bluuebunny/crossref_metadata_2025 huggingface dataset:
Formulating diets based on whole cassava tuber (
Authors: Marsetyo  , Sulendre I. W. , Takdir M. , Harper K. J. , Poppi D. P.
Published: March 2021

Context Formulating rations with high energy and protein feeds such as cassava tuber and gliricidia, is an important strategy to increase liveweight gain (LWG) of bulls and improve profitability of smallholder farmers in Indonesia. Aims Two on-farm experiments were conducted to evaluate the effect of increasing the supplementation level of a mixture of cassava (Manihot esculenta) whole root tuber powder and fresh gliricidia (Gliricidia sepium) on feed intake and LWG of Ongole and Bali bulls given fresh corn stover and elephant grass, respectively. Methods Two experiments were conducted, each with five treatments: a basal diet of fresh corn stover (Experiment 1 for Ongole bulls) or elephant grass (Experiment 2 for Bali bulls) fed ad libitum or this diet supplemented with a combination of cassava tuber (whole root tuber including peel, sun-dried and ground) and fresh, chopped gliricidia (1:1) on estimated dry matter (DM) basis, at DM levels of 0.4, 0.8, 1,2 and 1.6% liveweight (LW)/day. Each experiment was run for 18 weeks, consisting of a two week adaptation and 16 week experimental period. Parameters measured included basal DM intake, supplement DM intake, total DM intake, total water intake, faecal pH, daily LWG, feed conversion ratio (FCR) and income over feed cost (IOFC). Key results Increasing supplement level linearly (P < 0.05) decreased basal diet intake, but linearly increased total DM intake and LWG (P < 0.05) in both breeds. Basal diet DM intake was reduced at the rate of 0.43 kg/kg of supplement DM consumed for both Ongole and Bali bulls. Water intake and faecal pH were not affected (P > 0.05) by increasing supplement intake. Inclusion of cassava tuber and gliricidia supplement up to 1.6% LW/day, increased total feed DM intake (up to 3.28 and 3.18% LW/day, for Ongole and Bali bulls, respectively) and LWG (maximum Ongole bulls 0.69 kg/day and Bali bulls 0.46 kg/day). Daily income over feed cost (IOFC) increased significantly (P < 0.05) in association with increased supplement intake in both Experiments 1 and 2. Using the derived model without supplementation, the value of IOFC was only IDR 7802/day and IDR 7687/day, for Experiments 1 and 2, respectively. The highest IOFC was achieved at a supplement intake of 1.6% LW/day with values of IDR 13 949/day and IDR 12 543/day for Experiments 1 and 2 respectively. Conclusions The addition of a cassava tuber and gliricidia mixture up to 1.6% LW/day increased LWG and profit for smallholders fattening bulls. Implications Formulating a ration with cassava tuber and gliricidia can be economically beneficial in cattle fattening systems in Indonesia.
Oligomeric assembly regulating mitochondrial HtrA2 function as examined by methyl-TROSY NMR
Authors: Toyama Yuki , Harkness Robert W. , Lee Tim Y. T. , Maynes Jason T. , Kay Lewis E.
Published: March 2021

Significance

The HtrA2 protease plays a critical role in ensuring proper cellular function and in regulating a variety of different processes, including programmed cell death. Although the three-dimensional structure of a trimeric form of the enzyme has been determined, the mechanism by which this important molecule is regulated remains to be elucidated. Our data reveal that this is accomplished through a second conformation of the enzyme in which it forms a hexamer with much lower affinity for substrate and by the fact that the enzyme remains in a low-activity state until substrate binding leads to domain reorientations, exposing the catalytic center. Together, these two regulatory features help to minimize proteolysis of nonsubstrate proteins that are required for cellular health.
Hepatic Gadd45β promotes hyperglycemia and glucose intolerance through DNA demethylation of PGC-1α
Authors: Wu Ling , Jiao Yang , Li Yao , Jiang Jingjing , Zhao Lin , Li Menghui , Li Bin , Yan Zheng , Chen Xuejin , Li Xiaoying , Lu Yan
Published: March 2021

Although widely used for their potent anti-inflammatory and immunosuppressive properties, the prescription of glucocorticoid analogues (e.g., dexamethasone) has been associated with deleterious glucose metabolism, compromising their long-term therapeutic use. However, the molecular mechanism remains poorly understood. In the present study, through transcriptomic and epigenomic analysis of two mouse models, we identified a growth arrest and DNA damage-inducible β (Gadd45β)–dependent pathway that stimulates hepatic glucose production (HGP). Functional studies showed that overexpression of Gadd45β in vivo or in cultured hepatocytes activates gluconeogenesis and increases HGP. In contrast, liver-specific Gadd45β-knockout mice were resistant to high-fat diet– or steroid-induced hyperglycemia. Of pathophysiological significance, hepatic Gadd45β expression is up-regulated in several mouse models of obesity and diabetic patients. Mechanistically, Gadd45β promotes DNA demethylation of PGC-1α promoter in conjunction with TET1, thereby stimulating PGC-1α expression to promote gluconeogenesis and hyperglycemia. Collectively, these findings unveil an epigenomic signature involving Gadd45β/TET1/DNA demethylation in hepatic glucose metabolism, enabling the identification of pathogenic factors in diabetes.
Targeting mechanosensitive MDM4 promotes lung fibrosis resolution in aged mice
Authors: Qu Jing , Yang Shan-Zhong , Zhu Yi , Guo Ting , Thannickal Victor J. , Zhou Yong
Published: March 2021

