4,173 research outputs found
A review of autonomous docking technologies for an unmanned aircraft carrier
No full textAerial carrier is becoming a hotspot in Remote Piloted Aircraft System (RPAS) research area recently. As a variant of the general RPAS swarm, this technology is believed to be promising in both military and civilian applications. For example, it could enhance the safety of a military surveillance mission, it could enlarge the surveillance region coverage and it could extend the communication range of any single RPAS. One essential problem for the realisation of the aerial carrier is the autonomous docking in the air. This paper presents a review of autonomous docking techniques ranging from active LED recognition to passive laser scanning and three-dimensional (3D) remodelling. It is aimed at providing a broad perspective on the statues of the recognition and position estimation problems
Development of an active gimbal system for a directional antenna on a small RPA
No full textRemotely piloted aircraft are still not yet a feature of everyday life, however the numbers in use is growing rapidly and the range of operations that they support increasing. This conference, organised by the Royal Aeronautical Society’s Unmanned Aircraft Systems Specialist Group, will provide delegates with essential information on the factors that are supporting the proliferation of civil use as well as providing clear insights into the regulatory and other constraints in place to ensure public safety and privacy. The capabilities, opportunities and technologies are developing at a rapid pace and will be outlined by various experts from UK, Europe and America. In addition speakers from UK Government organisations will present a vision of the support available, the requirements to be adhered to and the way in which regulations are developing. - See more at: http://aerosociety.com/Events/Event-List/1402/RPAS-Today-Opportunities-and-Challenges#sthash.CHtG2mPW.dpu
A copper chaperone for superoxide dismutase that confers three types of copper/zinc superoxide dismutase activity in Arabidopsis.
No full textPredicting risk for early infantile atopic dermatitis by hereditary and environmental factors.
No full textDevelopment of active directional antennae for use in small UAVs
No full textFive different light-weight, medium and high gain directional antennas have been developed, which can be operated together with a gimbals system on the UAV or an antenna tracker system on the ground or with both to extend the range of communication and improve the quality of video signals. The antennas are based on PCB to reduce the mass. There are two types of antennas developed for different transmission frequency: Patch Antenna and Yagi-Uda Antenna. The gimbals system are under developing, which will be based on Arduino Micro Development Board, also quite light, and the board will drive a pan and tilt structure constructed with two small but powerful servos to ensure the antenna to point at the ground station
Numerical investigation of a jet from a blunt body opposing a supersonic flow
No full textNumerical investigation of a sonic jet from a blunt body opposing a supersonic flow with a free stream Mach number M1 D 2:5 was carried out using large-eddy simulation for two total pressure ratios of the jet to the free stream, i.e. P D 0:816 and 1.633. Results have been validated carefully against experimental data. Various fundamental mechanisms dictating the flow phenomena, including shock/jet interaction, shock/shear-layer interaction, turbulent shear-layer evolution and coherent structures, have been studied systematically. Based on the analysis of the flow structures and features, two typical flow states, i.e. unstable and stable states corresponding to the two values of P, are identified and the behaviours relevant to the flow states are discussed. Small-scale vortical structures mainly occur in the jet column, and largescale vortices develop gradually in a recirculation region when the jet terminates through a Mach disk and reverses its orientation as a conical free shear layer. The turbulent fluctuations are enhanced by the rapid deviation of the shear layer and the interaction with shock waves. Moreover, the coherent structures of the flow motion are analysed using the proper orthogonal decomposition technique. It is found that the dominant mode in the cross-section plane exhibits an antisymmetric character for the unstable state and an axisymmetric one for the stable state, while statistical analysis of unsteady loads indicates that the side loads can be seen as a rotating vector uniformly distributed in the azimuthal direction. Further, we clarify a feedback mechanism whereby the unsteady motion is sustained by the upstream-propagating disturbance to the Mach disk through the recirculation subsonic region and downstream propagation in the conical shear layer. Feedback models are then proposed which can reasonably well predict the dominant frequencies of the two flow states. The results obtained in this study provide physical insight into the understanding of the mechanisms relevant to the opposing jet/supersonic flow interaction
Tangle-bearing neurons survive despite disruption of membrane integrity in a mouse model of tauopathy
No full textNeurofibrillary tangles (NFTs) are associated with neuronal loss and correlate with cognitive impairment in Alzheimer disease, but how NFTs relate to neuronal death is not clear. We studied cell death in Tg4510 mice that reversibly express P301L mutant human tau and accumulate NFTs using in vivo multiphoton imaging of neurofibrillary pathology, propidium iodide (PI) incorporation into cells, caspase activation, and DNA labeling. We first observed that in live mice, a minority of neurons were labeled with the caspase probe or with PI fluorescence. These markers of cell stress were localized in the same cells and appeared specifically within NFT-bearing neurons. Contrary to expectations, the PI-stained neurons did not die during a day of observation; the presence of Hoechst-positive nuclei in them on the subsequent day indicated that the NFT-associated membrane disruption, as suggested by PI staining, and caspase activation do not lead to immediate death of neurons in this tauopathy model. This unique combination of in vivo multiphoton imaging with markers of cell death and pathological alteration is a powerful tool for investigating neuronal damage associated with neurofibrillary pathology
Sulcolotis ovalis Liu & Wang & Guo & Chen & Wang 2022, sp. nov.
