bluuebunny/crossref_metadata_2025 huggingface dataset:
Discarded gems: Thermoelectric performance of materials with band gap emerging at the hybrid-functional level
Authors: Berland Kristian , Løvvik Ole Martin , Tranås Rasmus
Published: August 2021

A finite electronic band gap is a standard filter in high-throughput screening of materials using density functional theory (DFT). However, because of the systematic underestimation of band gaps in standard DFT approximations, a number of compounds may be incorrectly predicted metallic. In a more accurate treatment, such materials may instead appear as low band gap materials and could have good thermoelectric properties if suitable doping is feasible. To explore this possibility, we performed hybrid functional calculations on 1093 cubic materials listed in the Materials Project database with four atoms in the primitive unit cell, spin-neutral ground state, and a formation energy within 0.3 eV of the convex hull. Out of these materials, we identified eight compounds for which a finite band gap emerges. Evaluating electronic and thermal transport properties of these compounds, we found the compositions MgSc2Hg and Li2CaSi to exhibit promising thermoelectric properties. These findings underline the potential of reassessing band gaps and band structures of compounds to identify additional potential thermoelectric materials.
Improved photodetection performance enabled by gradient alloyed quantum dots
Authors: Dan Zhiying , Wang Chuanglei , Gao Wei , Shu Kaixiang , Wu Liangwei , Wang Weizhe , Zhao Qixiao , Liu Xiaojing , Liu Xiao , Huo Nengjie , Li Jingbo
Published: August 2021

Hybrids composed of two-dimensional (2D) and zero-dimensional (0D) materials have demonstrated great application potentials in electronics and optoelectronics. The CdSe@Zn1−XCdXS (CSZCS) quantum dots (QDs) possess unique gradient band structure with a continuously increasing energy level along the radial direction from the center to the surface, which is favorable for light-harvesting, photocarrier transfer and promising for photovoltaic and photodetection applications. Here, the gradient alloyed CSZCS QDs, acting as a photosensitive layer, have been first integrated with 2D InSe as a carrier transport layer. The new 2D–0D hybrids exhibit a 300-fold improvement in responsivity compared with that of pristine InSe, which is much more superior to hybrids composed of core–shell CdSe@ZnS QDs/InSe. Thanks to the low dark current and large photo-gain induced by the photo-gating effect, the responsivity and detectivity of the CSZCS QDs/InSe photodetector can reach up to 30.16 A/W and 1.69 × 1012 Jones, respectively. This work provides a new kind of promising QDs with the gradient alloyed structure that can be explored into 2D–0D hybrids for further development of high-performance photodetectors.
Role of contrast of a relativistic femtosecond laser pulse interacting with solid and structured targets
Authors: Ivanov K.A. , Shulyapov S.A. , Gorlova D.A. , Mordvintsev I.M. , Tsymbalov I.N. , Savel’ev A.B.
Published: August 2021

We consider the effect of a pre-plasma layer inevitably present in experiments on the acceleration of electrons and ions during interaction of a relativistic femtosecond laser pulse with a dense plasma. The interaction regimes are identified in which the presence of such a layer can significantly increase the average and maximum energies of electrons. The regimes are discussed in which an artificial nanosecond prepulse makes it possible to produce a collimated electron beam with a high charge and an average energy of up to 10 ponderomotive energies in the direction of the reflected or incident laser beam. It is shown that the acceleration of ions, as a rule, requires an ultrahigh contrast of the laser pulse, since the parameters of the accelerated ion beams deteriorate significantly in the presence of preplasma or due to the evaporation of a thin-film target. The regimes of interaction of laser pulses with thick targets, in which heavy multiply charged ions can be accelerated by cleaning the surface with a prepulse, are also discussed. An essential part of the review is devoted to the interaction of radiation with micro- and nanostructured targets. Both the methods of their fabrication and the issues related to the interaction of a femtosecond laser pulse and its contrast with such structures are considered.
Using machine-learning methods for analysing the results of numerical simulation of laser-plasma acceleration of electrons
Authors: Volkova T.M. , Nerush E.N. , Kostyukov I.Yu.
Published: August 2021