Aging is a strong risk factor and an independent prognostic factor for progressive human idiopathic pulmonary fibrosis (IPF). Aged mice develop nonresolving pulmonary fibrosis following lung injury. In this study, we found that mouse double minute 4 homolog (MDM4) is highly expressed in the fibrotic lesions of human IPF and experimental pulmonary fibrosis in aged mice. We identified MDM4 as a matrix stiffness–regulated endogenous inhibitor of p53. Reducing matrix stiffness down-regulates MDM4 expression, resulting in p53 activation in primary lung myofibroblasts isolated from IPF patients. Gain of p53 function activates a gene program that sensitizes lung myofibroblasts to apoptosis and promotes the clearance of apoptotic myofibroblasts by macrophages. Destiffening of the fibrotic lung matrix by targeting nonenzymatic cross-linking or genetic ablation of Mdm4 in lung (myo)fibroblasts activates the Mdm4–p53 pathway and promotes lung fibrosis resolution in aged mice. These findings suggest that mechanosensitive MDM4 is a molecular target with promising therapeutic potential against persistent lung fibrosis associated with aging.
Anastacia Awad: Women in STEM outside the lab
Authors: Houston Stephanie
Published: March 2021

Anastacia Awad is the Head of Diversity and Inclusion (D&I) globally for the Novartis Institutes for BioMedical Research, which is the research engine of Novartis. She completed her PhD in genetics and molecular biology at the University of North Carolina at Chapel Hill, followed by a postdoc with Alan Hall at Memorial Sloan Kettering Cancer Center. I chatted with Anastacia about her career in science and her journey from the bench to industry.
Projective and amplified symmetries in metric–affine theories
Authors: García-Parrado Alfonso , Minguzzi Ettore
Published: March 2021

In this paper we extend the projective symmetry of the full metric–affine Einstein–Hilbert theory to a new symmetry transformation in the space of affine connections called the amplified symmetry. We prove that the Lagrangian of the standard model of particle physics is invariant under this new symmetry. We also show that the gravitational Lagrangian can be modified so that the amplified symmetry extends to the gravitational sector and hence to the whole action. The new theory so constructed is shown to be dynamically equivalent to Einstein–Cartan’s though genuinely metric–affine.
Black holes in the quadratic-order extended vector–tensor theories
Authors: Minamitsuji Masato
Published: March 2021

We investigate the static and spherically black hole solutions in the quadratic-order extended vector–tensor theories without suffering from the Ostrogradsky instabilities, which include the quartic-order (beyond-)generalized Proca theories as the subclass. We start from the most general action of the vector–tensor theories constructed with up to the quadratic-order terms of the first-order covariant derivatives of the vector field, and derive the Euler–Lagrange equations for the metric and vector field variables in the static and spherically symmetric backgrounds. We then substitute the spacetime metric functions of the Schwarzschild, Schwarzschild–de Sitter/anti-de Sitter, Reissner–Nordström-type, and Reissner–Nordström–de Sitter/anti-de Sitter-type solutions and the vector field with the constant spacetime norm into the Euler–Lagrange equations, and obtain the conditions for the existence of these black hole solutions. These solutions are classified into the two cases 1) the solutions with the vanishing vector field strength; the stealth Schwarzschild and the Schwarzschild–de Sitter/anti-de Sitter solutions, and 2) those with the nonvanishing vector field strength; the charged stealth Schwarzschild and the charged Schwarzschild–de Sitter/anti-de Sitter solutions, in the case that the tuning relation among the coupling functions is satisfied. In the latter case, if this tuning relation is violated, the solution becomes the Reissner–Nordström-type solution. We show that the conditions for the existence of these solutions are compatible with the degeneracy conditions for the class-A theories, and recover the black hole solutions in the generalized Proca theories as the particular cases.
Deriving and validating an electrodynamic model of a voltage transformer from scratch
Authors: El Hage Fabio S , Vieira Fabio P B , Carareto Rodrigo
Published: March 2021

Comprehending the in-depth functioning of a voltage transformer beyond the trivial voltage ratio, generally deducted from the application of Faraday’s law to an open secondary circuit, can be quite challenging for both students and teachers. In this paper, the authors propose an approach that uses Faraday’s and Ohm’s laws alone to derive an electric equivalent circuit for a transformer, with which is possible to accurately explain and predict currents and voltages in its primary and secondary coils under different load resistors connected to the secondary. The authors intend to use a common real-world application as motivation for students to learn Faraday’s law in the context of a modelling and simulation framework, which consists of deriving a model from fundamental physical laws that, after experimental validation, is capable of accurately predicting and explaining a complex phenomenon.
Impact of stoichiometry and strain on Ge1−x
Sn
x
alloys from first principles calculations
Authors: O’Donnell Conor , Sanchez-Soares Alfonso , Broderick Christopher A , Greer James C
Published: March 2021

