Study on the mechanism of liquid phase sintering (M-12)

The objectives were to (1) obtain the data representing the growth rate of solid particles in a liquid matrix without the effect of gravity; and (2) reveal the growth behavior of solid particles during liquid phase sintering using the data obtained. Nickel and tungsten are used as the constituent materials in liquid phase sintering. The properties of the constituent metals are given. When a compact of the mixture of tungsten and nickel powders is heated and kept at 1550 C, nickel melts down but tungsten stays solid. As the density of tungsten is much greater than that of nickel, the sedimentation of tungsten particles occurs in the experiment on Earth. The difference between the experiments on Earth and in space is illustrated. The tungsten particles sink to the bottom and are brought into contact with each other. The resulting pressure at the contact point causes the accelerated dissolution of tungsten. Consequently, flat surfaces are formed at the contact sites. As a result of dissolution and reprecipitation of tungsten, the shape of particles changes to a polygon. This phenomenon is called 'flattening.' An example of flattening of tungsten particles is shown. Thus, the data obtained by the experiment on Earth may not represent the exact growth behavior of the solid particles in a liquid matrix. If the experiments were done in a microgravity environment, the data corresponding to the theoretical growth behavior of solid particles could be achieved

Photon and Pomeron -- induced production of Dijets in pppp, pApA and AAAA collisions

In this paper we present a detailed comparison of the dijet production by photon -- photon, photon -- pomeron and pomeron -- pomeron interactions in $pp$, $pA$ and ${\rm AA}$ collisions at the LHC energy. The transverse momentum, pseudo -- rapidity and angular dependencies of the cross sections are calculated at LHC energy using the Forward Physics Monte Carlo (FPMC), which allows to obtain realistic predictions for the dijet production with two leading intact hadrons. We obtain that \gamma \pom channel is dominant at forward rapidities in $pp$ collisions and in the full kinematical range in the nuclear collisions of heavy nuclei. Our results indicate that the analysis of dijet production at the LHC can be useful to test the Resolved Pomeron model as well as to constrain the magnitude of the absorption effects.Comment: 11 pages, 6 figures, 1 table. Improved and enlarged version published in European Physical Journal

Does the 8−N8-N bonding rule break down in As2_2Se3_3 glass?

The local coordination numbers of As$_2$Se$_3$ glass were determined by a combination of anomalous x-ray scattering experiments, reverse Monte Carlo calculations, and {\it ab initio} molecular dynamics simulations. The well-known `8-$N$ bonding rule' proposed by Mott breaks down around the As atoms, exceeding the rule by 7--26%. An experimental prediction based on mean-field theory agrees with the present experimental and theoretical results. The fourfold coordinated As atoms likely form As-As wrong bond chains rather than ethan-like configurations, which is identified as the origin for the breakdown of the `8-$N$ bonding rule'.Comment: 6 pages, 6figures, 1table, submitted to Europhysics Letter

In Situ Synchrotron Radiation Study of TiH2-6Al-4V and Ti-6Al-4V: Accelerated Alloying and Phase Transformation, and Formation of an Oxygen-Enriched Ti4Fe2O Phase in TiH2-6Al-4V

In situ heating, synchrotron radiation X-ray diffraction has been used to study the alloying and phase transformation behavior of TiH2-6Al-4V and Ti-6Al-4V alloys. Accelerated alloying and phase transformation were observed in the powder compact of the TiH2-6Al-4V alloy subjected to a high heating rate. In addition, an oxygen-stabilized Ti4Fe2O phase, which is present as sub-micron or nanoscaled particles, has been identified in the TiH2-6Al-4V alloy. The implications of these experimental findings have been discussed in terms of alloying, improved densification and oxygen scavenging in titanium and titanium alloys

Hepatitis C virus attenuates mitochondrial lipid β-oxidation by downregulating mitochondrial trifunctional-protein expression

The course of hepatitis C virus (HCV) infection and disease progression involves alterations in lipid metabolism, leading to symptoms such as hypocholesterolemia and steatosis. Steatosis can be induced by multiple mechanisms, including increases in lipid biosynthesis and uptake, impaired lipoprotein secretion, and/or attenuation of lipid β-oxidation. However, little is known about the effects of HCV on lipid β-oxidation. A previous proteomics study revealed that HCV interacted with both the α- and β-subunits of the mitochondrial trifunctional protein (MTP), an enzyme complex which catalyzes the last 3 steps of mitochondrial lipid β-oxidation for cellular energy production. Here we show that in HCV-infected Huh7.5 cells, lipid β-oxidation was significantly attenuated. Consistently with this, MTP protein and mRNA levels were suppressed by HCV infection. A loss-offunction study showed that MTP depletion rendered cells less responsive to alpha interferon (IFN-α) treatment by impairing IFN-stimulated gene expression. These aspects of host-virus interaction explain how HCV alters host energy homeostasis and how it may also contribute to the establishment of persistent infection in the liver

