62 research outputs found

    Oersted Field and Spin Current Effects on Magnetic Domains in [Co/Pd]

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    An out-of-plane Oersted field produced from a current-carrying Au wire is used to induce local domain formation in wires made from [Co/Pd][subscript 15] multilayers with perpendicular anisotropy. A 100 ns pulsed current of 56-110 mA injected into the Au wire created a reverse domain size of 120-290 nm in a Co/Pd nanowire on one side of the Au wire. A Biot-Savart model was used to estimate the position dependence of the Oersted field around the Au wire. The shape, size, and location of the reversed region of Co/Pd were consistent with the magnitude of the Oersted field and the switching field distribution of the unpatterned film. A current density of 6.2 × 10[superscript 11] Am[superscript -2] in the Co/Pd nanowire did not translate the domain walls due to low spin transfer efficiency, but the Joule heating promoted domain growth in a field below the coercive field.National Science Foundation (U.S.). Materials Research Science and Engineering Centers (Program) (Award DMR1419807

    Present-day kinematics and seismic potential of the Ganzi-Yushu fault, eastern Tibetan plateau, constrained from InSAR

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    In recent years, earthquakes have occurred frequently on the southeastern edge of the Tibetan Plateau, and the seismic hazard is high. However, because of the remote location of the Ganzi-Yushu fault zone, no high-resolution geodetic measurements of this region have been made. The radar line-of-sight deformation field of the Ganzi-Yushu fault was obtained using seven-track ascending and descending Sentinel-A/B interferometric synthetic aperture radar (InSAR) data from 2014 to 2020. Using the InSAR and published Global Navigation Satellite System (GNSS) data, we calculated the 3D deformation field in the study area, investigated the segment-specific fault slip rate, and inverted the fault slip distribution pattern using the steepest descent method. We then evaluated the seismic hazard using the strain rate field and slip deficit rate. The main findings of this study include the following. 1) The slip rate of the Ganzi-Yushu fault gradually increases from 2.5 to 6.8 mm/yr from northwest to southeast. 2) A high-resolution strain rate map shows high-value anomalies in the Yushu and Dangjiang areas. 3) Our comprehensive analysis suggests that the seismic hazard of the Dangjiang and Dengke segments with high slip deficits cannot be ignored

    Domain configurations in Co/Pd and L10-FePt nanowire arrays with perpendicular magnetic anisotropy

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    Perpendicular magnetic anisotropy [Co/Pd]15 and L10-FePt nanowire arrays of period 63 nm with linewidths 38 nm and 27 nm and film thickness 27 nm and 20 nm respectively were fabricated using a self-assembled PS-b-PDMS diblock copolymer film as a lithographic mask. The wires are predicted to support Neel walls in the Co/Pd and Bloch walls in the FePt. Magnetostatic interactions from nearest neighbor nanowires promote a ground state configuration consisting of alternating up and down magnetization in adjacent wires. This was observed over ~75% of the Co/Pd wires after ac-demagnetization but was less prevalent in the FePt because the ratio of interaction field to switching field was much smaller. Interactions also led to correlations in the domain wall positions in adjacent Co/Pd nanowires. The reversal process was characterized by nucleation of reverse domains, followed at higher fields by propagation of the domains along the nanowires. These narrow wires provide model system for exploring domain wall structure and dynamics in perpendicular anisotropy systems

    Rhinolophidae Gray 1825

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    RHINOLOPHIDAE During our surveys, 12 species of horseshoe bats were captured (for capture sites, measurements and status, see Table 1; for representative echolocation calls, see Fig. 2; see also Appendix), of which two represent new records for China: R. marshalli and R. stheno. We also captured bats that fit descriptions of R. siamensis, recognised as a distinct species in Smith and Xie (2008). Among these 12 species, R. ferrumequinum and R. pusillus are common and widespread in China.Published as part of Zhang, Libiao, Jones, Gareth, Zhang, Jinshuo, Zhu, Guangjian & Parsons, Stuart, 2009, Recent surveys of bats (Mammalia: Chiroptera) from China. I. Rhinolophidae and Hipposideridae, pp. 71-88 in Acta Chiropterologica 11 (1) on page 73, DOI: 10.3161/150811009X465703, http://zenodo.org/record/394451

