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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.
Diverse environmental conditions surrounding preimplantation embryos, including available nutrients, affect their metabolism and development in both short- and long-term manner. Thioredoxin-interacting protein (TXNIP) is a possible marker for preimplantation stress that is implicated in in vitro fertilization- (IVF) induced long-term DOHaD effects. B vitamins, as participants in one-carbon metabolism, may affect preimplantation embryos by epigenetic alterations of metabolically and developmentally important genes. In vitro-produced bovine embryos were cultured with or without Roswell Park Memorial Institute 1640 vitamin mixture, containing B vitamins and B vitamin-like substances, from day 3 after IVF and we evaluated blastocyst development and TXNIP messenger RNA (mRNA) expression in the blastocysts by reverse transcription-quantitative polymerase chain reaction. The degree of trimethylation of histone H3 lysine 27 (H3K27me3) at TXNIP promoter was examined semi-quantitatively by chromatin immunoprecipitation polymerase chain reaction. Total H3K27me3 were also compared between the groups by Western blot analysis. The vitamin treatment significantly increased the rates of blastocyst development (P<0.05) and their hatching (P<0.001) from the zona pellucida by day 8. The mRNA expression of TXNIP was lower (P<0.01) in blastocysts in the vitamin-mixture-treated group concomitant with higher (P<0.05) level of H3K27me3 of its promoter compared with the control group. The total H3K27me3 in the vitamin-mixture-treated group was also higher (P<0.01) than that in the control group. The epigenetic control of genes related to important metabolic processes during the periconceptional period by nutritional conditions in utero and/or in vitro may have possible implication for the developmental programming during this period that may impact the welfare and production traits of farm animals.
We compared the calculation performance of cosmological N-body simulations with and without GRAPE-4. A modified Barnes-Hut treecode was used for these simulations. GRAPE(GRAvity piPE) is a special-purpose computer for gravitational N-body simulations. The newest hardware GRAPE-4 achieved a quite high peak performance (1.08 Tflops). In cosmological N-body simulations, a large number of particles is required and fast algorithms such as Barnes-Hut treecode or P3M/PM are usually used. GRAPE-4 can accelearte such algorithms. In paticular, the PCI interface recently completed allows us to use fast host computer, thus it improved the performance of these fast algorithms. Figure 1 shows the CPU time per one timestep as functions of force calculation error for both systems with and without GRAPE-4.
Basic features of observed Type I X-ray bursts are thought to be interpreted in terms of helium shell-flash near the surface of the accreted neutron stars (Lewin and Joss 1981). Numerical models of the helium shell-flash show that the luminosity grows very close to the Eddingotn luminosity just after the peak of energy generation.
The electronic band structures of monolayer molybdenum dichalcogenides, MoS2, MoSe2, and MoTe2 under either uniaxial or biaxial strain are calculated using first-principles calculation with the GW method. The imposed uniaxial strain is in the zigzag direction in the honeycomb lattice whereas the imposed biaxial strain is in the zigzag and armchair directions. It is found that the band gaps of these dichalcogenides almost linearly increase with the decrease of the magnitude of compressive strain, reach their maxima at some compressive strain, and then decrease almost linearly with the increase of tensile strain. It is also found their maximum band gaps are direct bandgaps.
Using a self-assembly process, we fabricated ordered chains of transparent polystyrene microspheres that have 30°- and 60°-branched structures and that act as coupled-resonator optical waveguides (CROWs). We then observed the optical properties of propagation light through the CROWs. The light spectra were directly measured by guide-collection-mode near-field scanning optical microscopy (NSOM) techniques. The spectrum of light propagating to the 60°-branch shows some sharp peaks, which seem to be associated with whispering gallery modes (WGMs). On the other hand, the spectrum of light propagating to the 30°-branch shows rather broad peaks. Moreover, we observed the detailed structures of the CROWs by high-resolution scanning electron microscopy (HR-SEM), and performed a finite-difference time-domain (FDTD) simulation to explain the NSOM spectra. The results suggest that the microspheres’ branching chains themselves have a light-splitting function, which is a kind of wavelength-selective filter.
Since discovery of the Y-Ba-Cu oxide compound showing superconductivity above liquid nitrogen temperature, intensive study has been under way to clarify nature of the high Tc oxides[l-4]. Much efforts were also made in the field of superconductor applications. A number of studies have been carried out by a powder metallurgical process of Y-Ba-Cu oxide compound wires, although, obtained critical current densities were still low at liquid nitrogen temperature[5–6]. Other techniques for wire fabrication is also being attempted[7–9]. In this study, Y-Ba-Cu oxide superconducting composite tapes were prepared by a diffusion process, which is one of the promising methods to obtain a high critical current density.
Self-assembled silicon carbide (SiC) nano-dots were fabricated on Si wafers by an organometallic ion beam deposition. The self-assembled SiC nano-dots have the shape of a tile, and were heteroepitaxial SiC on Si.
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.
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.
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.
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.
A 32 Mbit chain FeRAM™ stack with 0.20μm minimum feature size was etched with two subsequent lithography/RIE steps: in mask step 1 the platinum/SRO (strontium ruthenium oxide) top electrode and the PZT (lead zirconate titanate) layer, in mask step 2 the bottom electrode together with the Ir/IrO2 diffusion barrier were etched. The stack was etched with various chlorine based chemistries. High temperature etching processes were applied to suppress residues by the formation of volatile etching byproducts resulting in a highly anisotropic etching profile and low redeposition.
Profile angles of 75° for step 1 and 80° for step 2 could be achieved. For the thin SRO-layer a separate etching recipe was developed to avoid surface roughening caused by micromasking. The influence of etching temperature and different gas chemistries on the etching behavior was evaluated. Reliable end point detection and good uniformity of the individual etching processes were obtained, both being crucial for the application of a multi-step recipe. The ferroelectric properties of the capacitor were confirmed by hysteresis measurements. This demonstrates that the ferroelectric properties were conserved during RIE etch processes at high temperature.
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.
Nanoparticul ate Pt50Ru50 supported on a carbon black (CB) were prepared by an impregnation method and the effect of the nano and microstructure towards the electrocatalytic oxidation of methanol and carbon monoxide were evaluated. The in-house prepared PtRu nanoparticles were well-alloyed and finely dispersed on CB, as revealed by XRD and FESEM. FESTEM-EDX analysis of isolated PtRu single nanoparticles indicated that although the majority of the binary particles had a metal composition in accordance to the nominal ratio, some compositional deviation was observed. The activity towards electrocatalytic oxidation of methanol and preadsorbed carbon monoxide is discussed based on the nano and microstructure.
The thermosetting mechanism of an organosilicon polymer containing carborane has been studied utilizing the 13and 29Si solid-state NMR method. The polymer having C≡C bonds in the main chain and CH═CH2, Si-H bonds, and carborane in the bulky side chain, shows a very highly thermal stability in air by curing. From 13C and 29Si NMR spectra of the polymer, it was found that the intermolecular cross-linking reactions of the polymer was due to (1) the diene reaction between Ph-C≡C and C≡C and (2) the addition reaction between side chain terminal and Ph-C≡C and between CH═CH2 and Si–H, and a very highly thermal stable structure is formed.
SiC thin films were formed on Si (111) at growth temperatures of 750–1000 °C using the molecular ion beam technique, with a precursor of methylsilicenium ions (SiCH3+). The chemical bindings and surface structures of SiC thin films were analyzed by Raman spectroscopy and reflection high-energy electron diffraction. As a result, 3C-SiC (111) was grown on Si (111) substrates without carbonized treatments.