Structural synthesis for broken strands repair operation metamorphic mechanism of EHV transmission lines

Special operation requirements are needed for repositing broken strands of extra-high-voltage (EHV) power transmission lines before repairing. Metamorphic mechanism is applied to satisfy the requirements and a novel structural synthesis method is proposed, considering the forms and structures of constrained metamorphic joints. Metamorphic cyclogram and equivalent resistance gradient matrix of metamorphic joints are obtained by analyzing the repairing operation. Meanwhile, the source metamorphic mechanism with structure of non-constrained metamorphic joints is selected. Constrained form/structure matrix of metamorphic joints is built according to metamorphic cyclogram and equivalent resistance gradient matrix. The relation between constraint force changes of joints and form/structure of metamorphic joints is then obtained; and all the eight corresponding structures of constrained metamorphic mechanism are synthesized. One of the eight mechanisms is chosen as the broken strands reposition metamorphic mechanism, and its topological transformations of working configuration are analyzed to verify the feasibility and practicality of structural synthesis method proposed in this paper

Structural Synthesis and Configuration Analysis of Broken Strands Repair Operation Metamorphic Mechanism

Appling metamorphic mechanism to satisfy the special operation requirements of the reposition before repairing operation for broken strands of extra-high-voltage (EHV) power transmission lines, a novel structural synthesis method of metamorphic mechanism is proposed considering the forms and structures of constrained metamorphic joints. According to the metamorphic cyclogram and the equivalent resistance gradient matrix, constrained form/structure matrix of metamorphic joints is built, the relation with constraint force changes of joints and form/structure of metamorphic joints is obtained; and further all the eight corresponding structures of constrained metamorphic mechanism are synthesized by the method. One of the eight mechanisms is chosen as the broken strands reposition metamorphic mechanism, and its topological transformations of working configuration are analyzed to verify the feasibility and practicality of structural synthesis method proposed in this paper

Long term monitoring of mode switching for PSR B0329+54

The mode switching phenomenon of PSR B0329+54 is investigated based on the long-term monitoring from September 2003 to April 2009 made with the Urumqi 25m radio telescope at 1540 MHz. At that frequency, the change of relative intensity between the leading and trailing components is the predominant feature of mode switching. The intensity ratios between the leading and trailing components are measured for the individual profiles averaged over a few minutes. It is found that the ratios follow normal distributions, where the abnormal mode has a wider typical width than the normal mode, indicating that the abnormal mode is less stable than the normal mode. Our data show that 84.9% of the time for PSR B0329+54 was in the normal mode and 15.1% was in the abnormal mode. From the two passages of eight-day quasi-continuous observations in 2004, and supplemented by the daily data observed with 15 m telescope at 610 MHz at Jodrell Bank Observatory, the intrinsic distributions of mode timescales are constrained with the Bayesian inference method. It is found that the gamma distribution with the shape parameter slightly smaller than 1 is favored over the normal, lognormal and Pareto distributions. The optimal scale parameters of the gamma distribution is 31.5 minutes for the abnormal mode and 154 minutes for the normal mode. The shape parameters have very similar values, i.e. 0.75^{+0.22}_{-0.17} for the normal mode and 0.84^{+0.28}_{-0.22} for the abnormal mode, indicating the physical mechanisms in both modes may be the same. No long-term modulation of the relative intensity ratios was found for both the modes, suggesting that the mode switching was stable. The intrinsic timescale distributions, for the first time constrained for this pulsar, provide valuable information to understand the physics of mode switching.Comment: 31 pages,12 figures, Accepted by the Ap

Possible evidence that pulsars are quark stars

It is a pity that the real state of matter in pulsar-like stars is still not determined confidently because of the uncertainty about cold matter at supranuclear density, even 40 years after the discovery of pulsar. Nuclear matter (related to neutron stars) is one of the speculations for the inner constitution of pulsars even from the Landau's time more than 70 years ago, but quark matter (related to quark stars) is an alternative due to the fact of asymptotic freedom of interaction between quarks as the standard model of particle physics develops since 1960s. Therefore, one has to focus on astrophysical observations in order to answer what the nature of pulsars is. In this presentation, I would like to summarize possible observational evidence/hints that pulsar-like stars could be quark stars, and to address achievable clear evidence for quark stars in the future experiments.Comment: 6 pages, 2 figures; a talk at the international conference "Astrophysics of Compact Objects" (July 1-7, 2007; Huangshan, China); http://vega.bac.pku.edu.cn/rxxu/publications/index_C.htm. A mistake in Fig.1 is corrected; Correction of typo

Small molecule and peptide inhibitors of the pro-survival protein Mcl-1

The ability of protein–protein interactions to regulate cellular processes in both beneficial and detrimental ways has made them obvious drug targets. The Bcl-2 family of proteins undergo a series of protein–protein interactions which regulate the intrinsic cell-death pathway. The pro-survival members of the Bcl-2 family, including Bcl-2, Bcl-xL, and Mcl-1, are commonly overexpressed in a number of human cancers. Effective modulators of members of the Bcl-2 family have been developed and are undergoing clinical trials, but the efficient modulation of Mcl-1 is still not represented in the clinic. In addition, Mcl-1 is a major cause of resistance to radio- and chemotherapies, including inhibitors that target other Bcl-2 family members. Subsequently, the inhibition of Mcl-1 has become of significant interest to the scientific community. This review covers the progress made to date in modulating the activity of Mcl-1, by both stapled peptides and small molecules. The development of peptides as drug candidates, and the advancement of experimental and computational techniques used to discover small molecules are also highlighted

Astro-quark matter: a challenge facing astroparticle physics

Quark matter both in terrestrial experiment and in astrophysics is briefly reviewed. Astrophysical quark matter could appear in the early Universe, in compact stars, and as cosmic rays. Emphasis is put on quark star as the nature of pulsars. Possible astrophysical implications of experiment-discovered sQGP are also concisely discussed.Comment: 14 pages, 4 figures and 1 table; talk presented at CosPA2007 (International Symposium on Cosmology and Particle Astrophysics, Taipei, Nov. 13-15, 2007