Discussion on origin of Pn velocity variation in China and adjacent region

2004 ◽  
Vol 17 (1) ◽  
pp. 1-11 ◽  
Author(s):  
Shun-ping Pei ◽  
Zhong-huai Xu ◽  
Su-yun Wang
Keyword(s):  
Velocity Variation ◽  
Adjacent Region ◽  
Pn Velocity

Precipitation on Low Angle Boundaries in Al-Zn-Mg

1980 ◽  
Vol 38 ◽  
pp. 374-375
Author(s):  
Diane M. Vanderwalker
Keyword(s):  
Grain Boundaries ◽  
High Strength ◽  
Boundary Structure ◽  
Aircraft Industry ◽  
Precipitate Free Zone ◽  
High Angle ◽  
Adjacent Region ◽  
Free Zone ◽  
Widespread Interest

There is a widespread interest in understanding the properties of Al-base alloys so that progress can be made toward extending their present applications in the aircraft industry. Al-Zn-Mg is precipitation hardened to gain its high strength; however, during aging the formation of heterogeneous precipitates on the grain boundaries creates a precipitate-free zone in the adjacent region. Since high angle grain boundaries are not easily characterized, it is difficult to establish a relationship between the precipitate and the boundary structure. Therefore, this study involves precipitation on low angle grain boundaries where the boundary and the precipitate can be fully analyzed.

scholarly journals The Zn-finger of Saccharomyces cerevisiae Rad18 and its adjacent region mediate interaction with Rad5

2021 ◽  
Author(s):  
Orsolya Frittmann ◽  
Vamsi K Gali ◽  
Miklos Halmai ◽  
Robert Toth ◽  
Zsuzsanna Gyorfy ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Dna Damage ◽  
Ubiquitin Ligase ◽  
Dna Lesions ◽  
Template Switching ◽  
Adjacent Region ◽  
Yeast Two Hybrid ◽  
Replication Complex ◽  
Two Hybrid

Abstract DNA damages that hinder the movement of the replication complex can ultimately lead to cell death. To avoid that, cells possess several DNA damage bypass mechanisms. The Rad18 ubiquitin ligase controls error-free and mutagenic pathways that help the replication complex to bypass DNA lesions by monoubiquitylating PCNA at stalled replication forks. In Saccharomyces cerevisiae, two of the Rad18 governed pathways are activated by monoubiquitylated PCNA and they involve translesion synthesis polymerases, whereas a third pathway needs subsequent polyubiquitylation of the same PCNA residue by another ubiquitin ligase the Rad5 protein, and it employs template switching. The goal of this study was to dissect the regulatory role of the multidomain Rad18 in DNA damage bypass using a structure-function based approach. Investigating deletion and point mutant RAD18 variants in yeast genetic and yeast two-hybrid assays we show that the Zn-finger of Rad18 mediates its interaction with Rad5, and the N-terminal adjacent region is also necessary for Rad5 binding. Moreover, results of the yeast two-hybrid and in vivo ubiquitylation experiments raise the possibility that direct interaction between Rad18 and Rad5 might not be necessary for the function of the Rad5 dependent pathway. The presented data also reveal that yeast Rad18 uses different domains to mediate its association with itself and with Rad5. Our results contribute to better understanding of the complex machinery of DNA damage bypass pathways.

scholarly journals Anomalous azimuthal variations with 360° periodicity of Rayleigh phase velocities observed in Scandinavia

2020 ◽  
Vol 224 (3) ◽  
pp. 1684-1704
Author(s):  
Alexandra Mauerberger ◽  
Valérie Maupin ◽  
Ólafur Gudmundsson ◽  
Frederik Tilmann
Keyword(s):  
Seismic Anisotropy ◽  
Broad Band ◽  
Shear Velocity ◽  
Velocity Variation ◽  
The South ◽  
Study Region ◽  
Lithospheric Thickness ◽  
Phase Velocities ◽  
The North ◽  
Southern Norway

