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The present study investigated the dry matter yield (DMY) and arbuscular mycorrhizal (AM) colonization (internal hyphae, arbuscules, and vesicles) of two genotypes of zoysia grass (Zoysia japonica strain Aso and cv. Asagake) at three rates (10, 20 and 40 g N/m2/year) of application of digested slurry (DS) or mineral fertilizer. Soil chemical properties (available phosphorus concentration, pH and electrical conductivity (EC)) were also measured as factors associated with AM colonization. The fertilizer type (DS v. mineral fertilizer) had an effect on DMY depending on the plant genotypes but had little or no effect on AM colonization, and soil chemical properties, indicating that DS can be used as a substitute for mineral fertilizer; however, it is necessary to apply it taking into account the ratio of inorganic nitrogen (N). However, heavy DS application decreased colonization by internal hyphae. Furthermore, even at the lowest rate, the continuous application of DS decreased colonization by arbuscules and vesicles in both genotypes, which were associated with decreasing soil pH and increasing EC. The results suggest that zoysia grass should be fertilized with DS at a rate of <10 g N/m2/year in order to achieve a continuous association with AM fungi, although this range of N application is sub-optimal for zoysia grass production.
In most of globular clusters, surface abundance anomalies are observed not only from red giant stars but also from main sequence stars. We discuss the possibility that the latter anomalies can be explained in terms the pollution due to mass transfer during close encounters with red giants, the latter of which have already developed the anomalies through their internal processes. If this is the case, the main sequence stars with the abundance anomalies may serve as a probe into the star-star interactions in dense cores of globular clusters.
Equilibria of rigidly rotating polytropic gas with small compressibilities are computed in order to investigate the relation between the incompressible and compressible equilibria. The equilibrium figure varies from a spheroid-like shape to a concave hamburger as the angular velocity increases. This result is supported by the fact that a concave hamburger equilibrium is obtained even in the complete incompressible case. Thus the Maclaurin spheroid does not represent the incompressible limit of the rotating polytropic gas because of its restriction of the figure. The computed sequence of equilibria clarifies the relation between the Maclaurin spheroid and the Dyson-Wong toroid. Moreover it is the sequence of minimum-energy configuration. These results suggest that our solutions are more physical and probably stabler than any other equilibrium of incompressible fluids.
Cyclone–anticyclone asymmetry in spontaneous gravity wave radiation from a co-rotating vortex pair is investigated in an
-plane shallow water system. The far field of gravity waves is derived analytically by analogy with the theory of aeroacoustic sound wave radiation (Lighthill theory). In the derived form, the Earth’s rotation affects not only the propagation of gravity waves but also their source. While the results correspond to the theory of vortex sound in the limit of
, there is an asymmetry in gravity wave radiation between cyclone pairs and anticyclone pairs for finite values of
. Anticyclone pairs radiate gravity waves more intensely than cyclone pairs due to the effect of the Earth’s rotation. In addition, there is a local maximum of intensity of gravity waves from anticyclone pairs at an intermediate
. To verify the analytical solution, a numerical simulation is also performed with a newly developed spectral method in an unbounded domain. The novelty of this method is the absence of wave reflection at the boundary due to a conformal mapping and a pseudo-hyperviscosity that acts like a sponge layer in the far field of waves. The numerical results are in excellent agreement with the analytical results even for finite values of
for both cyclone pairs and anticyclone pairs.
For realizing the proof of mass production capablity or a move toward a GW/a production, 16%-efficiency project has been started setting the target of each parameter as V∝: 0.685 V/cell, FF: 0.735 and Jsc: 31.8mA/cm2. Up to FY2008, the target of each parameter independently has been achieved expect the efficiency. All of our research by adjusting the two resistance (Rsh and Rs) in the monolithically integrated 30cm×30cm-sized circuits. To improve the FF, double buffer structure with CBD-Zn(O,S,OH)x and MOCVD-ZnO is proposed and the thickness is adjusted by optimizing the Rs and the Rsh. As the result, FF of over 0.7 has been achieved for the first time in our CIS R&D since FY 1993.