    Rhinolophus rex G. M. Allen 1923

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    <p> <i>Rhinolophus rex</i> G. M. Allen, 1923</p> <p>King horseshoe bat</p> <p> <i>Rhinolophus paradoxolophus</i> (Bourret, 1951)</p> <p>Bourret’s horseshoe bat</p> <p> These taxa appear to be very closely related and there has been some disagreement in the literature regarding whether or not they represent discrete species. For these reasons they are considered together here. <i>Rhinolophus rex</i> has previously been separated from <i>R. paradoxolophus</i> on the basis of small differences in external, cranial and dental measurements with the former considered to be the fractionally larger species. For example, <i>R. paradoxolophus</i> has a forearm length of 50.5–57 mm, <i>R. rex</i> 56.5–63 mm (Csorba <i>et al.</i>, 2003). In our surveys, several bats captured in Guangxi had forearm lengths that would classify them as <i>R. paradoxolophus</i>, while our Yunnan bat had a forearm length that fits the measurements for <i>R. rex</i>. Despite these size differences, these bats called at similar call frequencies. Francis (in Eger and Fenton 2003) record- ed <i>R. paradoxolophus</i> at 22–25 kHz in Lao PDR, and hence it appears that the call frequencies used by <i>R. paradoxolophus</i> and <i>R. rex</i> are identical. Eger and Fenton (2003) recorded <i>R. paradoxolophus</i> at 43 kHz in China, but presumably measured the third harmonic of a signal with a fundamental at about 14 kHz. We consider that the small differences in body size are inadequate descriptors of taxonomic distinctiveness between <i>R. paradoxolophus</i> and <i>R. rex</i>, and given that their echolocation calls are very similar we suggest they are probably the same taxon. <i>Rhinolophus paradoxolophus</i> occurs at more southerly locations than <i>R. rex</i>, and the forms are probably best recognized as geographical races (subspecies). Because <i>R. rex</i> (1923) was named before <i>R. paradoxolophus</i> (1951) we suggest that the taxa are synonymised under the name <i>R. rex</i> and considered as one species. An account of the biology of <i>R. paradoxolophus</i> is given by Eger and Fenton (2003).</p> <p> <i>Rhinolophus rex</i></p> <p> FA — 51.6–57.3 mm, mass — 10.8–14 g. Four males and 10 females were captured in Guangxi, Guizhou and Yunnan. <i>Rhinolophus rex</i> calls at a very low frequency, FMAXE 23.7–26.4 kHz, with calls dominated by the second harmonic.</p> <p> Previous records from China (for <i>R. rex</i>): Chongqing, Guangdong, Guangxi, Guizhou, Sichuan and Yunnan (Zhang, 1997; Wang, 2003).</p> <p> <i>Ecological Notes</i></p> <p>This species is restricted to southern provinces where it is only encountered in small numbers in caves. Echolocation calls are audible at close range to the unaided ear.</p>Published as part of <i>Zhang, Libiao, Jones, Gareth, Zhang, Jinshuo, Zhu, Guangjian & Parsons, Stuart, 2009, Recent surveys of bats (Mammalia: Chiroptera) from China. I. Rhinolophidae and Hipposideridae, pp. 71-88 in Acta Chiropterologica 11 (1)</i> on pages 78-79, DOI: 10.3161/150811009X465703, <a href="http://zenodo.org/record/3944511">http://zenodo.org/record/3944511</a&gt