We calculate the electronic structure of germanium-tin (Ge1−x
Sn
x
) binary alloys for

0
⩽
x
⩽
1

using density functional theory (DFT). Relaxed alloys with semiconducting or semimetallic behaviour as a function of Sn composition x are identified, and the impact of epitaxial strain is investigated by constraining supercell lattice constants perpendicular to the [001] growth direction to the lattice constants of Ge, zinc telluride, or cadmium telluride substrates. It is found that application of 1% tensile strain reduces the Sn composition required to bring the (positive) direct band gap to zero by approximately 5% compared to a relaxed Ge1−x
Sn
x
alloy having the same gap at Γ. On the other hand, compressive strain has comparatively less impact on the alloy band gap at Γ. Using DFT calculated alloy lattice and elastic constants, the critical thickness for Ge1−x
Sn
x
thin films as a function of x and substrate lattice constant is estimated, and validated against supercell DFT calculations and experiment. The analysis correctly predicts the Sn composition range at which it becomes energetically favourable for Ge1−x
Sn
x
/Ge to become amorphous. The influence of stoichiometry and strain is examined in relation to reducing the magnitude of the inverted (‘negative’)

Γ

7

−

–

Γ

8

+

band gap, which is characteristic of semimetallic alloy electronic structure. Based on our findings, strategies for engineering the semimetal-to-semiconductor transition via strain and quantum confinement in Ge1−x
Sn
x
nanostructures are proposed.
Acoustic wave surfing: spin waves and spin pumping driven by elastic wave
Authors: Froes D , Arana M , Sampaio L C , Sinnecker J P
Published: March 2021

In magnon spintronics it is fundamental that magnons can propagate over large distances to allow spin flux or information to be processed. Through micromagnetic simulations we investigate the spin-wave propagation driven by acoustic excitation in narrow Ni stripes, varying the level of coupling between spin and acoustic waves. We consider different cases depending on the extension of the acoustic wave propagation, which is generated on the left end of the stripe. When acoustic waves are confined at the origin, the spin waves are free to propagate but vanish after the decay length, which is dependent on the dissipation. On the other hand, when the acoustic waves are present in the whole stripe, spin and acoustic waves propagate together with the spin wave maintaining a constant amplitude. Images of the spin-wave propagation modes and the dispersion relations are discussed for different acoustic wave attenuation lengths. Motivated by recent experiments, we consider a Pt line over and crossing the Ni stripe and calculate the spin and charge current maps at the Ni/Pt interface and the Pt line, respectively, and the AC and DC components of the inverse spin Hall effect voltage.
Realizing stable half-metallicity in zigzag silicene nanoribbons with edge dihydrogenation and chemical doping
Authors: Song Lingling , Yang Zhihong , Liu Lu , Yuan Liwei , Zhao Han , Chen Xing , Zhang Yan , Zheng Xiaohong
Published: March 2021

Although many schemes have been proposed to obtain full half-metallicity in zigzag silicene nanoribbons with edge monohydrogenation (H–H ZSiNRs) by chemical modification, the resulted negligible energy difference between the antiferromagnetic (AFM) and ferromagnetic (FM) configurations makes the half-metallicity hardly observable practically. In this work, based on density functional calculations, we find that the ZSiNRs with edge dihydrogenation (H2–H2 ZSiNRs) can be tuned to be half-metallic by replacing the central two zigzag Si chains with two zigzag Al–P chains, and more importantly, the FM–AFM energy difference is significantly increased compared with the H–H cases. The obtained half-metallicity originates from the different potential between two edges of the ribbon after doping, which results in the edge states of two spin channels shifting oppositely in energy. This mechanism is so robust that the half-metallicity can always be achieved, irrespective of the ribbon width. Our finding provides a fantastic way for achieving stable half-metallicity in ZSiNRs.
Calibration and uncertainty analysis of a combined tracking-based vision measurement system using Monte Carlo simulation
Authors: Jiang Tao , Cui Haihua , Cheng Xiaosheng , Du Kunpeng
Published: March 2021

A global stereovision system combined with a local vision sensor is an effective approach to large-scale object measurement. However, obtaining the error distribution of such an approach remains a key research challenge in vision metrological applications. This paper investigates the calibration and the reconstruction uncertainty estimation method of the combined vision system. The measurement principle and the calibration method of the transformation matrix between the tracking-based measurement coordinate systems are presented. Furthermore, Monte Carlo simulation is utilized to determine the reconstruction uncertainty based on the theoretical measurement model and the experiment-based input uncertainty. The overall measurement uncertainty of the combined system is found to be 34.5% higher than that of the global vision system, which is more sensitive to the input pixel uncertainty than the local vision system. However, the combined vision system can achieve comparable measurement results within its larger working volume. This work contributes to a better understanding of the measurement uncertainty in combined tracking-based vision systems, as well as providing a few useful practice guidelines for using such a visual system.
Thermal radiation elimination method for high-temperature digital image correlation using polarization camera
Authors: Wang Huanqing , Zhang Qian , Ge Pengxiang , Zhu Yilei , Wang Yonghong
Published: March 2021