SUMMARY We use the recently deployed ScanArray network of broad-band stations covering most of Norway and Sweden as well as parts of Finland to analyse the propagation of Rayleigh waves in Scandinavia. Applying an array beamforming technique to teleseismic records from ScanArray and permanent stations in the study region, in total 159 stations with a typical station distance of about 70 km, we obtain phase velocities for three subregions, which collectively cover most of Scandinavia (excluding southern Norway). The average phase dispersion curves are similar for all three subregions. They resemble the dispersion previously observed for the South Baltic craton and are about 1 per cent slower than the North Baltic shield phase velocities for periods between 40 and 80 s. However, a remarkable sin(1θ) phase velocity variation with azimuth is observed for periods >35 s with a 5 per cent deviation between the maximum and minimum velocities, more than the overall lateral variation in average velocity. Such a variation, which is incompatible with seismic anisotropy, occurs in northern Scandinavia and southern Norway/Sweden but not in the central study area. The maximum and minimum velocities were measured for backazimuths of 120° and 300°, respectively. These directions are perpendicular to a step in the lithosphere–asthenosphere boundary (LAB) inferred by previous studies in southern Norway/Sweden, suggesting a relation to large lithospheric heterogeneity. In order to test this hypothesis, we carried out 2-D full-waveform modeling of Rayleigh wave propagation in synthetic models which incorporate a steep gradient in the LAB in combination with a pronounced reduction in the shear velocity below the LAB. This setup reproduces the observations qualitatively, and results in higher phase velocities for propagation in the direction of shallowing LAB, and lower ones for propagation in the direction of deepening LAB, probably due to the interference of forward scattered and reflected surface wave energy with the fundamental mode. Therefore, the reduction in lithospheric thickness towards southern Norway in the south, and towards the Atlantic ocean in the north provide a plausible explanation for the observed azimuthal variations.

Analytical predictor–corrector entry guidance for hypersonic gliding vehicles

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Huatao Chen ◽  
Kun Zhao ◽  
Juan L.G. Guirao ◽  
Dengqing Cao
Keyword(s):  
Feedback Control ◽  
Velocity Variation ◽  
Analytical Relation ◽  
Aerodynamic Load ◽  
Quasi Equilibrium ◽  
Bank Angle ◽  
Entry Guidance ◽  
Guidance Algorithm ◽  
Predictor Corrector ◽  
Guidance Problem

AbstractFor the entry guidance problem of hypersonic gliding vehicles (HGVs), an analytical predictor–corrector guidance method based on feedback control of bank angle is proposed. First, the relative functions between the velocity, bank angle and range-to-go are deduced, and then, the analytical relation is introduced into the predictor–corrector algorithm, which is used to replace the traditional method to predict the range-to-go via numerical integration. To eliminate the phugoid trajectory oscillation, a method for adding the aerodynamic load feedback into the control loop of the bank angle is proposed. According to the quasi-equilibrium gliding condition, the function of the quasi-equilibrium glide load along with the velocity variation is derived. For each guidance period, the deviation between the real-time load and the quasi-equilibrium gliding load is revised to obtain a smooth reentry trajectory. The simulation results indicate that the guidance algorithm can adapt to the mission requirements of different downranges, and it also has the ability to guide the vehicle to carry out a large range of lateral maneuvers. The feedback control law of the bank angle effectively eliminates the phugoid trajectory oscillation and guides the vehicle to complete a smooth reentry flight. The Monte Carlo test indicated that the guidance precision and robustness are good.

scholarly journals Out of the Qinghai-Tibetan Plateau (QTP) and rapid radiation across Eurasia for Allium section Daghestanica (Amaryllidaceae)

AoB Plants ◽  
2021 ◽  
Author(s):  
Min-Jie Li ◽  
Huan-Xi Yu ◽  
Xian-Lin Guo ◽  
Xing-Jin He
Keyword(s):  
Evolutionary History ◽  
Divergence Time ◽  
Time Estimation ◽  
Adjacent Region ◽  
Rapid Radiation ◽  
Divergence Time Estimation ◽  
Species Diversification ◽  
The Third ◽  
Evolutionary Line ◽  
History Of

Abstract The disjunctive distribution (Europe-Caucasus-Asia) and species diversification across Eurasia for the genus Allium sect. Daghestanica has fascinating attractions for researchers aiming to understanding the development and history of the modern Eurasia flora. However, no any studies have been carried out to address the evolutionary history of this section. Based on the nrITS and cpDNA fragments (trnL-trnF and rpl32-trnL), the evolutionary history of the third evolutionary line (EL3) of the genus Allium was reconstructed and we further elucidate the evolutionary line of sect. Daghestanica under this background. Our molecular phylogeny recovered two highly supported clades in sect. Daghestanica: the Clade I includes Caucasian-European species and Asian A. maowenense, A. xinlongense and A. carolinianum collected in Qinghai; the Clade II comprises Asian yellowish tepal species, A. chrysanthum, A. chrysocephalum, A. herderianum, A. rude and A. xichuanense. The divergence time estimation and biogeography inference indicated that Asian ancestor located in the QTP and the adjacent region could have migrated to Caucasus and Europe distributions around the Late Miocene and resulted in further divergence and speciation; Asian ancestor underwent the rapid radiation in the QTP and the adjacent region most likely due to the heterogeneous ecology of the QTP resulted from the orogeneses around 4–3 Mya. Our study provides a picture to understand the origin and species diversification across Eurasia for sect. Daghestanica.

