Various solution-treatments were applied on a rapidly solidified and subsequently rolled Mg-7.50Al-1.07Ca-0.17Mn (mass%) alloy sheet, and a room-temperature stretch formability, tensile properties, ...microstructures, and textures of the solution-treated sheets have been investigated. Although the solution-treatment at 400 °C gives high strengths, the sheet shows poor room-temperature stretch formability with the Index Erichsen value of 4.8 mm due to densely dispersed second phase particles. Also, the particles tend to distribute to the rolling direction, leading to limited elongation to failure of 11.0% along the transverse direction. The solution-treatment at higher temperature leads to the sparse and relatively uniform dispersion of the particles. This results in the significant improvement in the room-temperature stretch formability and ductility. The Index Erichsen increases to 6.8 mm by the solution-treatment at 450 °C for 4 h, and the sheet shows large elongation to failure of 19.1% and 17.1% along the rolling and transverse directions, respectively. The sheet also exhibits high strengths and in-plane isotropic properties, tensile strength over 320 MPa and 0.2% proof stress of ~180 MPa could be obtained due to fine grain structure with the average grain size of 9.5 μm.
Transporter‐mediated drug–drug interactions (DDIs) are among the most important of the clinically relevant pharmacokinetic DDIs. We investigated the validity of a static prediction of area under the ...plasma concentration–time curve (AUC) ratios (AUCRs; AUCwith inhibitor/AUCcontrol) using in vitro inhibition profiles, and selected the types of assumptions that improved the prediction accuracy with minimizing false‐negative predictions. We used data from 58 DDI studies involving 12 substrates of hepatic organic anion–transporting polypeptides (OATPs). With original assumptions regarding the maximal increase in intestinal availability, maximum unbound concentration at the inlet to the liver, and inhibition of only the hepatic uptake process, the predicted AUCRs were comparable to those reported within a two/threefold error margin in 44/52 studies, whereas in 16 studies, the predictions were judged to be false‐negatives. When the inhibitory effects on both hepatic uptake and efflux/metabolisms were considered, the overall prediction accuracy became worse, although the false‐negative prediction decreased to 11 studies. This illustrates that if appropriate assumptions are selected, unnecessary clinical DDI studies can be reasonably avoided.
Clinical Pharmacology & Therapeutics (2012); 91 6, 1053–1064. doi:10.1038/clpt.2011.351
An anomalous in-plane anisotropy was found in a basal-textured Mg–Al–Zn alloy sheet due to a minor fraction of transverse direction (TD)-orient (0001) poles induced high activation of tensile ...twinning. This led to deteriorated tensile properties along the TD, emphasizing an importance of microtexture designing for wrought magnesium with high-performance.
•A basal-textured AZ31 alloy contains a minor fraction of TD-orient (0001) poles.•TD-orient grains favor the activation of tensile twinning during the TD-tension.•High fraction of tensile twinning leads to deteriorated strength and ductility.
A search for the heaviest isotopes of fluorine, neon, and sodium was conducted by fragmentation of an intense ^{48}Ca beam at 345 MeV/nucleon with a 20-mm-thick beryllium target and identification ...of isotopes in the large-acceptance separator BigRIPS at the RIKEN Radioactive Isotope Beam Factory. No events were observed for ^{32,33}F, ^{35,36}Ne, and ^{38}Na and only one event for ^{39}Na after extensive running. Comparison with predicted yields excludes the existence of bound states of these unobserved isotopes with high confidence levels. The present work indicates that ^{31}F and ^{34}Ne are the heaviest bound isotopes of fluorine and neon, respectively. The neutron dripline has thus been experimentally confirmed up to neon for the first time since ^{24}O was confirmed to be the dripline nucleus nearly 20 years ago. These data provide new keys to understanding the nuclear stability at extremely neutron-rich conditions.
Achievements in space robotics Yoshida, K.
IEEE robotics & automation magazine,
12/2009, Letnik:
16, Številka:
4
Journal Article
Recenzirano
Outer space is an ultimate field for the application of robotics technology. As outer space is a harsh environment with extreme temperatures, vacuum, radiation, gravity, and great distances, human ...access is very difficult and hazardous and is therefore limited. To assist human activities in space for constructing and maintaining space modules and structures, robotic manipulators have been playing essential roles in orbital operations. Moreover, expanding the horizons of exploration beyond the areas of human access, robots that land and travel on planetary surfaces have been greatly contributing to our knowledge of the solar system. New challenges are expected in the future. This article consists of three parts. In the first part, the achievements of orbital robotics technology in the last decade are reviewed, highlighting the Engineering Test Satellite (ETS-VII) and Orbital Express flight demonstrations. In the second part, some of the selected topics of planetary robotics from the field robotics research point of view are described. Recent achievements in the author's laboratory are added as an illustrative example. Finally, technological challenges to asteroid robotics are discussed. When designing a robot to explore the surface of an asteroid, microgravity raises an interesting problem of how to stick and move on the surface. Some ideas to address these questions are introduced.