Preparation processing to obtain 124 single phase films has been studied by MOCVD. The YBCO thin films which were fabricated on MgO(100) and SrTiO3(100) substrates, respectively, were obtained under both conditions of Ts(temperature of susceptor)=800°C and Po2(oxygen partial pressure)=17.5torr. It was found that the oriented peaks of 124 c-axis and of 123 a-axis were more prominent than others at the composition ratio(Y/Ba/Cu=l.0/2.7/4.7), using the MgO(100) substrates. The 123 a-axis oriented grain was observed by using SEM and TEM. We have obtained thin films which were dominant in the 124 phase on the SrTiO3(100) substrates. The film surface morphology on the SrTiO3(100) substrate was smoother than that on the MgO(100) substrate. The origin of a-axis oriented grain growth was explained by the surface step(about 10 À) on MgO(100).
Buried quantum well structures have been fabricated in GaAs/AIGaAs system using an in situ lithography process. The process utilizes an ultrathin oxide layer formed in situ on a GaAs surface as a mask against Cl2 gas etching. An electron beam (EB)-induced Cl2 gas etching is used to locally remove the oxide mask for positive-type lithography. For negativetype lithography, the oxide mask is selectively formed on a GaAs surface by EB-stimulated oxidation. Subsequent Cl2 gas etching results in the formation of isolated quantum wells. After removing the oxide mask, overgrowth using molecular beam epitaxy is successfully carried out on the patterned surface. The cathodoluminescence image of the buried quantum well demonstrates the high quality of the resulting structure formed by this “in situ EB lithography” process. The photoluminescence intensity from the quantum well of the processed sample is proved to be the same order of magnitude compared with that from a successively grown sample, showing that the use of the oxide mask causes no serious degradation in the processed interface.
The electron-donating [n]radialenes (n=3,4,5) were prepared with the aim of developing both new type of organic (super)conductors and unprecedented organic/molecular ferromagnets. The charge-transfer (CT) complexes of 1,3-dithioleradialene with TCNQ and of 1,3-benzodithiole-radialene with TCNQF4 and DDQ showed comparatively high electrical conductivities in compressed pellets. The single crystals of PF6 and CIO4 salts of 1,3-benzodithioleradialene radical cation revealed temperature change of electrical conductivity characteristic of a semiconductor. The magnetic properties of the bis(trifluoroacetate)salt of thioxanthene-radialene dication and of the CT complexes of 1,3-benzodithiole-radialene with DDQ, TCNQF4, and hexacyanohexamethylenecyclopropane, were also investigated from the ESR and/or magnetic susceptibility measurements.
Tris(l, 2-benzodithio)- and tris(l, 2-ethylenedithio)-trimethylenemethane dication salts were synthesized for the purpose of using as an acceptor in the formation of charge-transfer (CT) complexes with some dianionic donors. In the CT complexes of these dications with hexacyanotrimethylenecyclopropane and tetrafluorotetracyanoquinodimethane dianions, in which the CT degree is albeit small, the spin-spin interaction between the cation radical and the anion radical was antiferro magnetic in the temperature range of 60–293 K, but changed to a ferromagnetic one in the lower temperature range till 15 K, the lowest temperature used in this experiment. This provides the first demonstration of ferromagnetic spin-spin interaction in purely organic/molecular CT complexes. It is conceivable that the ferromagnetic spin-spin interaction is caused by a“spin polarization”mechanism rather than a“CT configurational mixing”mechanism.
In-situ patterning of AlxGa1-xAs (0≦x≦0.7) using a electron-beam (EB) and chlorine gas (Cl2) and the application to “In-Situ EB Lithography” are investigated. In this patterning method, an ultra-thin GaAs oxide is utilized as a resist film. The oxide resist prevents C12 gas etching of the underlying material and can be also patterned by an EB irradiation under a C12 pressure, which brings about selective etching of GaAs/AlGaAs layers. Etch rates of AlxGa1-xAs (0<x≦0.7) are 20-30 nm/min, which is almost equal to that of GaAs (20 nm/min). Using this technique of EB-induced patterning, a novel concept “In-Situ EB Lithography” is proposed, where the whole processes for EB lithography are successively conducted in a ultra-high vacuum multi-chamber system. An overgrown layer on a GaAs surface patterned by this “In-Situ EB Lithography” shows a good morphology.
