bluuebunny/crossref_metadata_2025_split huggingface dataset:
Preferential activation of proprioceptive and cutaneous sensory fibers compared to motor fibers during cervical transcutaneous spinal cord stimulation: a computational study
Authors: de Freitas Roberto M , Capogrosso Marco , Nomura Taishin , Milosevic Matija 
Published: April 2022

Abstract

Objective. Cervical transcutaneous spinal cord stimulation (tSCS) is a promising technology that can support motor function recovery of upper-limbs after spinal cord injury. Its efficacy may depend on the ability to recruit sensory afferents, conveying excitatory inputs onto motoneurons. Therefore, understanding its physiological mechanisms is critical to accelerate its development towards clinical applications. In this study, we used an anatomically realistic cervical tSCS computational model to compare α-motor, Aα-sensory, and Aβ-sensory fiber activation thresholds and activation sites. Approach. We developed a 3D geometry of the cervical body and tSCS electrodes with a cathode centred at the C7 spinous process and an anode placed over the anterior neck. The geometrical model was used to estimate the electric potential distributions along motor and sensory fiber trajectories at the C7 spinal level using a finite element method. We implemented dedicated motor and sensory fiber models to simulate the α-motor and Aα-sensory fibers using 12, 16, and 20 µm diameter fibers, and Aβ-sensory fibers using 6, 9, and 12 µm diameter fibers. We estimated nerve fiber activation thresholds and sites for a 2 ms monophasic stimulating pulse and compared them across the fiber groups. Main results. Our results showed lower activation thresholds of Aα- and Aβ-sensory fibers compared with α-motor fibers, suggesting preferential sensory fiber activation. We also found no differences between activation thresholds of Aα-sensory and large Aβ-sensory fibers, implying their co-activation. The activation sites were located at the dorsal and ventral root levels. Significance. Using a realistic computational model, we demonstrated preferential activation of dorsal root Aα- and Aβ-sensory fibers compared with ventral root α-motor fibers during cervical tSCS. These findings suggest high proprioceptive and cutaneous contributions to neural activations during cervical tSCS, which inform the underlying mechanisms of upper-limb functional motor recovery.
Stability Analysis of Rotor with a Spline Coupling
Authors: Wang Tong , Wang Yankai , Liu Meiru , Zhong Zhicai 
Published: April 2022

Abstract
The spline coupling is widely used in aero-engines. Once the spline coupling fails, it will cause great damage to the engine. In this paper, the stability of a rotor with a spline coupling was studied. The internal damping instability model of the rotor with spline coupling is deduced, and the instability mechanism is explored. The stability boundary is analyzed by using the R-H criterion. The mechanism of rotor instability is analyzed by simulation. An experimental system of rotors with different structural parameters of spline coupling was built. The influence of the positioning surface clearance on the stability was analyzed. The modeling results show that the internal friction of the spline coupling will introduce additional damping and anti-symmetrical cross stiffness to the rotor, the additional damping will reduce the vibration response, and the anti-symmetrical cross stiffness will cause the rotor to become unstable. The simulation and experimental results show that the rotor system will not be unstable when the two positioning surfaces of the spline coupling are in an interference fit. When one of the positioning surfaces is a clearance fit and the other is an interference fit, the internal friction will cause the rotor to become unstable. The instability threshold speed is higher than the first-order critical speed. At the same time, due to the additional damping introduced by the sleeve tooth structure, there will be a transition stage of instability. At this time, the rotor will vibrate with sub-harmonic components, but the vibration amplitude of the rotor will decrease. When the two positioning surfaces are clearance fit, the rotor is unstable and the amplitude increases suddenly. The obtained instability characteristics of the rotor with spline coupling have important value for the instability fault diagnosis, and provide help for the stability control.
Research on drag reduction and heat prevention performance of spike with the channel concept for hypersonic blunt body
Authors: Wang Zi-yu , Fang Shu-zhou , Guo Jian , Ni Zi-jian , Xu Yang 
Published: April 2022