Nonet Symmetry and Two-Body Decays of Charmed Mesons

The decay of charmed mesons into pseudoscalar (P) and vector (V) mesons is studied in the context of nonet symmetry. We have found that it is badly broken in the PP channels and in the P sector of the PV channels as expected from the non-ideal mixing of the \eta and the \eta'. In the VV channels, it is also found that nonet symmetry does not describe the data well. We have found that this discrepancy cannot be attributed entirely to SU(3) breaking at the usual level of 20--30%. At least one, or both, of nonet and SU(3) symmetry must be very badly broken. The possibility of resolving the problem in the future is also discussed.Comment: 9 pages, UTAPHY-HEP-

Elastic ppˉ\rm{p\bar p} Scattering Amplitude at 1.8 TeV and Determination of Total Cross Section

The data on p$\mathrm{\bar p}$ elastic scattering at 1.8 and 1.96 TeV are analysed in terms of real and imaginary amplitudes, in a treatment with high accuracy, covering the whole t-range and satisfying the expectation of dispersion relation for amplitudes and for slopes. A method is introduced for determination of the total cross section and the other forward scattering parameters and to check compatibility of E-710, CDF and the recent D0 data. Slopes $B_R$ and $B_I$ of the real and imaginary amplitudes, treated as independent quantities, influence the amplitudes in the whole t-range and are important for the determination of the total cross section. The amplitudes are fully constructed, and a prediction is made of a marked dip in $d\sigma/dt$ in the $|t|$ range 3 - 5 GeV$^2$ due to the universal contribution of the process of three gluon exchange.Comment: 22 pages, 12 figures, 2 table

Comparative gene expression analysis of susceptible and resistant near-isogenic lines in common wheat infected by Puccinia triticina

Gene expression after leaf rust infection was compared in near-isogenic wheat lines differing in the Lr10 leaf rust resistance gene. RNA from susceptible and resistant plants was used for cDNA library construction. In total, 55 008 ESTs were sequenced from the two libraries, then combined and assembled into 14 268 unigenes for further analysis. Of these ESTs, 89% encoded proteins similar to (E value of < or =10(-5)) characterized or annotated proteins from the NCBI non-redundant database representing diverse molecular functions, cellular localization and biological processes based on gene ontology classification. Further, the unigenes were classified into susceptible and resistant classes based on the EST members assembled from the respective libraries. Several genes from the resistant sample (14-3-3 protein, wali5 protein, actin-depolymerization factor and ADP-ribosylation factor) and the susceptible sample (brown plant hopper resistance protein, caffeic acid O-methyltransferase, pathogenesis-related protein and senescence-associated protein) were selected and their differential expression in the resistant and susceptible samples collected at different time points after leaf rust infection was confirmed by RT-PCR analysis. The molecular pathogenicity of leaf rust in wheat was studied and the EST data generated made a foundation for future studies

SU(3)_flavor analysis of two-body weak decays of charmed baryons

We study two-body weak decays of charmed baryons \Lambda_c and \Xi_c into an octet or decuplet baryon and a pseudoscalar meson employing the SU(3) flavor symmetry. Using certain measured Cabibbo-favored modes, we fix the reduced amplitudes and predict the branching ratios of various decays of charmed baryons in the Cabibbo-enhanced, -suppressed and -doubly suppressed modes.Comment: 25 pages, No figure, Phys. Rev. D (to appear

The K2K SciBar Detector

A new near detector, SciBar, for the K2K long-baseline neutrino oscillation expe riment was installed to improve the measurement of neutrino energy spectrum and to study neutrino interactions in the energy region around 1 GeV. SciBar is a 'fully active' tracking detector with fine segmentation consisting of plastic scintillator bars. The detector was constructed in summer 2003 and is taking data since October 2003. The basic design and initial performance is presented.Comment: 7 pages, 4figures, Contributed to Proceedings of the 10th Vienna Conference on Instrumentation, Vienna, February 16-21, 200