Digital image correlation (DIC) is a material displacement and strain measurement technology based on visible light illumination. At high temperatures, the problem of thermal radiation seriously affects the quality of acquired images and restricts the development of high-temperature DIC technology which is increasingly applied in the field of high-temperature measurement due to stringent measurement temperature requirements. A thermal radiation elimination method based on the use of a polarization camera for high-temperature DIC measurements is proposed in this study. This method uses a polarization camera combined with a filter set to achieve clear image acquisition at 1200 °C and effectively eliminates the effects of thermal radiation on image acquisition. The gray average method and an image inverse filtering algorithm are adopted in this study to eliminate high-temperature thermal disturbances. Finally, a high-temperature DIC measurement system is independently designed, and a rigid-body displacement experiment is carried out on an FV566 steel specimen to obtain time–displacement curves. A set of uniaxial tensile tests is also performed on FV566 steel material to explore its strain field at 1200 °C.
Implication of polymeric template agent on the formation process of hybrid halide perovskite films
Authors: Giuri Antonella , Munir Rahim , Listorti Andrea , Esposito Corcione Carola , Gigli Giuseppe , Rizzo Aurora , Amassian Aram , Colella Silvia
Published: March 2021

The use of polymeric additives supporting the growth of hybrid halide perovskites has proven to be a successful approach aiming at high quality active layers targeting optoelectronic exploitation. A detailed description of the complex process involving the self-assembly of the precursors into the perovskite crystallites in presence of the polymer is, however, still missing. Here we take starch:CH3NH3PbI3 (MAPbI3) as example of highly performing composite, both in solar cells and light emitting diodes, and study the film formation process through differential scanning calorimetry and in situ time-resolved grazing incidence wide-angle x-ray scattering, performed during spin coating. These measurements reveal that starch beneficially influences the nucleation and growth of the perovskite precursor phase, leading to improved structural properties of the resulting film which turns into higher stability towards environmental conditions.
Enhanced acetone sensing properties based on in situ growth SnO2 nanotube arrays
Authors: Cheng Pengfei , Wang Chen , Wang Yinglin , Xu Luping , Dang Fan , Lv Li , Li Xu
Published: March 2021

Large-scale and well-aligned in situ growth SnO2 nanotube (NT) arrays have been synthesized directly on the surface of the Al2O3 ceramic tube by a cost-effective template self-etching method. The morphology of in situ SnO2 NTs can be adjusted by changing the concentration of urea. The structure and morphology characteristics of SnO2 NT were examined via x-ray diffraction, BET, and scanning electron microscopy, respectively. A series of detections were carried out to evaluate the gas sensing performances. The results indicated that in situ growth SnO2 NT arrays sensor exhibited an excellent response (S = 20.3), good linearity under the concentration range of ppm level (5–300 ppm), and outstanding selectivity to 100 ppm of acetone gas. Compared with the sensors fabricated by a slurry-coating method, the controllable in situ assembled SnO2 NT arrays exhibited a more stable structure and easier fabrication process. The high acetone sensing performance might due to the unique hollow structure and favorable orientation growth. The dominant sensing mechanism about the in situ growth SnO2 NT arrays sensor has been discussed in detail. It is expected that in situ growth SnO2 NT arrays sensor with the general working principle and controllable growth strategy will become a promising functional material in monitoring and detecting acetone.
Study on preparation, stability, thermal conductivity, and viscosity of silver nanoparticles-decorated three-dimensional graphene-like porous carbon hybrid nanofluids
Authors: Jin Can , Wu Qibai , Zhang Haiyan , Yang Guoqiang , Yuan Xingxing , Fu Huiqing
Published: March 2021

In the present study, a novel silver nanoparticles-decorated three-dimensional graphene-like porous carbon (Ag/3D GPC) nanocomposite has been synthesized via the method of carbonization and reduction of silver ions at the same time. This Ag/3D GPC nanocomposite possess an interconnected network of well crystalized and submicron-sized macropores with thin graphene walls of several nanometers, where silver nanoparticles distributing uniformly. The water based and ethylene glycol based Ag/3D GPC hybrid nanofluids have been prepared without any surfactant. The hybrid nanofluids with low concentration (<0.8 wt%) can be steadily dispersed for more than six months. The thermal conductivity enhancement for the nanofluids with 0.1 wt% can reach 10.3% and 8.8% at 25 °C compared with pure water and ethylene glycol, respectively. The viscosity of nanofluids is investigated, the temperature dependence of the dynamic viscosity obeys an Arrhenius-like behavior. The prepared Ag/3D GPC hybrid nanofluids with good stability and thermal conductivity are promisingly considered to be used in heat transfer field.
Hybrid liquid-metal heat dissipation structure enabled by phase transition for flexible electronics
Authors: Li Haicheng , Zhang Huilong , Min Seunghwan , Zhou Tao , Gong Shaoqin , Feng Xue , Ma Zhenqiang
Published: March 2021