The electrical properties associated with diamond charged particle- and photo-detectors were studied using charged particle-induced conductivity (CPIC) and photo-induced conductivity (PIC). The collection distance d, the product of the excess carrier mobility μ excess carrier lifetime T and electric field E, was used to characterize the diamonds. X-ray diffraction, Raman spectroscopy, photoluminescence, SEM and TEM were performed on CVD diamond detectors to investigate the limitations of the electrical properties. Correlations were found between the electrical properties and the material characterizations.
Two complementary techniques are used to study the electrical transport properties related to the use of diamonds as materials for ionizing radiation detectors. Transient photoconductivity using soft x-rays is used to probe the first few microns of the material, while ionizing particle-excited conductivity is used to probe the entire bulk of the material (1 millimeter). Both techniques measure the mean drift distance of free carriers, or the collection distance d. In addition, transient photoconductivity is able to extract the lifetimes and mobilities of the excited carriers. The collection distance measured by the two methods are in agreement, suggesting the material is homogeneous. At an applied field of 10 kV/cm, d is 25 to 30 microns, and, up to a field of 25 kV/cm, d has not saturated. The lifetime varies between 100 and 600 ps, and the mobility varies between 1000 and 4000 cm2/V-s, the range due to natural variations from sample to sample. The primary defects limiting the lifetime are believed to be nitrogen impurities and dislocations.
We synthesized the highly ordered mesoporous thin films with alkyltrimethyl-ammonium (CnTMA+). The arrangement of mesopores was depend on the Si/surfactant ratio. The hexagonal(P6mm) arrangement was observed, when Surfactant/Si ratio was 1/10. Increasing the Surfactant/Si ratio to 1.6/10, the cubic (Pm3n) arrangements were observed. A steel vessel for the measurement of the nitrogen adsorption isotherms of thin film on the substrate was designed. It was found that mesopore arrangements in the film is more regular than that in the powder samples prepared by the same acidic synthesis conditions.
The electrical properties associated with carrier mobility, μ, and lifetime, τ, have been investigated for the chemical vapor deposited (CVD) diamond films using charged particle-induced conductivity and time resolved transient photo-induced conductivity. The collection distance, d, the average distance which electron and hole depart when driven by an applied electric field E, was measured by both methods. The collection distance is related to the carrier mobility and lifetime by d = μEτ Our measurements show that the collection distance increases linearly with sample thickness for CVD diamond films. The collection distance at the growth side of the CVD diamond film is comparable to that of single crystal natural type IIa diamond; at the substrate side of the film, the collection distance is near zero. No saturation of the collection distance is observed for film thickness up to 500 microns.
Diamond is suitable for use as an ionizing particle detector for high rate, high radiation, and/or chemically harsh environments. A sampling calorimeter, a detector measuring the total energy of an incident particle, consisting of 20 alternating layers of diamond and tungsten has been constructed and tested. The diamond for the detector layers was grown by chemical vapor deposition with an averaged thickness of 500 μm. The active area of each layer was 3×3 cm2 with ohmic contacts on opposite faces forming a metal-insulator-metal structure. The calorimeter was tested with electrons of energies up to 5.0 GeV. The response of the diamond/tungsten calorimeter was found to be linear as a function of incident energy. A direct comparison of diamond/tungsten and silicon/tungsten calorimeters was made.
Polycrystalline samples of A1–xA'xNbO3 (A=Na+, K+; A'= La3+, Sr2+) were prepared by solid-state reactions and the relationship between the structure and electrical properties was examined. Single-phase products were obtained for Na1–xLaxNbO3 (x ≤0.1), K1–xLaxNbO3 (x ≤0.15), Na1–xSrxNbO3 (x ≤0.3), and K1–xSrxNbO3 (x ≤0.5). The structures of the sodium-containing compounds and potassium-containing compounds were indexed according to a pseudocubic and cubic symmetry, respectively. The resistivity measurements showed semiconductive behavior for the lanthanum-containing samples. The strontium-containing samples showed semiconducting properties for x ≤0.2, while a transition to metallic conduction at low temperature was observed for x >0.2.