No full textSulcolotis ovalis Liu & Wang sp. nov. (Figs 3a–g) Diagnosis. This species is most similar to S. threadis sp. nov. in external appearance but can be distinguished from the latter by the penis guide shorter than parameres. In S. threadis sp. nov., the penis guide is nearly as long as parameres in lateral view. Description. TL: 2.63–2.86mm, TW: 2.26–2.37mm, TH: 1.37–1.59mm, TL/TW: 1.16–1.21, PL/PW: 0.28– 0.30, EL/EW: 0.94–0.99, HW/PW: 0.56–0.58, PW/TW: 0.63–0.64, HW/TW: 0.35–0.37, Eye W/HW: 0.43–0.46. Head reddish brown. Elytra reddish brown with a long ovate black spot situated at 1/3 elytral length to base. Underside yellowish brown, except metaventrite and the middle part of the first abdominal ventrite reddish brown. Body rounded, weakly convex, shiny and glabrous. Eyes finely faceted, interocular distance 0.45 times width of head. Frons broad with irregular transparent spots, punctures uniform and dense (Fig. 3c). Pronotum 0.64 times of elytral width (PW/TW=1:1.6), moderately transverse, punctures uniform and dense (Fig. 3c). Elytra with uniform and dense punctures (Figs 3a–c). Ventrite 6 subhemisphenical and ventrite 7 nearly straight (Fig. 3g). Male genitalia: penis relatively short and slender, apex pointed, penis capsule with nearly same length of inner arm and outer arm. Tegmen with penis guide in lateral view slender, widest at base, narrowing to apex, distinctly shorter than parameres. Type material. Holotype: ♂, Philippines, Butuan Mindanao, Baker (USNM). Paratypes: 2 ♀♀, same data as holotype (USNM). Distribution. Philippines (Mindanao). Etymology. The specific epithet is formed from the Latin noun ovalis, referring to elytra with a long ovate black spot.Published as part of Liu, Liyuan, Wang, Yan, Guo, Qiuhong, Chen, Xiaosheng & Wang, Xingmin, 2022, Three new species of the genus Sulcolotis Miyatake (Coleoptera, Coccinellidae Sticholotidini) from the Philippines, pp. 75-82 in Zootaxa 5168 (1) on pages 78-79, DOI: 10.11646/zootaxa.5168.1.6, http://zenodo.org/record/687646
Sinovipera sichuanensis Guo & Wang, 2011, sp. nov.
No full textSinovipera sichuanensis sp. nov. Figs. 3–7 Trimeresurus stejnegeri (non Trimeresurus stejnegeri Schmidt, 1925).—Zhao et al. (2002: 233). Trimeresurus albolabris (non Trimeresurus albolabris Gray, 1842).— Zhao (2006: 140). Holotype. YBU 071077, an adult female (Figs. 3–4) from Hejiang County, Sichuan Province, China. It was collected near a small river in the forest by a local farmer at an elevation of 1000 m above sea level in August 2007. The specimen is deposited in Yibin University. Paratype. YBU 030116, an adult female (Figs. 5–6). Collected in July 2003, from the same locality, and by the same farmer, as that of the holotype. The specimen is deposited in Yibin University. Diagnosis. As for the generic diagnosis. Description of the holotype. Adult female. Nearly uniformly green, lacking postorbital and ventrolateral stripe. Body elongated, cylindrical, and stout; head distinctly triangular and elongated, distinct from the neck; snout elongated and pointed. SVL 900 mm, TL 180 mm, ratio TL / Total length 0.167. HL 44.20 mm, HW 27.84 mm. Third supralabial = 5.06 mm high, 6.58 mm wide. Supraocular has a maximum length of 4.93 mm, maximum width of 2.57 mm. The eye is deep red in life, diameter 4.97 mm. The pupil is vertical. The distance between the rear edge of the nasal to the front edge of the eye is 17.77 mm. The tail is distinctly prehensile, with about 1 / 3 of the TL is rusty red dorsally (Fig. 3). Rostral rapeziform, invisible from above. Pit present between nostril and eye, surrounded by three scales (Fig. 4). Ten supralabials on both sides; the first separated from nasal by a distinct suture; the second the highest, forming the anterior border of the pit cavity, and separated from the nasal by two small scales that are vertically arranged; the third is the largest, separated from the eye by an elongated subocular; the fourth supralabial separated from eye by three scales, of which the upper two are