    Rhinolophus marshalli Thonglongya 1973

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    Rhinolophus marshalli Thonglongya, 1973 Marshall’s horseshoe bat FA — 38.9–47.1 mm, mass — 5.8–7.0 g. Three males and four females were netted in Yunnan Province on 8 September 2003, representing a new species record for China. Morphological and cranial measurements were described by Zhang L. B. et al. (2005). These bats called at 39.2–41.6 kHz (FA 43.8–47.1 mm). On 13 October 2007, three males (FA 44.0– 46.4 mm, mass 5.8–7.0 g, FMAXE 41.8–42.3 kHz) were also netted in Yunnan Province and on 21 June 2007, we netted 6 males and 5 females (FA — 38.9–44.1 mm, FMAX — 43.0–44.5 kHz) in Guangxi. Ecological Notes Our data represent new records for China in subtropical areas, always involving small numbers of individuals. The species is found in neighboring Vietnam (Hendichsen et al., 2001).Published as part of Zhang, Libiao, Jones, Gareth, Zhang, Jinshuo, Zhu, Guangjian & Parsons, Stuart, 2009, Recent surveys of bats (Mammalia: Chiroptera) from China. I. Rhinolophidae and Hipposideridae, pp. 71-88 in Acta Chiropterologica 11 (1) on page 78, DOI: 10.3161/150811009X465703, http://zenodo.org/record/394451

    Rhinolophus ferrumequinum

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    Rhinolophus ferrumequinum (Schreber, 1774) Greater horseshoe bat FA — 56.5–62.0 mm, mass — 16.5–32.6 g. A widespread bat in China: we captured bats in Beijing, Guangxi, Henan, Hubei, Jiangxi, Jilin, Shandong, Shanxi, Sichuan, Tianjin and Yunnan. Bats assigned to R. ferrumequinum in China have lower call frequencies and longer forearms (72.0–83.5 kHz, 56.5–62.0 mm, respectively) than those sampled in continental Europe and the UK (81–84 kHz, 50.6–59.0 mm FA in UK — Heller and Helversen, 1989; Jones and Rayner, 1990; Park et al., 2000; Andrews and Andrews, 2003; Ransome 2008). Genetic analyses of microsatellite loci and mitochondrial DNA reveal deep divisions among populations within China, and also between the Chinese populations and those from the Middle East and Europe (Rossiter et al., 2007; Flanders et al. 2009). Bats from southwest China typically emitted echolocation calls with FMAXE at 72.0 kHz to 73.9 kHz (Yunnan and Sichuan, respectively), while those from east China are higher again (♂♂ 74.8–76.8 kHz; ♀♀ 76.4–77.1 kHz). Moreover, bats from Japan that are usually considered a discrete subspecies (R. f. nippon) show a further decrease in call frequency (ca. 65 kHz — Taniguchi, 1985; Fukui et al., 2004) and are typically larger than most bats on the Chinese mainland. In conflict with this general trend was one bat from Jilin that emitted echolocation calls at 65 kHz and also appeared to show greater mtDNA sequence affiliation to the bats from Japan. Hence it is likely that the nippon lineage has recolonised China from Japan (Flanders et al., 2009). Such large differences in call frequency and corresponding genetic distinctiveness suggest that populations of this species in China might warrant taxonomic revision. Previous records from China: Anhui, Beijing, Fujian, Gansu, Guangxi, Guizhou, Hebei, Henan, Hunan, Hubei, Jiangsu, Jiangxi, Jilin, Liaoning, Ningxia, Shaanxi, Shanxi, Shandong, Shanghai, Sichuan, Yunnan and Zhejiang (Zhang, 1997; Wang, 2003). Ecological Notes Although widespread, the species was rarely encountered in large numbers. It was always found in caves. Breeding was confirmed in Du Cave, Tianjin where young were noted during late June. The species appears to eat mainly moths and beetles, as in Britain (Jones, 1990). Analysis of 60 droppings from Beijing collected in August 2003 revealed average percentage volumes of 96.9% moths, 2.7% beetles, 0.4% dipterans.Published as part of Zhang, Libiao, Jones, Gareth, Zhang, Jinshuo, Zhu, Guangjian & Parsons, Stuart, 2009, Recent surveys of bats (Mammalia: Chiroptera) from China. I. Rhinolophidae and Hipposideridae, pp. 71-88 in Acta Chiropterologica 11 (1) on pages 75-76, DOI: 10.3161/150811009X465703, http://zenodo.org/record/394451

