209,657 research outputs found
Performance Evaluation of Distributed-Antenna Communications Systems Using Beam-Hopping
No full textDigital beamforming (DBF) techniques are capable of improving the performance of communications systems significantly. However, if the transmitted signals are conflicted with strong interference, especially, in the direction of the transmitted beams , these directional jamming signals will severely degrade the system performance. In order to efficiently mitigate the interference of the directional jammers, in this contribution a beam-hopping (BH) communications scheme is proposed. In the proposed BH communications scheme, only one pair of the beams is used for transmission and it hops from one to the next according to an assigned BH pattern. In this contribution a range of expressions in terms of the average SINR performance have been derived, when both the uplink and downlink are considered. The average SINR performance of the proposed BH scheme and that of the conventional single-beam (SB) as well as multiple-beam (MB) assisted beam-processing schemes have been investigated. Our analysis and results show that the proposed BH scheme is capable of efficiently combating the directional jamming, with the aid of utilizing the directional gain of the beams generated by both the transmitter and the receiver. Furthermore, the BH scheme is capable of reducing the intercept probability of the communications. Therefore, the proposed BH scheme is suitable for communications, when several distributed antenna arrays are available around a mobile
A new cohesive model for simulating delamination propagation in composite laminates under transverse loads
No full textIn this paper, we propose a new cohesive model to stably and accurately simulate the\ud
delamination propagations in composite laminates under quasi-static and low-velocity\ud
impact transverse loads using comparatively coarse meshes. In this model, a pre-softening\ud
zone ahead of the existing traditional softening zone is proposed. In this pre-softening zone,\ud
the initial stiffnesses and the interface strengths at the integration points of cohesive elements\ud
are gradually reduced as the corresponding effective relative displacements at these\ud
points increase. However, the onset displacement corresponding to the onset damage is\ud
not changed in this model. Moreover, the fracture toughness of materials for determining\ud
the final displacement of complete decohesion is kept constant. This cohesive model is\ud
implemented in the explicit time integration scheme combined with a powerful threedimensional\ud
(3D) hybrid finite element for evaluating the delamination propagations on\ud
interfaces in composite laminates. A DCB problem is employed to analyze the characteristics\ud
of the present cohesive model. In order to reduce the computational cost for dealing\ud
with more complex problems, a stress-based criterion is also adopted in our numerical\ud
model for evaluating various in-plane damages, such as matrix cracks, fiber breakage,\ud
etc. Finally, two experimental examples are employed to illustrate the validity of the present\ud
approach
TCF_Relf2D: Stochastic inversion of Gaussian random media using transverse coherence functions for reflected waves: theory and method
No full textThis is the Matlab package for TCF_Relf2D, for Hu, H. and Zheng, Y., Stochastic inversion of Gaussian random media using transverse coherence functions for reflected waves: theory and method, JGR Solid Earth
Apecholinus imitator Smetana & Hu 2019
No full textApecholinus imitator Smetana & Hu, 2019 (Figs. 5–6) Material examined. TAIWAN: Pingtung County: 1 spec., Tahanshan (± ÀƜ), 25.IV.2017. leg. B.-X. Guo (TARI); 1 female, Chun-jih, Ta-han shan, ± ÀƜ, 1350m, 2019,V-13 (Night), Y.- T. Chung Leg. CCCC (FSHc); 1 female, Majia Forest Trail (ṞxIJǎ), Majia To., 28-VI-2017, leg. R. H. Liu (FSHc); 1 spec., CCCC, Tahanshan (± ÀƜ), 15.IV.2019. leg. Y.- T. Chung (TARI). Description. For male description see Smetana & Hu (2019). Female. Genital segment. Tergite 10 (Fig. 6) obviously different from male tergite 10. Apical portion of female tergite 10 markedly narrow and elongated, with narrow acute apical portion; setae are relatively concentrated on the apex. Diagnosis. Apecholinus imitator can be distinguished from all other species of Apecholinus in Taiwan by the golden-yellow tomentose setae on the body. An undescribed species of Apecholinus in Taiwan is similar to this species but it currently known only from a single female, so I refrain from describing it until male specimens are found. The patches of golden-yellow tomentose pubescence on the elytra of Ap. imitator are much larger than that of the undescribed species. Bionomics. Based on an import of locality name into Google Earth from collection data (Smetana & Hu 2019 and this study), the species occurs from 800–1700 m. One specimen of Ap. imitator was collected by pitfall trap but nothing known about the habitat the traps were set in; some specimens of Ap. imitator were attracted to an LED flashlight in the evening on a forest trail (Smetana & Hu 2019). Distribution. Apecholinus imitator is at present known from central and southern Taiwan including Nantou County, Taitung County and Pingtung County (Smetana & Hu 2019, this study). Remarks. Up to the present, the morphology of females in Apecholinus is poorly known. So far, only females of Ap. fraternus (see Smetana 2018), Ap. liui (He & Zhou, 2017) (see He & Zhou 2017) and Ap. kaiseri Bernhauer, 1933 (see Smetana 2003) had been described and female tergite 10 of these species is similar to that of the male. However, the apical portion of tergite 10 of Ap. imitator is much narrower and more elongate in females than in males.Published as part of Hu, Fang-Shuo, 2020, New distributional records of Staphylinina in Taiwan, including a new species of Miobdelus Sharp (Coleoptera: Staphylinidae: Staphylininae: Staphylinini), pp. 334-360 in Zootaxa 4768 (3) on page 337, DOI: 10.11646/zootaxa.4768.3.2, http://zenodo.org/record/378403
Chen, M.-J., Han, Y.-R., Hu, J.-X., Liu, Y.-J. & Huang, B. (2023) Tolypocladium rhizomatum sp. nov.: an endophytic species isolated from the rhizome of Polygonatum cyrtonema. Phytotaxa 606 (3): 201-210.