in line. Nasals separated by three scales, and internasals do not touch the rostral. There are 14 cephalic scales in a line between the supraoculars. Two elongated scales are present between the eye and nostril. The temporal region and rear head scales are smooth. Body scales feebly keeled except outer four to five rows. Three preoculars, elongated, the middle and lower ones forming the border of the pit cavity. Two postoculars; one subocular, elongated. Supraoculars bordered by nine/eight scales (excluding the postoculars and preoculars). Infralabials 13 / 13, the first pair separated by the first pair of chin shields, and in contact with two pairs of chin shields. The second and third pair of infralabials touching the second chin shields. Six scales in a line between the first preventral and the posterior chin shields. Ventrals 172, plus 2 preventrals. Anal entire. Body scales 21 - 21 - 15. Scale reduction formula at the rear of the body as given below: 104 (5 + 6) 115 (4 + 5) 125 (4 + 5) 21 -------------------------- 19 -------------------------- 17 -------------------------- 15 104 (4 + 5) 113 (4 + 5) 127 (4 + 5) Subcaudals 68 pairs. Scale reduction formula in tail as given below: 10 (3 + 4) 33 (2 + 3) 8 ----------------------- 6 ----------------------- 4 11 (3 + 4) 33 (2 + 3) Description of the paratype (Figs 5–6). Adult female with SVL 1010 mm, TL 210 mm, ratio TL / Total length 0.172. HL 48.08 mm, HW 30.98 mm. Supralabials 10 on left and 12 on right. Infralabials 14 / 13, the first pair fused with first pair of chin shields. Six scales in a line between the preventral and the posterior chin shields. Ventrals 171 plus 3 preventrals. Body scales 21 - 21 - 15. Scale reduction formula at rear of body as below: 110 (5 + 6) 115 (3 + 4) 138 (4 + 5) 21 -------------------------- 19 -------------------------- 17 -------------------------- 15 108 (4 + 5) 115 (4 + 5) 134 (4 + 5) Subcaudals 68 pairs. Scale reduction formula of tail as below: 13 (3 + 4) 38 (2 + 3) 8 ----------------------- 6 ----------------------- 4 10 (3 + 4) 40 (2 + 3) All other morphological characters, including the body coloration, are consistent with those of the holotype. Etymology. The specific nomen is based on the Chinese province of Sichuan, which includes the type locality of the new species. We suggest that the common name of this new species be “Sichuan pitviper” or “Sichuan Chinese pitviper” in English. Distribution. This species is currently known only from the type locality (Figs. 1 & 7), where it is sympatric with Viridovipera stejnegeri. It is likely that the new species species also occurs in Chongqing and Guizhou. No other data on its feeding and reproduction are available.Published as part of Guo, Peng & Wang, Yuezhao, 2011, A new genus and species of cryptic Asian green pitviper (Serpentes: Viperidae: Crotalinae) from southwest China, pp. 1-14 in Zootaxa 2918 on pages 9-12, DOI: 10.5281/zenodo.20354
The charge transfer and ion formation in liquid Li-Tl alloys
No full textThe 7Li NMR Knight shift, K, and the spin-lattice relaxation time, T1, were measured for liquid Li–Tl alloys. The K decreases rapidly with the addition of Tl up to 20 at.% Tl. In the concentration from 20 to 50 at.% Tl, the K decreases only slightly and the K of 50 at.% Tl is 60% of K for the pure liquid Li. Such a decrease of K is considered as an indication for the strong charge transfer from Li to Tl. These tendencies are similar to those from previous studies for liquid Li–Ga and Li–In alloys. However, beyond 50 at.% Tl, the K increases and reaches to an almost constant value (70% of K for the pure liquid Li). Such a back donation of charge is absent for liquid Li–Ga and Li–In alloys. It is considered that the tendency of the formation of ionic structural unit for liquid Li–Tl alloys is slightly weaker compared with the cases of liquid Li–Ga and Li–In alloys. The T1 is also discussed with the relation to the Knight shift and the electronic properties
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