Measurement of Strain-Amplitude Dependent Internal Friction with Torsion Pendulum and Vibration Reed Methods

<div><p>In the traditional standard of internal friction measurement the torsion pendulum and vibration reed were preferentially recommended where the issue of strain amplitude dependence of internal friction was not concerned. To more precisely measure the internal friction and modulus at various strain amplitude, in this paper the strain amplitude dependence of internal friction and modulus is considered by analyzing the stress distribution in the sample in different internal friction measurement methods. The formulas for the measurement of internal friction and modulus versus strain-amplitude are obtained by re-deriving the principal equations for internal friction and modulus measurements by torsion pendulum and vibration reed methods from the basic definition of internal friction. This provides a new standard for precise measurement of internal friction at different strain-amplitude in the cases of high strain-amplitude excitation or high damping materials where amplitude dependent effects always appear.</p></div

Properties of the primary structure of the HMW-GS from <i>Ag. intermedium</i> in comparison with those of the representatives of wheat HMW-GS.

a<p>The nucleotide number of Open Reading Frame;</p>b<p>The number of Cys.</p

MALDI-TOF-MS analysis of peptide mass fingerprint of native 1Aiy1 subunit.

<p>Peptide mass is available at <a href="http://www.expasy.org/tools/peptide-mass.html" target="_blank">http://www.expasy.org/tools/peptide-mass.html</a>.</p

SDS-PAGE (A) and Western blotting (B) analysis of HMW-GSs of <i>Ag. intermedium</i>.

<p>Lane 1 shows the named HMW-GSs from common wheat variety Chinese Spring as a control. Lanes 2∼7 show the HMW-GSs from six representative seeds of the <i>Ag. intermedium</i> line used in this study. The seven expressed HMW-GSs with distinct electrophoretic mobility comparing with Chinese Spring were detected by SDS-PAGE (A) and were confirmed using Western blotting experiment with polyclonal antibody specific for HMW-GSs (B). Among the seven HMW-GSs from <i>Ag. intermedium</i>, three subunits (marked with solid triangles in lane 2 of B) share comparable electrophoretic mobility with Chinese Spring, the other four subunits (marked with hollow triangles in lane 2 of B) moved faster than those HMW-GSs from Chinese Spring.</p

SDS-PAGE (A) and Western blotting (B) analysis of HMW-GSs from <i>Ag. intermedium</i> and bacterial expression products.

<p>Lane 1 is HMW-GSs from common wheat variety Chinese Spring, the four expressed HMW-GSs are noted on left; Lane 2 is native HMW-GS from the seed of <i>Ag. intermedium</i> same as the lane 2 in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0087477#pone-0087477-g001" target="_blank">Figure 1</a>, the seven expressed HMW-GSs are marked with triangles; Lane 3, 5, 7, 9, 11, 13 and 15 are total cell proteins from IPTG induced <i>E. coli</i> containing pET-<i>Glu-1Ai1</i>, pET-<i>Glu-1Ai2</i>, pET-<i>Glu-1Ai3</i>, pET-<i>Glu-1Ai4</i>, pET-<i>Glu-1Ai5</i> pET-<i>Glu-1Ai6</i> and pET-<i>Glu-1Ai7</i>, respectively, whereas the dextral lanes for each of them shows the total cell proteins from their bacterial cells without induction of IPTG. The seven expressed target proteins in <i>E. coli</i>, which were detected by SDS-PAGE (marked with arrows in A) and were confirmed by Western blotting (lanes 3, 5, 7, 9, 11, 13 and 15 in B), share comparable electrophoretic mobility with those native HMW-GSs from <i>Ag. intermedium</i> (lane 2).</p

Illustration for the developmental mechanism of two hybrid HMW-GSs based on unequal double crossover hypothesis.

<p>The broken line box indicates the double crossover region. The xy and yx represent the hybrid subunit with 5′region of x-type and 3′region of y-type and the hybrid subunit with 5′region of y-type and 3′region of x-type, respectively.</p

Phylogenetic tree of <i>Thinopyrum intermedium</i> ( = <i>Ag. intermedium</i>) and some representative HMW-GSs from <i>Triticeae</i>.

<p>This phylogenetic tree was constructed with Maximum Likelihood Estimation method based on the nucleotide sequences encoding signal peptide and N-terminal conserved region of HMW-GSs plus the next three repeat units, one dodecapeptide, one undecapeptide and one hexapeptide repeat. D-hordein from barley was used as outgroup. The species names of HMW-GS genes in this figure are consistent with their accession names in GenBank, so here we replaced <i>Agropyron intermedium</i> with <i>Thinopyrum intermedium</i>.</p

Alignments and clustering analyses based on N-terminal (A), C-terminal (B) and the last 93 residues in the repetitive region (C) of the HMW-GSs from <i>Ag. intermedium</i> and several representative HMW-GSs from <i>Triticum</i> genus.

<p>Noticeably, the subunit 1Aix1 possesses a N-terminal clustered to x-type subunits (A) and a C-terminal and last part of repetitive region clustered to y-type subunits (B and C). Conversely, the subunit 1Aiy1 possesses a N-terminal more similar to y-type subunits (A) and a C-terminal and last part of repetitive region more similar to x-type subunits (B and C). The default parameters were used for full alignment and clustering analysis of sequences by aid of DNAMAN version 5. 2. 2.</p

Insight into the Near-Conduction Band States at the Crystallized Interface between GaN and SiN_<i>x</i> Grown by Low-Pressure Chemical Vapor Deposition

Constant-capacitance deep-level transient Fourier spectroscopy is utilized to characterize the interface between a GaN epitaxial layer and a SiN_<i>x</i> passivation layer grown by low-pressure chemical vapor deposition (LPCVD). A near-conduction band (NCB) state <i>E</i>_LP (<i>E</i>_C – <i>E</i>_T = 60 meV) featuring a very small capture cross section of 1.5 × 10^–20 cm^–2 was detected at 70 K at the LPCVD-SiN_<i>x</i>/GaN interface. A partially crystallized Si₂N₂O thin layer was detected at the interface by high-resolution transmission electron microscopy. Based on first-principles calculations of crystallized Si₂N₂O/GaN slabs, it was confirmed that the NCB state <i>E</i>_LP mainly originates from the strong interactions between the dangling bonds of gallium and its vicinal atoms near the interface. The partially crystallized Si₂N₂O interfacial layer might also give rise to the very small capture cross section of the <i>E</i>_LP owing to the smaller lattice mismatch between the Si₂N₂O and GaN epitaxial layer and a larger mean free path of the electron in the crystallized portion compared with an amorphous interfacial layer