Spermatozoa generated in the testis are immature and incompetent for fertilization. During their journey toward the egg, the sperm acquire fertility and achieving fertilization. These sperm ...modifications to ensure fertilization are induced by many female or male extra-sperm factors: for example, sperm motility-activating factors from the egg jelly, sperm attractants from the eggs, and decapacitation factors from the seminal plasma. The factors controlling sperm fertility are myriad and species specific; they may be peptides, sugar chains, or small organic compounds. Nevertheless, the fundamental mechanisms underlying fertilization must be common among all animals; increase in Ca²⁺i triggers all the steps in the process of fertilization, and cAMP plays important roles in many steps. Elucidating the dynamic functional and morphological changes in sperm cells is important for understanding the regulation of fertilization. Here, we introduce the diversity and generality of the control of sperm fertility.
A strong and ductile Mg-8Al-1Zn-1Ca-0.3Mn (wt%) alloy sheet has been successfully developed via commercial rolling process. The ultimate tensile strength, 0.2% proof stress, and elongation to failure ...along the rolling direction of the sheet are 371 MPa, 275 MPa, and 17.1%, respectively. The high strength and ductility are attributed to the fine recrystallized grains and densely dispersed fine Mg17Al12 precipitates. Further, due to its isotropic basal texture, the Mg-8Al-1Zn-1Ca-0.3Mn alloy sheet shows little in-plane anisotropy. The ultimate tensile strength, 0.2% proof stress, and elongation to failure along the 45° and transverse direction of the sheet are almost the same as those in the rolling direction. The good tensile properties can be realized by using only inexpensive ingredients and commercial rolling process; therefore, the Mg-8Al-1Zn-1Ca-0.3Mn alloy sheet will be a candidate as structural materials for transportation vehicles.
Quasi‐biennial oscillations (QBOs) in thirteen atmospheric general circulation models forced with both observed and annually repeating sea surface temperatures (SSTs) are evaluated. In most models ...the QBO period is close to, but shorter than, the observed period of 28 months. Amplitudes are within ±20% of the observed QBO amplitude at 10 hPa, but typically about half of that observed at lower altitudes (50 and 70 hPa). For almost all models, the oscillation's amplitude profile shows an overall upward shift compared to reanalysis and its meridional extent is too narrow. Asymmetry in the duration of eastward and westward phases is reasonably well captured, though not all models replicate the observed slowing of the descending westward shear. Westward phases are generally too weak, and most models have an eastward time mean wind bias throughout the depth of the QBO. The intercycle period variability is realistic and in some models is enhanced in the experiment with observed SSTs compared to the experiment with repeated annual cycle SSTs. Mean periods are also sensitive to this difference between SSTs, but only when parametrized non‐orographic gravity wave (NOGW) sources are coupled to tropospheric parameters and not prescribed with a fixed value. Overall, however, modelled QBOs are very similar whether or not the prescribed SSTs vary interannually. A portrait of the overall ensemble performance is provided by a normalized grading of QBO metrics. To simulate a QBO, all but one model used parametrized NOGWs, which provided the majority of the total wave forcing at altitudes above 70 hPa in most models. Hence the representation of NOGWs either explicitly or through parametrization is still a major uncertainty underlying QBO simulation in these present‐day experiments.
Quasi‐biennial oscillations (QBOs) in thirteen atmospheric general circulation models forced with both observed (orange) and annually repeating (grey) sea surface temperatures (SSTs) are evaluated over a range of metrics and compared against reanalysis (blue‐green). Mean periods are sensitive to this difference between SSTs, but only when parametrized non‐orographic gravity wave sources are coupled to tropospheric parameters (60LCAM5 and right there of) and not prescribed with fixed values. Overall, however, modelled QBOs are very similar whether or not the prescribed SSTs vary interannually.
Topological defects embedded in or combined with domain walls have been proposed in various systems, some of which are referred to as domain wall skyrmions or domain wall bimerons. However, the ...experimental observation of such topological defects remains an ongoing challenge. Here, using Lorentz transmission electron microscopy, we report the experimental discovery of domain wall bimerons in chiral magnet Co-Zn-Mn(110) thin films. By applying a magnetic field, multidomain structures develop, and simultaneously, chained or isolated bimerons arise as the localized state between the domains with the opposite in-plane components of net magnetization. The multidomain formation is attributed to magnetic anisotropy and dipolar interaction, and domain wall bimerons are stabilized by the Dzyaloshinskii-Moriya interaction. In addition, micromagnetic simulations show that domain wall bimerons appear for a wide range of conditions in chiral magnets with cubic magnetic anisotropy. Our results promote further study in various fields of physics.
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