Flexible electronics incorporating built-in thin-film semiconductors with soft substrates allow devices or systems to conform to desired shapes, creating opportunities for various novel applications. High radio-frequency (RF) power flexible devices play significant roles in flexible wireless communication and other miniaturized microwave systems in the future. However, high power operations of devices generate a massive amount of heat, and if not dissipated effectively, the excessive heat can degrade the performance of flexible active devices and even cause irreversible damage to the systems. In this work, we present a hybrid heat dissipation structure that can be used in flexible electronics where significant heat dissipation is needed. The structure was designed with finite element method-based simulations with the goal of achieving both high heat dissipation efficiency and mechanical flexibility. The structure was fabricated using a phase transition technique, greatly simplifying the fabrication process without need of handling liquid in the fabrication process, and was tested on an ultra-thin flexible AlGaN/GaN high electron mobility transistor (HEMT). The maximum power handled by the heat-managed HEMT measured from the I
DS–V
DS curve was 2.33 times larger than a reference HEMT without the heat dissipation structure. This demonstration opens new prospects for expanding the applications of flexible electronics toward high-power radio frequency regime in the future.
Landau kinetic equation for dry aligning active models
Authors: Patelli Aurelio
Published: March 2021

The Landau equation is a kinetic equation based on the weak coupling approximation of the interaction between the particles. In the framework of dry active matter this new kinetic equation relies on the weak coupling approximation of both the alignment strength and the magnitude of the angular noise, instead of the hypothesis of diluteness. Therefore, it is a kinetic equation bridging between the Boltzmann (Bertin et al 2006 Phys. Rev. E 74 022101), and the Smoluchowski (Baskaran et al 2010 J. Stat. Mech. P04019) approximations, and allowing analytical descriptions at moderate densities. The form of the equation presents non-linear and density dependent diffusions and advections fully derived by the microscopic equations of motions. Finally, implementing the BGL procedure (Peshkov et al 2014 Eur. Phys. J. Spec. Top.
223 1315–44), the parameters of the Toner–Tu equations are derived showing the appearance of linearly stable homogeneous ordered solutions and mimicking the results obtained from the Boltzmann approach.
Review on vibration isolation technology
Authors: Feng Xiong , Yan Li , Chun Wangying
Published: March 2021

Submarine acoustic stealth technology is very important for national defense constructions. vibration isolation technology is the key technology to realize submarine acoustic stealth. In this paper, the development of vibration isolation technologies in recent years is reviewed. The characteristics of several important active and passive vibration isolation technologies and vibration isolators are analyzed in detail. Besides, the latest research directions are discussed. Afterwards, the deficiencies of current intelligent vibration isolation technology and personal views on the development of intelligent vibration isolation technology are presented.
The Design of High Precision Arbitrary Waveform Generator Based on DDS Technology and FPGA
Authors: Ren Li-Min , Xue Xiao , Zheng Yang-Bing
Published: March 2021

Combining with the IP core advantage of FPGA, a signal generator which can generate arbitrary waveform is designed on the basis of direct digital synthesis technology in this paper. The INTEL company’s Cyclone IV series EP4CE6F17C8N is used as the control core and the front-end interface design is carried out by XMAL. The software control operation of the logical processing interface is realized through C#. The signal generator has the characteristics of single cycle waveform with 256 sampling points, clear spectrum analysis, higher purity and high precision. The arbitrary waveform displayed on oscilloscope is wonderful after filtering out high frequency signal by seven order butter worth filter.
Research on Weak Signal Line Spectrum Enhancement Algorithm Based on Correlation Detection
Authors: Huang Chengshun , Zhao Chenglin
Published: March 2021

The correlation detection and adaptive line spectrum enhancement(ALE) algorithm in weak signal detection is presented. Aiming at the problem that the traditional ALE has no obvious effect of line spectrum enhancement at low signal-to-noise ratio(SNR), we propose a modified ALE algorithm based on coherent integrator. Combining this ALE and sliding window correlation, the effect of ALE is clearly improved. The simulation results show that the weak signal receiving ability can be improved by 8 dB under the same line spectrum condition.
Design of a management system of packaged FBG sensor based on RFID for wind turbine blade
Authors: Lin Zhe-Cong , Liu Shuo-Chao , Lu Meng , Zhu Ping-Yu
Published: March 2021

With the application of fiber bragg grating (FBG) sensors in the condition monitoring of wind turbine blades, the layout management of FBG sensors with different central wavelengths and manufacturing processes has attracted much attention. A management system of FBG sensor based on RFID technology is proposed. The management system includes three parts: packaging process of FBG sensor with RFID chip, RFID chip stored information and the FBG sensors status monitoring system, the FBG sensor installation on full scale field wind turbine blade and its maintenance. The proposed management system introduces RFID technology into the blade monitoring using FBG sensor. It provides effective digital management method for the manufacturing, the layout, the installation and the maintenance process of the FBG sensor on the wind turbine blade.
Lightweight Design Of Composite Spinner For Large Wind Turbine
Authors: Liu Zongwei , Wu Wensong , Du Jing , Wang Shuang
Published: March 2021

Taking a 5MW wind turbine spinner as the research object and the lightest quality of the structure as target under the condition of ensuring that the comprehensive performance of the structure meets the design requirements, using the combining method of finite element analysis and multidisciplinary structural optimization, applying hierarchical optimization strategy, the optimal mathematical model were established. The lightweight design scheme of spinner was obtained by optimizing the layout of the stiffener and the laminate parameter. The structure analysis results indicate that the optimized spinner model meets the requirements in terms of comprehensive performance, while the quality is greatly reduced. This provides a method for the lightweight design of the spinner and also provides an idea for the optimization design of large composite shell structure composed of multiple parts.
Obstacle recognition of indoor blind guide robot based on improved D-S evidence theory
Authors: Du Dongqing , Xu Jinyong , Wang Yan
Published: March 2021