Abstract
To answer the difficulties of drag reduction and heat protection for hypersonic vehicles, a new type of a spike with a channel entrance at the head and a lateral outlet was devised. When contrasted to a solid spike, once the channel is added, the lateral exhaust pulls the separated shock wave away from the spike, reducing the strength of the reattached shock wave and dramatically enhancing heat resistance. In this study, the affecting features of the new idea model are investigated. The findings show that the larger the half-angle of channel convergence, the better the model’s overall drag reduction and heat prevention effectiveness. In the research range, the model with a 60° convergence half angle delivers the best overall advantage in terms of drag reduction and heat prevention. The total resistance of the model was reduced by 14.44 %, and the peak heat flux of the blunt-body wall was reduced by 33.84 % compared to the solid spike.
Design and Analysis of Sectional Crossbeam Based on Finite Element Method
Authors: Chen Zhong-qing , Zhu Yi-sheng , Wang Yi-fei 
Published: April 2022

Abstract
In order to solve the problems such as high die cost and difficult casting of long span and super-long Span Crossbeam, this paper proposes to design and cast the crossbeam in sections. But whether the sectional beam can achieve the dynamic characteristics of the integral crossbeam is studied through the combination of experiment and finite element simulation, the results show that the dynamic characteristics of the sectional beam and the integral crossbeam tend to be the same.
Thermal stability measurement of terminal face relative pose for complex structure based on coordinate measuring machine
Authors: Tang Xiaojun , Liu Jialin , Yu Wentao , Hui Tianli , Han Jingzhen , Tian Xin 
Published: April 2022

Abstract
The coordinate measuring machine has high measurement accuracy, but it is only suitable for the precise measurement of the geometric size of the component in the normal temperature environment, and some complex structures need to assess the stability of the terminal face relative pose in the high and low temperature environment. In order to apply the high-precision measurement of the coordinate measuring machine to the thermal stability evaluation of the relative pose of the terminal face of complex structures, an extended temperature control method based on the coordinate measuring machine is proposed. The method realizes the loading control of the temperature environment of the specimen by the mobile temperature control module and the temperature control medium circulation module. The flexible connection mode is used between the temperature control module and the temperature control medium circulation module to reduce the influence of mechanical vibration on the measurement accuracy. The mixing fan and the temperature control medium dryer are installed in the pipeline to avoid frosting and dewing in the temperature control box and ensure the uniform distribution of the temperature field, so as to realize the accurate measurement of the relative pose of the terminal face of the complex structure under the high and low temperature environment by the coordinate measuring machine. The method is applied to the thermal stability test of the relative pose of the end face of a joint component, and the test results are good, which provides a new idea for the extended application of coordinate measuring machines.
Research on Abnormal Geometric Similarity Design Method of a Missile with Tail Rudder Model in High Speed Wind Tunnel
Authors: Chen Jianzhong 
Published: April 2022

Abstract
Geometric similarity is an important similarity laws for the experimental study on aerodynamic characteristics of wind tunnel models. General aspect the ratio of missile body length to rudder surface aspect length is large. The test model is designed according to the complete geometric similarity scale. It is often difficult to match the length aspect ratio size in the limited space of the wind tunnel test section. Based on this problem, the abnormal geometric similarity design method of the missile body under the condition of fixed tail rudder is studied by numerical simulation. The results show that When truncated to 0.625, 0.7, 0.8 and 0.9 times the original projectile length, the change of the inflow conditions at the leading edge of the rudder surface is small, which can meet the research needs of the aerodynamic characteristics of the tail rudder, and lay a theoretical foundation for the design of relevant wind tunnel test models.
Research on guided wave propagation characteristics of C/C thermal protection structures
Authors: Lu Xulong , Qiu Lei , Yuan Shenfang , Zheng Hui 
Published: April 2022