Initial microstructure dependence of compactibility at elevated temperature in rapidly solidified Ti-rich TiAl alloy powders produced by plasma rotating electrode process (PREP) has been investigated. There were two kinds of powders with respect to the microstructure. The first one had a surface relief of a martensitic phase, which was referred as M powder. The second one had a dendritic structure, which was referred as D powder. α2+γ microduplex and α2/γ lamellar structures were formed in Mand D powders of the Ti-40 at%Al alloy by heat treatment at 1273 K, respectively. The microduplex structure consisted of γ precipitate in the twin related α2 matrix with the usual orientation relationship. It was difficult to compact the D powder by hot pressing at 1273 K under 50 MPa for 14.4 ks. On the other hand, the M powder was compacted easily by hot pressing with the same condition. The twin related α2 and α2 boundary changed to random ones and the α2 and γ phases were lost the usual orientation relationship in the duplex structure during the hot pressing. In other words, the low energy boundaries were changed to the high energy ones suitable for grain boundary sliding. Dislocations were scarcely observed inside of both the α2 and γ crystal grains. It was concluded that the grain boundary sliding was a predominant deformation mode in the M powder during the hot pressing. D and M powders in Ti-45 and 47 at%Al alloys showed the same tendency as those in Ti-40 at%Al alloy during hot pressing.
High quality Bi2O3 based Er-doped films for planar waveguide amplifier have been deposited by sputtering from sintered targets. It was found that both the amount of residual water and the Er concentration in films mainly affected a lifetime of the fluorescence at 1530nm. By optimizing these parameters, we have obtained films with a lifetime over 3msec, as the same as that of bulk glass prepared by the melting method.
For high density FeRAM devices small cell sizes are essential. The combination of the capacitor on plug (COP) structure with the Chain FeRAM™ cell design is used to develop a 32Mb FeRAM. Based on a 0.2 μm standard CMOS process a silicide capped polysilicon plug is used to contact the bottom electrode of the ferroelectric capacitor to the transistor. The barrier contact to the plug is formed by IrO2/Ir and a sputter deposited PZT (40/60) is used as ferroelectric material. The function of SrRuO3 (SRO) layers at the electrode/PZT interfaces is described in more detail. Double sided SRO results in slightly lower coercive voltage and imprint behavior compared to capacitors without SRO. Double sided SRO is essential to achieve excellent fatigue behavior measured up to 1×1011 switching cycles.
In this study, the pn hetero-interface between Zn(O,S,OH)x buffer and Cu(InGa)(SSe)2 (CIGSS) surface layers is discussed in order to achieve the fill factor (FF) over 0.73 and the circuit efficiency of 16 % on aperture area of over 800 cm2. Two resistances, i.e. shunt resistance (Rsh) and series resistance (Rs), in the circuits are employed as a yardstick to evaluate the interface quality. Since there are no realistic yardsticks on the Rs, the difference between Voc and optimum-power voltage (Vop) (i.e. Voc-Vop [V/cell]) is applied as a simple tool to evaluate the Rs. It is emphasized that it is important to reduce the Rs mainly correlated to the buffer deposition process and, as a result, the interface quality. We consider the Rs is dependent on the remaining Zn(OH)2 concentration in the Zn(O,S,OH)x buffer deposited by a chemical-bath deposition (CBD) technique. As an approach to make the Rs minimize and the Rsh maximize simultaneously, adjusting the thickness of a CBD-Zn(O,S,OH)x buffer layer and a non-doped ZnO layer deposited by a metal-organic chemical vapor deposition (MOCVD) technique has been effective to reduce the remaining Zn(OH)2 concentration. Determining the optimized deposition procedure to achieve the FF over 0.700 consistently, the circuit efficiency of 15.3 % with aperture area of 856 cm2 and the FF of 0.717 has been achieved.