No full textChen, M.-J., Han, Y.-R., Hu, J.-X., Liu, Y.-J., Huang, B. (2023): Chen, M.-J., Han, Y.-R., Hu, J.-X., Liu, Y.-J. & Huang, B. (2023) Tolypocladium rhizomatum sp. nov.: an endophytic species isolated from the rhizome of Polygonatum cyrtonema. Phytotaxa 606 (3): 201-210. Phytotaxa 607 (1): 114-114, DOI: 10.11646/phytotaxa.607.1.10, URL: http://dx.doi.org/10.11646/phytotaxa.607.1.1
Agelosus auricomus Smetana & Hu 2019
No full textAgelosus auricomus Smetana & Hu, 2019 (Figs. 3, 50) Material examined. TAIWAN: New Taipei City: 1 female, Guishan (ƟƜ), Wulai Dist., 24.9021, 121.5510, ca. 80m, 13-IV-2012, leg. L. C. Shih (FSHc). Nantou County: 1 spec., CCCC, Shihmenshan (ƂḋƜ), 03.III.2019. leg. S.-P. Wu (TARI). Yilan County: 1 male, Fushan Botanical Garden (AEƜ ḆṄṞ), Yunnan To., 26-II-2020, leg. S. S. Lu (FSHc). Diagnosis. Agelosus auricomus is the only species of the genus in Taiwan. It can be distinguished from most Staphylinina in Taiwan by the mandibles each with a subdental indentation. However, this character convergently evolved in the genus Nelmanwaslus Smetana, 2006. So far, only N. ornatus Smetana, 2006 has been found in Taiwan and is newly reported in this paper. Agelosus auricomus can be easily distinguished from N. ornatus by the patches of golden-yellow tomentose pubescence on the elytra (Fig. 3). Bionomics. Based on an import of locality name into Google Earth from collection data (Smetana & Hu 2019), Ag. auricomus occurs from 20– 800 m. Apparently, the species only occurs in the lowlands or low mountains. The specimen from Guishan was collected from the foot of a mountain near Nanshi River (ĦBữ). Smetana & Hu (2019) reported a specimen that was collected from under a stone in a valley in mixed wood forest. Distribution. Agelosus auricomus is at present known from Taiwan, including Nantou County, New Taipei City, Taipei City and Yilan County (Smetana & Hu 2019 and this study). The additional specimen from Nantou indicates that this species is perhaps widespread in Taiwan. Apecholinus fraternus Fairmaire, 1891 (Fig. 4) Material examined. TAIWAN: Hsinchu County: 1 spec., Talutrail (±ẘIJǎ), 01.VIII.2015, leg. Y.-L. Lin (TARI). Nantou County: 1 male, Meifeng (đø), Renai To., 05-VI-2019, leg. W. Z. Wang (FSHc). Diagnosis. Apecholinus fraternus can be distinguished from all other species of Apecholinus in Taiwan by the lack of golden-yellow or grey tomentose pubescence on the body. Bionomics. Based on an import of locality name into Google Earth from collection data (Hayashi 1978, Smetana 2018, Smetana & Hu 2019), Ap. fraternus occurs from 1400–2600 m in Taiwan. Some specimens of this species were collected by pitfall traps, but nothing known about the habitat the traps were set in (Smetana 2018, Smetana & Hu 2019). Smetana & Hu (2019) reported a specimen collected from under a rock near a creek. Distribution. Apecholinus fraternus is widespread in mainland China including Guangxi, Guizhou, Henan, Hubei, Hunan, Shaanxi, Sichuan and Yunnan. The species also widespread in Taiwan including Chiayi County, Hsinchu County, Hualien County, Nantou County and Taichung City (Smetana 2018, Smetana & Hu 2019). The specimen from Hsinchu represents the first specimen from northern Taiwan. Remarks. The name ‘ Agelosus fraternus ’ in the ‘Geographical distribution’ section of Ap. fraternus in Smetana & Hu (2019) should be corrected to ‘ Apecholinus fraternus ’.Published as part of Hu, Fang-Shuo, 2020, New distributional records of Staphylinina in Taiwan, including a new species of Miobdelus Sharp (Coleoptera: Staphylinidae: Staphylininae: Staphylinini), pp. 334-360 in Zootaxa 4768 (3) on pages 336-337, DOI: 10.11646/zootaxa.4768.3.2, http://zenodo.org/record/378403
HU Protein Induces Incoherent DNA Persistence Length
No full textHU is a highly conserved protein that is believed to play an important role in the architecture and dynamic compaction of bacterial DNA. Its ability to control DNA bending is crucial for functions such as transcription and replication. The effects of HU on the DNA structure have been studied so far mainly by single molecule methods that require us to apply stretching forces on the DNA and therefore may perturb the DNA-protein interaction. To overcome this hurdle, we study the effect of HU on the DNA structure without applying external forces by using an improved tethered particle motion method. By combining the results with DNA curvature analysis from atomic force microscopy measurements we find that the DNA consists of two different curvature distributions and the measured persistence length is determined by their interplay. As a result, the effective persistence length adopts a bimodal property that depends primarily on the HU concentration. The results can be explained according to a recently suggested model that distinguishes single protein binding from cooperative protein binding.Imaging Science and TechnologyApplied Science
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