The ability to recognize obstacles with high accuracy is an important guarantee for the safe driving of indoor blind guide robots. In order to improve the accuracy of the indoor blind guide robot’s recognition of obstacles, a sensor data fusion method based on D-S evidence theory of the genetic algorithm is proposed. The system uses ultrasonic sensors, infrared sensors, and lidar to collect environmental information. Under the premise of determining the weight range of various sensors, the genetic algorithm is used to optimize each weight and the optimized weight is substituted into D-S evidence theory for data fusion. In application, the determination of the weight of evidence is the key to weighting and fusion of evidence. Through the comparison of the two fusion results, under the same conditions, the method proposed in this paper has an accuracy of 0.94 for the obstacle recognition of the indoor guide robot, which is 33.0% higher than the result of unweighted fusion. The algorithm can also be used for obstacle detection in other systems.
Design of Automobile Engine Fault Diagnosis Instrument Based on STM32 and LabVIEW
Authors: Huang Shuang Cheng , Wei Xinhua
Published: March 2021

The designer designed an engine fault diagnosis instrument with STM32 single chip microcomputer combined with LabVIEW technology for automobile engine failure. The system will use the eddy current sensor to collect the engine vibration signal and send it to the host computer program written by LabVIEW for high-order spectrum analysis. In this way, the working status of the engine can be obtained in real time. Experimental results show that the designed diagnostic instrument is highly efficient and highly reliable. It can meet the real-time diagnosis requirements of engine status.
Research on straightness detection of steel strip edge based on machine vision
Authors: Li Shuiping , Luo Chen Cheng
Published: March 2021

In order to accurately detect the straightness of steel strip edge, a method of minimum containment area evaluation of straightness based on visual measurement scanning discriminant search is proposed. Firstly, opencv is used to preprocess the collected steel strip image, then Canny edge extraction operator is used to extract the steel strip edge, and the steel strip image contour is extracted. Finally, the straightness evaluation method proposed in this paper is used to measure the steel strip straightness. Compared with the measurement results of the two end point connection method and the least square method, the measurement results of the proposed straightness evaluation method are closer to the manual test results, which is conducive to improving the accuracy of steel strip straightness detection.
Research Progress of Exoskeleton for Hand Rehabilitation following stroke
Authors: Li Yu , Gao Xingyu , Liao Bin , Peng Yanhua , Chen Yu Jing
Published: March 2021

Based on the hand rehabilitation exoskeleton, the research results of three driving modes in recent years, namely cable, connecting rod and pneumatic system, were classified, summarized and analyzed. Through research and analysis, the results of structural dimensions, structural degrees of freedom, drive selection scheme, control strategy and sensor selection scheme which are more suitable for human hand rehabilitation exoskeleton are obtained, which can provide reference for exoskeleton researchers.
Research on Coherent Light detection Method Based on Phase Control of Fiber Delay Line
Authors: Zhang Junyu , Jing Xiao , Li Zhiwen , Huang Qingchun
Published: March 2021

With the system modeling and simulation, analyzed the mechanisms of signal transmission and storage, and phase-controlling, and researched the relationship between time-delay and phase-delay. The effect of optical path difference on optical phase-matching is investigated in time domain and frequency domain. The results shows that, the signal power will obtain maximum after coherent mixing when the phase between signal light and reference light is 2nπ(n=0, 1, 2……); the signal power will obtain minimum when it is (2n+1)π(n=0, 1, 2……), and the mixing signal of other phase relationship will vary in this range. And it is proved that the time delay of optical fiber delay line could effectively compensate the phase delay which generated in the transmission and a phase controlling of the signal transmission could be achieved.
Research on on-line ultrasonic testing of small diameter thin wall stainless steel straight welded pipe
Authors: Hou Huaishu , Lu Ding , Zhang Shiwei , Zhang Yi , Cheng Chaolei
Published: March 2021

In the production process of thin-walled stainless steel longitudinal welded pipe, there are many defects, such as cracks, porosity, partial welding, incomplete penetration, incomplete fusion. In this study, a local coupling water tank and six ultrasonic linear focusing probes with a center frequency of 5MHz were used to realize the defect identification of the straight welded pipe in the twisted state through the combined detection of the ultrasonic shear wave, longitudinal wave and creeping wave, which can meet the on-line inspection requirements of small-diameter thin-walled stainless steel straight welded pipe.
Optimization of Tool Path for Surface Machining Based on Accuracy
Authors: He Fang , Tian Meizi , Luo Jihui , He Renqi
Published: March 2021

Surface machining is the key technology in numerical control (NC) machining, and the planning of tool path is the basis and key of NC programming. Based on the improvement of the precision and efficiency of surface machining, this work analyzes the approximation machining error of NC machining of multi-coordinate surface. The tool step and calculation of cutting distance for tool path are discussed. The principle of tool path planning during surface NC machining programming is proposed, and the track verification is carried out with examples.
Fault diagnosis method of rare earth extraction production line based on wavelet packet and alexnet transfer learning
Authors: Li An-Hao , Luo Yi , He Yu-Hua , Cheng Zhe , Wang Teng-Fei , Peng Yan-Hua
Published: March 2021

