films were successfully deposited on Pt（200）/MgO（100） substrates using ion beam sputter deposition （1BSD）, and the mutiferroic properties were studied at room temperature. X-ray diffraction （XRD） analyses showed that BTO films were c-axis oriented and epitaxially grown on platinum coated MgO substrates, and （110） epitaxial Fe films were subsequently grown on （001） BTO films. Fe/BTO bi-layer films showed good ferroelectric and ferromagnetic properties at room temperature and the multiferroic coupling was observed, which should be attributed to the hybridization of Fe and Ti occurring at the ferromagnetic-ferroelectric interface.

MoS_x FILMS DEPOSITED ON DIFFERENT MATRIXES BY ION BEAM TECHNIQUE

MoSx (x = 1.79 ￣ 2.34) films of 200 nm thickness are deposited onto brass and C20 steel substrates by the ion beam assisted technique, respectively. Structures and compositions of these films, and changes in valence states of the Mo element are examined by XRD and XPS before and after wear. The lubrication properties and wear resistances for two kinds of samples are evaluated using a pin-on-disk installation in atmosphere at the room temperature. Tribo-wear behaviours and the microstructures between two kinds of samples exhibit obvious differences.

A New Integrable Symplectic Map of Neumann Type

By resorting to the nonlinearization approach, a Neumann constraint associated with a discrete 3 × 3 matrix eigenvalue problem is considered. A new symplectic map of the Neumann type is obtained through nonlinearization of the discrete eigenvalue problem and its adjoint one. The generating function of integrals of motion is presented, by which the symplectic reap＇is further proved to be completely integrable in the Liouville sense.

Characterization of EBPVD micro-layer composites and simulation of its internal stress state

Based on the basic operating principal and the technology characteristic of electron beam physical vapor deposition(EBPVD) technique, EBPVD was used to prepare the micro-layer composites. The effect on the substrate preheating temperature was taken into accounts and the finite element analysis package ANSYS was used to simulate the internal stress field and the potential displacement changing tendency. The results show that one of the most important quality factors on the judgment of micro-layer composites is the adhesion between the substrate and the deposition layers as well as among the different deposition layers. Besides the existance of temperature gradient through the thickness of layers, the main reason for the internal stress in micro-layer composites is the mismatch of various properties of the layer and the substrate of different thermal expansions and crystal lattice types. With the increase of substrate preheating temperature, the inter-laminar shear stress also takes on a tendency of increase but the axial residual stress decrease.

An implicit symmetry constraint of the modified Korteweg-de Vries (mKdV) equation

In this paper, an implicit symmetry constraint is calculated and its associated binary nonlinearization of the Lax pairs and the adjoint Lax pairs is carried out for the modified Korteweg-de Vries (mKdV) equation. After introducing two new inde-pendent variables, we find that under the implicit symmetry constraint, the spatial part and the temporal part of the mKdV equation are decomposed into two finite-dimensional systems. Furthermore we prove that the obtained finite-dimensional systems are Hamiltonian systems and completely integrable in the Liouville sense.

Palladium-Carbon Composite Nanoparticle Films with Enhanced Electrocatalytic Activity for Hydrogen Peroxide Sensors

A nanocomposite electrocatalyst was prepared with the method of cluster beam deposition of palladium nanoparticle thin lms on carbon nanoparticle supporting layers and used as sensitive nonenzyme hydrogen peroxide sensors. An enhancement on the electrocatalytic activity of the palladium nanoparticles toward H2O2 reduction was observed, which was related to the coverage of the carbon nanoparticles. With one monolayer of carbon nanoparticles, the H2O2 detection sensitivity reached the maximum, which was more than twice of that of the pure Pd nanoparticles.

Effects of Ar ion assisted deposition on the optical and electrical characteristics of electron-beam-evaporated amorphous Si films

In this paper,the effects of Ar ion bombardment during the electron beam evaporation deposition of the amorphous Si film were investigated.It was found that the bombardment increases the light absorption by two to eleven times and increases the conductance of the film by 3 000 times.This has never been reported before of amorphous Si with electron beam evaporation deposition.

A Few Expanding Integrable Models, Hamiltonian Structures and Constrained Flows

Two kinds of higher-dimensional Lie algebras and their loop algebras are introduced, for which a few expanding integrable models including the coupling integrable couplings of the Broer-Kaup （BK） hierarchy and the dispersive long wave （DLW） hierarchy as well as the TB hierarchy are obtained. From the reductions of the coupling integrable couplings, the corresponding coupled integrable couplings of the BK equation, the DLW equation, and the TB equation are obtained, respectively. Especiaily, the coupling integrable coupling of the TB equation reduces to a few integrable couplings of the well-known mKdV equation. The Hamiltonian structures of the coupling integrable couplings of the three kinds of soliton hierarchies are worked out, respectively, by employing the variationai identity. Finally, we decompose the BK hierarchy of evolution equations into x-constrained flows and tn-eonstrained flows whose adjoint representations and the Lax pairs are given.

Area-corrected species richness patterns of vascular plants along a tropical elevational gradient

The relationship and elevation is a hot issue between species richness in ecology and has been documented extensively. It is widely accepted that area size can significantly affect this relationship and thus mask the effects of other predictors. Despite the importance of the relationship between species richness and elevation while accounting for the area effect, it is insufficiently studied. Here, we evaluated area-corrected species richness patterns of all vascular plants as well as six vascular plant subgroups （seed plants, ferns, trees, shrubs, herbs and vines） along a tropical elevational gradient （Hainan Island, China）. If assessed in equal-elevation bands, uncorrected species richness showed bell-shaped curves, while area-corrected species richness assessed in equal-area bands appeared to increase monotonically due to the small proportion of highlands on Hainan Island. The mid-domain effect （MDE） was significantly correlated with both uncorrected and area-corrected species richness. On Hainan Island, the use of equal-area elevational bands increased the explanatory power of MDE.These findings provide useful insights to adjust for the area effect and highlight the need to use equal- area bands along the elevational gradient.

Cold Light Mirror Fabricated by Electr on Beam Evaporation of TiO_2 and SiO_2

A process suitable for production on a large scale of cold light mirror for film projector is introduced. Deposition parameters required for producing TiO 2/SiO 2 optical multilayer systems by electron beam evaporation of TiO 2 and SiO 2 starting materials are investigated. Manufacture and techniques of cold mirror and the adhesion,stability, wear and corrosion resistance of cold mirror by this process are discussed. The result shows that cold mirror produced has good optical properties and better adhesion.

Chemical Composition and Mechanical Characteristic of Nitrogen Ion Beam Mixed Carbon Nanolayer

Ion beam methods for modification of nanohardness of surface nanolayers of the titanium alloy Ti6AI4V were applied. After deposition of carbon nanolayers by electron beam evaporation, the ion implantation of nitrogen into samples was carried out. The chemical composition of the modified surface area was investigated by AES （auger electron spectroscopy）. The nanohardness of resulted ion beam modified surface nanolayers were investigated by nanoindentation testing. The measured concentration profiles indicate the atomic mixing of carbon into the substrate. It was found that the modified samples had a markedly higher nanohardness than the unmodified samples. The increased nanohardness is attributed to the newly created phases in the surface area.