Abstract
Thermal protection structures (TPS) are the key component in the design and manufacture of the reusable launch vehicle. The probability of failure of TPS in an aerodynamic thermal environment during reentry is much higher than that of ordinary structures. There is an urgent need to develop a structural health monitoring (SHM) method that can achieve rapid diagnostic for TPS to realize the high reliability and maintainability of the reusable launch vehicle. Hence, this paper aims at the typical TPS made of C/C composite material, the feasibility of SHM methods based on the active piezoelectric guided wave was studied and verified. And the propagation characteristics of guided wave in the TPS such as the multi-mode, the signal frequencies of monitoring and the effects of material anisotropy on the propagation characteristics of the guided wave were analyzed. Then, a guided wave monitoring experiment of C/C TPS with simulation damage was carried out, and the variation of a guided wave under different damage levels was analyzed from the aspects of amplitude, phase, damage scattering and damage index. The results show that the SHM methods based on active piezoelectric guided wave can effectively monitor the damage and damage expansion on the surface of C/C TPS.
Soft connection failure analysis and optimization design of transparent parts based on flexible force sensitivity
Authors: Kan Yan , Zhang Ping , Zhang Jian , Huang Renchang , Wang Pengfei 
Published: April 2022

Abstract
Scanning electron microscopy (SEM) was used to carry out macro and micro detection on the samples of soft bonding failure of aerial transparent parts. Combined with the observation results, a flexible force-sensing system was used to realize 2d and 3D imaging and data acquisition of the pressure distribution in the pressure process, and the relationship between the bonding strength and pressure of J-189 polyurethane adhesive was analyzed. The results show that there is a wide range of pressure out of tolerance in the pressure clamping process widely used in domestic industrial sectors. It will cause the debonding phenomenon of block and strip, etc. Finally, according to the analysis results, a pressure application scheme of using a manipulator automation device to replace the traditional mechanical fixture is proposed, which provides an improvement idea for improving the reliability and efficiency of the soft connection.
Automated Path Planning for unmanned aerial vehicle in Urban Dynamic Area
Authors: Ma Yinsong , Liu Guangcai 
Published: April 2022

AbstractThis paper addresses the path planning and autonomous obstacle avoidance problem of UAVs in urban dynamic area. A flight path planning strategy for UAVs in complex urban environments is proposed.First, the A* algorithm is used to construct a desired global path in a 3D static environment, which is used as the static reference path for dynamic obstacle avoidance below.The environmental and the key points of algorithm are also elaborated. In this paper, the dynamic obstacles are divided into three categories, then, in order to avoid the collision between dynamic obstacles and static optimal paths, two strategies to achieve local online path adjustment are proposed. Finally, the seven order minimum snap trajectories generation based on piecewise polynomials is utilized to smooth the flight path.We can obtain a smooth trajectory based on UAV dynamics and safety. The simulation results verify the effectiveness of the proposed UAV path planning strategy in the dynamic and complex urban area.
Development of visual helicopter emergency rescue system
Authors: Hao JingLong , Wang YongHu , Zheng Ran 
Published: April 2022

Abstract
Helicopter rescue is an important part of emergency rescue syste m, an d is oft en ca r r ie d out under complex terrain and low-visibility meteorological conditions. In order to ensure the safety of helicopter flight and the timely and efficient implementation of emergency rescue, it is necessary to establish a visual emergency rescue system. This paper selects Chongqing as the reference city, and it is preliminarily planned to take “GeoSim” as the 3D simulation platform, combined with the secondary development technology of geographic information system (GIS). According to the current flight performance of helicopters, and through the analysis of obstacle crossing, the intelligent algorithm can realize the visual simulation demonstration of single helicopter rescue system and multi-helicopter rescue system along the optimized path and user-defined path, and give the quality evaluation of emergency rescue drills, as well as the suggestions of the best emergency rescue plan.
A Two-Stage Mass-to-drag Ratio Estimation Algorithm for Reentry Vehicles
Authors: Guo Xin , Chen Defeng , Cao Huawei , Zhang Shuo 
Published: April 2022