Accurate Simulation of the Four Modes of Post-Die Extrudate Shape Distortion

2021 ◽  
Vol 36 (1) ◽  
pp. 69-78
Author(s):  
M. Gupta
Keyword(s):  
Layer Structure ◽  
Die Design ◽  
Velocity Variation ◽  
Shape Distortion ◽  
Exit Velocity ◽  
Extrusion Die ◽  
Combined Flow ◽  
Extruded Product ◽  
Simulation Results ◽  
Extrudate Distortion

Abstract A combined flow, thermal and structural analysis is employed to simulate post-die extrudate distortion in different profile dies. All four factors which can cause extrudate distortion, namely, nonuniform exit velocity distribution, extrudate shrinkage, extrudate draw down, and deformed shape of the calibrator or sizer profile, are simulated. To analyze the effect of exit velocity variation on extrudate distortion, the parameterized geometry of a simple profile die is optimized using an extrusion die optimization software. The simulation results presented for a bi-layer profile die successfully demonstrate how gradually changing profile shape in successive calibrators/sizers can be used to simplify the die design for extrusion of complex profiles. The predicted extrudate shape and layer structure for the bi-layer die are found to accurately match with those in the extruded product.

scholarly journals An Ultrahigh-Sensitivity Graphene Resonant Gyroscope

Nanomaterials ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1890
Author(s):  
Yang Lu ◽  
Zhan-She Guo ◽  
Shang-Chun Fan
Keyword(s):  
Angular Velocity ◽  
High Sensitivity ◽  
Velocity Variation ◽  
Beam Length ◽  
Sensing Element ◽  
Finite Element Software ◽  
Resonant Beam ◽  
Frequency Output ◽  
Length Width ◽  
Ultrahigh Sensitivity

In this study, a graphene beam was selected as a sensing element and used to form a graphene resonant gyroscope structure with direct frequency output and ultrahigh sensitivity. The structure of the graphene resonator gyroscope was simulated using the ANSYS finite element software, and the influence of the length, width, and thickness of the graphene resonant beam on the angular velocity sensitivity was studied. The simulation results show that the resonant frequency of the graphene resonant beam decreased with increasing the beam length and thickness, while the width had a negligible effect. The fundamental frequency of the designed graphene resonator gyroscope was more than 20 MHz, and the sensitivity of the angular velocity was able to reach 22,990 Hz/°/h. This work is of great significance for applications in environments that require high sensitivity to extremely weak angular velocity variation.

scholarly journals Monitoring Master Swimmers’ Performance and Active Drag Evolution along a Training Mesocycle

2021 ◽  
Vol 18 (7) ◽  
pp. 3569
Author(s):  
Henrique P. Neiva ◽  
Ricardo J. Fernandes ◽  
Ricardo Cardoso ◽  
Daniel A. Marinho ◽  
J. Arturo Abraldes
Keyword(s):  
Aerobic Training ◽  
Training Period ◽  
Velocity Variation ◽  
Hydrodynamic Drag ◽  
Swimming Training ◽  
Front Crawl ◽  
Maximal Intensity ◽  
Before And After ◽  
Active Drag

This study aimed to analyze the effects of a swimming training mesocycle in master swimmers’ performance and active drag. Twenty-two 39.87 ± 6.10 year-old master swimmers performed a 25 m front crawl at maximal intensity before and after a typical four-week training mesocycle. Maximum, mean and minimum speeds, speed decrease and hip horizontal intra-cyclic velocity variation were assessed using an electromechanical speedometer, and the active drag and power to overcome drag were determined using the measuring active drag system. Maximum, mean and minimum front crawl speeds improved from pre- to post-training (mean ± 95% CI: 3.1 ± 2.8%, p = 0.04; 2.9 ± 1.6%, p = 0.01; and 4.6 ± 3.1%, p = 0.01; respectively) and the speed decrease along the 25 m test lowered after the training period (82.5 ± 76.3%, p = 0.01). The training mesocycle caused a reduction in the active drag at speeds corresponding to 70% (5.0 ± 3.9%), 80% (5.6 ± 4.0%), and 90% (5.9 ± 4.0%), but not at 100% (5.9 ± 6.7%), of the swimmers’ maximal exertions in the 25 m test. These results showed that four weeks of predominantly aerobic training could improve master swimmers’ performance and reduce their hydrodynamic drag while swimming mainly at submaximal speeds.

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