    Rhinolophus pearsonii Horsfield 1851

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    <i>Rhinolophus pearsonii</i> Horsfield, 1851 <p>Pearson’s horseshoe bat</p> <p> <i>Rhinolophus yunanensis</i> Dobson, 1872</p> <p>Dobson’s horseshoe bat</p> <p> <i>Rhinolophus yunanensis</i> (found in NE India, north Myanmar, SE China and Thailand) is normally recognised as a species distinct from <i>R. pearsoni</i> (see Csorba <i>et al.</i>, 2003). The main reason for this distinction appears to be that <i>R. yunanensis</i> is slightly larger (e.g., forearm lengths 51.5–64.0 mm versus 47.0–56.0 mm in <i>R</i>. <i>pearsoni</i> — Csorba <i>et al.</i>, 2003). However, the overlap in forearm lengths between the two species is substantial; we have found consistency in echolocation call frequencies (suggesting all bats belong to one species) of bats that would be described as <i>R. pearsoni</i> and <i>R. yunanensis</i> on the basis of forearm lengths (i.e., bats with forearm length <51.5 mm can have a similar call frequency to bats with forearm length> 56 mm). Forearm length is therefore a weak indicator of species distinctiveness, and better diagnostic features are need- ed to adequately separate these taxa. Echolocation call frequency may prove useful in this respect. <i>R. pearsonii</i> from Anhui, Jiangxi, and Fujian call at 64.2–70 kHz, while those from Guangxi call at 57.6–61.6 kHz. Females call at higher frequencies than males, by about 2 kHz. Robinson (1996) reported that <i>R. pearsonii</i> in Malaysia emits echolocation calls with FMAXE at 65.0 kHz. <i>Rhinolophus yunanensis</i> in Thailand calls at considerably lower frequencies, typically around 51–52 kHz (P. Soisook, personal communication). One bat captured in Sichuan emitted calls that were considerably lower in FMAXE (48 kHz), and was probably therefore <i>R. yunanensis</i>. Otherwise, on the basis of echolocation call frequencies, most of the records below probably refer to <i>R. pearsonii</i>. In other parts of S Asia, differences between <i>R. yunanensis</i> and <i>R. pearsoni</i> may be more apparent. Moreover, an intermediate species — <i>R. chiewkweeae</i> — has recently been described from peninsular Malaysia (Yoshiyuki and Lim, 2005).</p> <p> <i>Rhinolophus pearsonii</i></p> <p>FA — 51–56 mm, mass — 11.0– 17.1 g. Fifty males and 39 females were captured from Anhui, Fujian, Guangdong, Guangxi, Guizhou, Hunan, Jiangxi, Sichuan and Yunnan.</p> <p> Previous records from China (<i>R. pearsonii</i>): Anhui, Fujian, Guangdong, Guangxi, Guizhou, Hunan, Hubei, Jiangxi, Tibet, Shaanxi, Sichuan, Yunnan and Zhejiang (Zhang, 1997; Wang, 2003). <i>Rhinolophus yunanensis</i> previously reported from Yunnan (Wang, 2003).</p> <p> <i>Ecological Notes</i></p> <p> <i>Rhinolophus pearsonii</i> was often found in quite cool conditions in montane areas of high elevation, as was our likely record of <i>R. yunanensis</i>. All records were of small numbers of bats in caves.</p>Published as part of <i>Zhang, Libiao, Jones, Gareth, Zhang, Jinshuo, Zhu, Guangjian & Parsons, Stuart, 2009, Recent surveys of bats (Mammalia: Chiroptera) from China. I. Rhinolophidae and Hipposideridae, pp. 71-88 in Acta Chiropterologica 11 (1)</i> on page 79, DOI: 10.3161/150811009X465703, <a href="http://zenodo.org/record/3944511">http://zenodo.org/record/3944511</a&gt
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