Abstract
Ballistic target tracking and identification is a key task for missile defense systems. A vital problem in ballistic target identification is how to estimate the target mass-to-drag ratio fast and accurately. The reentry phase of a ballistic missile is the last stage of its flight, and the reentry trajectory is significantly affected by the atmospheric drag. Based on the constraints of space flight dynamics, this paper proposes a two-stage algorithm to estimate the mass-to-drag ratio. This algorithm first estimates the position and velocity of the target in the free flight stage by using the least-squares method, and then estimates the mass-to-drag ratio of the target by using the radial range measurements from the reentry stage. Several trajectories of a ballistic target under different mass-to-drag ratios are simulated, and the proposed algorithm is verified using these simulated trajectories.
Effects of climate and soil properties on regional differences in nitrogen use efficiency and reactive nitrogen losses in rice
Authors: Cai Siyuan , Zhao Xu , Yan Xiaoyuan 
Published: April 2022

Abstract
Nitrogen (N) use efficiency worldwide varies greatly due to climate, agronomic, and soil factors. However, the information on individual effects of these factors on N use efficiency is crucial but has remained scanty. Given that climate cannot be regulated, understanding the relative importance of fertilizer and soil variations on regional differences in N use efficiency is critical. Here, we constructed a database of 302 studies from 1986 to 2020 in East and Northeast China to determine the effects of climate, soil properties, and fertilizer N (FN) rate on variations in N use efficiency (agronomic efficiency (AE), apparent recovery efficiency (RE), physiological efficiency (PE), N harvest index, partial factor productivity), N surplus, grain N content, and reactive N (Nr) losses (N2O emissions, NH3 volatilization, Nr leaching, and runoff). Rice yield was comparable between two regions under farmers’ N practices, yet the N input was considerably higher in East China. All indices of N use efficiency, except RE, are higher in Northeast China. Differences in AE were dominated by the ability of the plant to mobilize N (PE) rather than N uptake (RE), FN, or Nr loss. Soil properties and FN related to optimizable N management accounted for 29% (RE), 39% (PE), and 43% (Nr losses) of the variations, of which key factors as pH showed a negative effect while available N (AN) correlated positively to the N use efficiency. To realize high N use efficiency, pivotal effects of pH, AN, and FN on N use efficiency under certain climate zone should be considered.
Prediction and management of household solid waste generation during COVID-19 pandemic in Bandung City using system dynamics model
Authors: Sunaryani A 
Published: April 2022

Abstract
WHO declared a novel coronavirus in humans as Coronavirus Disease 2019 (COVID-19) on February 2020, and Indonesia as well as Bandung City have been suffering from COVID-19 since the first case in March, 2020. Currently, the outbreak of COVID-19 has occurred for more than a year. The COVID-19 pandemic had a severe impact on the environment, like the enhancement of household solid waste as a result of work and school from home policies to decrease the rates of COVID-19 cases. This study aimed to predict the amount of household solid waste generation and analyze the waste management during COVID-19 in Bandung City using a system dynamics model. Data for model input was obtained from questionnaire to 200 respondents from Bandung spread across the sub-districts. The results revealed that the household solid waste generation was increased by 1.3 to 3.8% compared to the year before the COVID-19 pandemic. The composition of household solid waste was dominated by food and plastic waste, which have increased to 76.43% and 25.81%, respectively. The system dynamics model has predicted the household waste generation from three management scenarios for 30 years of model simulation. Scenario I: the household solid waste was totally managed by a local sanitary agency (existing condition); Scenario II: each household manage their waste by recycling; and Scenario III: the utilization of a local waste bank to manage the waste. The scenario III showed the most effective waste management to reduce the amount of household solid waste generation up to 24% by using waste bank. This scenario can be applied for more prolonged landfill operations up to 17 years.
Anti-corrosion, anti-bacterial and durable atmospheric weatherability of polydimethylsiloxane coating with intrinsic hydrophobicity
Authors: Qiao Mengying , Xu Weichen , Ji Guojun , Zhang Binbin 
Published: April 2022