In rare earth production, improving the fault detection of extraction equipment has a key impact on improving extraction efficiency and product quality. The traditional method is based on the observation of the liquid level, the efficiency and accuracy can’t be guaranteed. In this paper, a fault diagnosis and recognition method for rare earth extraction production line based on wavelet packet and alexnet transfer learning is proposed. Taking six fault states of rare earth extraction production line as the research object, the fault signal is extracted by wavelet packet decomposition, and the corresponding target data set of time-frequency diagram is generated. Then, the pre trained alexnet model is trained and fine tuned on the generated target data set, and finally applied to fault diagnosis of rare earth extraction production line. The results show that the proposed method is more accurate than the traditional convolution neural network, which verifies the effectiveness of the method.
On Sequential-Pattern-Based Intelligent Compilation of Aircraft Assembly Process
Authors: Ouyang Sen-Shan , Song Liang , Liu Xiang-Feng , Chen Chen , Chen Zhen-Yu
Published: March 2021

The aviation industry which aircraft manufacturing dominates is an important sector to measure a nation’s air power. The application of new technologies to optimize the process, increase the speed and upgrade the quality of airplane assembly, a crucial link in its manufacturing, is an effective method to improve the capacity. The combination of traditional processes and emerging technologies greatly improves its efficiency, reduces its labor costs and promotes the innovation and upgrade of traditional technologies. For aircraft manufacturers, the Assembly Outline (AO) refers to an essential document used for the guidance of the assembly process. Low efficiency and under-structuration of compilation, which is also difficult to upgrade, put a limit on the application of information and digitization technologies and has an impact on the overall airplane production cycle, due to present manual work in quantity and imbalance of informationization. Via sequential-pattern-based data mining introduced in this paper, patterns of AO processes are dug up to form a set based on which it is possible to quickly make a recommendation of the optimal process for the compiler, effectively reducing the duration of compilation and modification and improving the efficiency.
Research on Dynamic Performance Simulation of In-wheel Motor Electric Vehicle Based on CarSim-Simulink
Authors: Liu Qiusheng , Xie Dacheng , Hu Shenglong , Wu Jinhua
Published: March 2021

In order to reduce test costs and improve work efficiency, on the basis of the existing in-wheel-motor electric vehicle platform, CarSim software is used to establish a complete in-wheel-motor electric vehicle model that matches the actual vehicle. Based on Simulink, the dynamic model of the in-wheel motor is established. By defining the interface between the vehicle and the motor drive system, a joint simulation platform for in-wheel motor electric vehicles is established based on CarSim-Simulink, and simulation verification is performed on it. The results show that the established simulation model has high accuracy, can better simulate the existing experimental vehicle, accurately reflect the dynamic performance response of the vehicle, and provide a basis for further research and verification of control algorithms.
An improved genetic algorithm for low carbon dynamic scheduling in a discrete manufacturing workshop
Authors: Li Nie , Wang Xiaogang , Bai Yuewei
Published: March 2021

Due to energy consumption activities, manufacturing enterprises produce many carbon dioxide emissions in the production process, which exacerbates global climate deterioration. The production scheduling optimization method is an effective way to reduce carbon emissions and relieve environmental pressure. The paper proposed a low-carbon dynamic scheduling optimization method to solve machine failure interference and to minimize the total cost of production and carbon emissions in the discrete manufacturing workshop. The rolling window mechanism driven by abnormal events and rescheduling strategy are used to update the original schedule in real-time when the machine fails. In the carbon emission measurement method, the machine’s carbon emission parameters in different states are considered. The traditional genetic algorithm is improved in the initial population strategy and crossover operator. The experimental results show that the proposed low-carbon dynamic scheduling method based on the improved genetic algorithm can effectively reduce carbon emissions under the premise of ensuring the completion of production tasks as soon as possible.
Failure criticality evaluation of ship propeller shaft system based on Fuzzy FMECA method
Authors: Wang Ruixin , Chen Zhimin , Zhou Taotao , Xia Yuan
Published: March 2021

The propeller shaft system is the key system for power transmission on board. The components of the system are complex, the working environment is bad, the failure modes are numerous, and the failure consequences are serious. FMECA (Failure Modes, Effects and Criticality Analysis) is difficult to accurately and quantitatively carry out criticality assessment. Therefore, in view of the complex navigation environment, the fuzzy FMECA method is used to evaluate the failure mode criticality of propeller shaft system. On the basis of FMECA, the factor set with maintainability and testability is established, and the factor level set, fuzzy evaluation matrix and factor weight set are determined, and the consistency judgment is made. Finally, the fuzzy comprehensive evaluation is carried out to obtain the accurate and quantifiable failure mode criticality ranking. Compared with the traditional FMECA method, fuzzy FMECA can consider the limited maintenance conditions and test conditions on board, accurately quantify the criticality degree, and take into account more expert opinions, so as to improve the authenticity, accuracy and repeatability of criticality assessment. Therefore, the fuzzy FMECA method can better evaluate the criticality degree of propeller shaft system, and the results can effectively guide the improvement of propeller shaft design and maintenance work.
Application of laser tracker in the industrial measurement field
Authors: Hu Chang’an , Luo Shutong , Li Wanze , Cai Dongyan , Li Jiangang
Published: March 2021

In recent years, with the rapid development of modern three-dimensional space technology, laser tracker has become a mature technology, high efficiency, stable and reliable performance of high-precision large-size measurement instruments in the industrial measurement system. In some major industries, the 3d high-precision measurement method represented by laser tracker has gradually replaced the traditional measurement method and is widely used in the installation and detection of large precision equipment. This paper mainly introduces the structure, working principle, advantage, and laser tracker applications in main industries.
Temperature Variation of Steel Plate with Different Thickness on Normalizing Process
Authors: Yanchun Lv , Zhang Yuefei , Bao Wanghai , Wang Weihua , Liu Yang
Published: March 2021

By placing the thermocouples inside the steel plate and measuring the actual temperature in the normalizing process, combined with the numerical calculation, the temperature variation law of different thickness steel plate is simulated and calculated. The calculation shows that the core cooling rate is the lowest at the beginning of cooling. With the decrease of temperature, the cooling rate changes and then continues to decrease. The maximum cooling rate is 0.53°C/s-0.35°C/s. When the plate surface temperature reaches 642°C-673°C, the cooling rate of steel plate surface is consistent with that of core.
Steady State Unbalance Response Analysis of Internal Combustion Engine Crankshaft Based on Torsional Vibration
Authors: Lin Wang , Chen Ni , Zhang YuBai
Published: March 2021

Crankshaft is one of the main moving parts in internal combustion engine. The instantaneous gas pressure and effective crank radius of each cylinder of the engine and the ignition interval angle of each cylinder make the torque of each crank change constantly, which causes the torsional vibration of the crankshaft. Based on the lumped parameter model, the transfer matrix method is used to analyze the steady-state unbalance response of internal combustion engine crankshaft, which has a certain reference value for mastering the influence of torsional vibration on the working state and strength safety of crankshaft.
Analysis and Research on Multi-layer Docking Error of Complex Interlayer Column Module Based on Point Cloud
Authors: Han Jiang , Zhang Qing , Zhang Zifeng
Published: March 2021

Modular design of large offshore oil and gas module reduces the construction difficulty of the whole building, but increases the cumulative error between modules. For large-scale steel structure buildings, the error between the inter-story column modules will affect the overall building stability. It is a feasible method to use point cloud to monitor the errors in real time, so as to trim the columns in time. The goal of this paper is to put forward a set of error analysis method which is suitable for point cloud pre-matching of interlayer integral column. This method includes the calculation and analysis of the center line angle error of each butt joint and the position error of butt joint center of gravity after transformation based on interlayer optimal matching. In practical work, the column structure with large error can be trimmed according to the calculated data.
Research on Intelligent recognition system of Cotton apical Bud based on Deep Learning
Authors: Li Jianliang , Zhi Xinlei , Wang Yingying , Cao Qingzheng
Published: March 2021

Cotton topping is a key link in the whole cotton production process, which can eliminate the top growth advantage and promote cotton production and income. The automation of cotton topping can greatly reduce the topping time and labor intensity, and the high-speed and accurate identification of cotton top buds is the prerequisite and basis for automatic topping. This article designs a cotton top bud intelligent identification system based on YOLOv3 network, which can detect cotton top buds in visible light images in real time, and provide visual information for the subsequent realization of cotton top bud position measurement and mechanical control. A computer workstation (RTX2070s) was used to identify 15049 cotton top bud images under different weather and illumination conditions. The results show that the average time of single frame image recognition is controlled within 100 milliseconds, and the top bud recognition rate reaches 96%, which creates good conditions for the development of automatic cotton topping equipment and has broad application prospects.
A review of key tools for oil pipe blockage operation in gas wells under pressure
Authors: Song Chunyuan , Hu Shoulin , He Yunbin , Yang Hai
Published: March 2021

Blockage in tubing is an important guarantee for gas wells under pressure. The internal blockage is to close the channel inside the tubing through a sealing device, the pipe string can be lifted and lowered under pressure. In order to prevent natural gas from leaking through the tubing channel during well completion and string lifting operations, a plugging tool in the tubing is required to block the tubing channel, and the blockage is removed after the operation is completed to effectively control the pressure in the well. This article starts with the key tools related to internal plugging operations in Snubbing operation, introduces the basic principles of setting the internal plugging barriers when running the tubing string in completion operations, and introduces the key tools for internal plugging when the tubing runs in completion operations. The internal plugging method of the pipe string under pressure is introduced. The key tools (bridge plugs) and setting methods that have been matured or formed at home and abroad when the pipe string is lifted in workover are introduced. Well technology and key tool selection provide reference. Finally, we analyze and think about the domestically developed self-developed internal plugging tools for pressurized operations in my country. It is believed that internal clogging is not an isolated process of oil, gas, and water plugging, but is usually a process of multi-system construction processes working together. The key domestic tools and equipment also need to further improve their autonomous capabilities in terms of overall performance and stability, as well as intelligence.