Abstract
Understanding the corrosion resistance, microorganism suppression and real-world weatherability and application potentiality of intrinsically hydrophobic polydimethylsiloxane (PDMS) coating is of great significance for developing multi-functional composite protective materials. In this paper, a pure PDMS coating was prepared through spray-coating technique on Q235 carbon steel. The surface morphologies, wettability, chemical compositions, corrosion resistance, bacteria adhesion and real-world atmospheric durability behaviors were investigated. The electrochemical assessment results show that the PDMS-coated Q235 carbon steel exhibits greatly enhanced charge transfer resistance (R
ct), positive movement of corrosion potential (E
corr), and extremely low corrosion current density (I
corr). Besides, the PDMS coating presents high anti-bacterial efficiency against Escherichia coli and Pseudomonas sp. adhesion. The real-world atmospheric weatherability, salt spray and abrasion resistance reveal that the PDMS coating can be considered as a superior and durable barrier against marine corrosion and biofouling invasion.
Development of a compact high-density blue core helicon plasma device under 2000 G magnetic field of ring permanent magnets
Authors: LU Zhikang , XU Guosheng , YIP Chi-Shung , CHEN Dehong , WU Xingquan , ZHANG Wei , HU Guanghai , JIN Chenyao , JIANG Di 
Published: April 2022

Abstract
A helicon wave plasma source in a tube of ring permanent magnets (PMs) has been constructed to study the effect of the configuration of the magnetic field with zero magnetic points on plasma parameters. This device also serves as an exploration platform for a simple, compact helicon wave plasma source adaptable to engineering applications. A small-diameter (26 mm) high-density (∼1018 m−3) blue core plasma is produced in ∼1 Pa argon by helicon RF (radio-frequency) discharge using a Nagoya III antenna under magnetic field (∼2 kG) of compact ring PMs (length ∼204 mm). Operational parameters, i.e. RF power and neutral gas pressure are scanned and plasma density is measured by an RF compensated probe to explore the operating characteristics of the device. Iconic feature of a helicon discharge, such as blue core plasmas and E-H-W mode transitions are well observed in the device, despite the wavelength calculated using the conventional dispersion relation of a bounded whistler waves (Chen 1991 Plasma Phys. Control. Fusion
33 339) is order of magnitudes longer than the length of the plasma in this device which seems to suggest that such helicon device is impossible. Surprisingly, the wavelength calculated by the unbounded whistle wave dispersion formula in turn suggests the occurrence of a half wavelength resonance.
Biochemical and molecular characterization of sialylated cervical mucins in sheep
Authors: Abril-Parreño Laura , Morgan Jack , Krogenæs Anette , Druart Xavier , Cormican Paul , Gallagher Mary E , Reid Colm , Meade Kieran , Saldova Radka , Fair Sean 
Published: April 2022

Abstract
Sialic acid occupies terminal positions on O-glycans of cervical mucins, where they contribute to the increased viscosity of mucin thereby regulating sperm transport. This study characterized the sialylated cervical mucins from follicular phase mucus of six European ewe breeds with known differences in pregnancy rates following cervical artificial insemination (AI) using frozen–thawed semen at both synchronized and natural estrus cycles. These were Suffolk (low fertility) and Belclare (medium fertility) in Ireland, Ile de France and Romanov (both with medium fertility) in France, and Norwegian White Sheep (NWS) and Fur (both with high fertility) in Norway. Expression of mucin and sialic acid related genes was quantified using RNA-sequencing in cervical tissue from Suffolk, Belclare, Fur, and NWS only. Cervical tissue was also assessed for the percentage of cervical epithelial populated by mucin secreting goblet cells in the same four ewe breeds. Biochemical analysis showed that there was an effect of ewe breed on sialic acid species, which was represented by Suffolk having higher levels of Neu5,9Ac2 compared with NWS (P &lt; 0.05). Suffolk ewes had a lower percentage of goblet cells than Fur and NWS (P &lt; 0.05). Gene expression analysis identified higher expression of MUC5AC, MUC5B, ST6GAL1, and ST6GAL2 and lower expression of ST3GAL3, ST3GAL4, and SIGLEC10 in Suffolk compared with high fertility ewe breeds (P &lt; 0.05). Our results indicate that specific alterations in sialylated mucin composition may be related to impaired cervical sperm transport.