Using machine-learning methods based on self-organising Kohonen maps, the results of numerical simulation of the acceleration of electrons during the interaction of high-power laser radiation with plasma are analysed and classified. The particle-in-cell (PIC) method is used to simulate the interaction in a wide range of parameters (laser intensity and plasma concentration). For each set of parameters, the spectrum of accelerated electrons is found, based on which the charge, average energy, and relative energy spread of accelerated electrons are calculated. Using the obtained values as input parameters of the map, the classification of various acceleration regimes is performed. The developed scheme can be used to identify the optimal acceleration regimes under more realistic conditions, considering a larger number of parameters.
Acceleration of electrons in hollow glass capillaries under the action of intense picosecond laser pulses
Authors: Flegentov V.A. , Safronov K.V. , Gavrilov D.S. , Kakshin A.G. , Pkhaiko N.A. , Potapov A.V.
Published: August 2021

The generation of relativistic electron beams in hollow glass capillaries is investigated using a picosecond laser system. A plasma is formed in a capillary due to the ablation of its inner walls by a specially formed pre-pulse. Electron beams with an opening angle of ∼40 mrad, exponential energy spectrum with maximum energy about 20 MeV, and a total charge of ∼0.2 nC are experimentally detected.
Polarisation gating technique in nonlinear Compton scattering: effect of radiation friction and electron beam nonideality
Authors: Valialshchikov M.A. , Kharin V.Yu. , Rykovanov S.G.
Published: August 2021

We discuss the effect of radiation friction and quantum recoil on the parameters of a gamma comb with narrow spectral peaks, arising when use is made of laser pulses with time-dependent polarisation, which reduces significantly the ponderomotive broadening of harmonics. A detailed numerical study of the contribution of the electron beam nonideality to the observability of the effect is presented.
Laser induced damage threshold and incubation effects of high-power laser system optics
Authors: Fourmaux S. , Kieffer J.C.
Published: August 2021

We present a laser induced damage threshold (LIDT) measurement technique where a mm-diameter non-Gaussian laser beam is used. This allows both a large number of measurements points and a large range of fluence to be sampled with a single measure. The method is used in-situ, inside the laser radiation – matter interaction vacuum vessel used for high power experiments with a 100 TW-class laser system. With our 2.5-Hz repetition rate laser system, the well-known incubation effect is observed where the laser damage threshold on the optics decreases with increasing number of laser shots. The incubation effect is studied with 22-fs laser pulses at a laser 2.5-Hz nominal repetition rate with several optics like dielectric mirrors and gold compression gratings irradiated by up to 9 × 103 laser shots.
An alternative broad vegetation hierarchy for eastern New South Wales, with application for environmental planning and management
Authors: Gellie Nicholas J. H. , Hunter John T.
Published: August 2021

Many previous vegetation description and mapping programs have highlighted the need for a hierarchical classification that easily translates from regional through to international scales. Often programs have not selected appropriate levels of vegetation classification and mapping for management purposes. Here, we provide an alternative broad vegetation classification at the macrogroup level in the international vegetation classification for eastern New South Wales (NSW) that could be applied in regional and local environmental planning and management. Existing aerial photographic interpretation (API) floristic and canopy maps available for eastern NSW were collated and reclassified and incorporated into a unifying dataset of macrogroups, which also included types dominated by exotic vegetation such as exotic plantations. There we identified, in total, 71 macrogroups across eastern New South Wales (NSW) of a total of 85 identified for NSW mapped at 1:25 000 scale, or finer, in the following three sections: north-east, Sydney basin and central west, and southern coast and Snowy Mountains. These were then amalgamated into a single remnant vegetation map covering 23 525 280 ha. This alternative broad vegetation hierarchy provides a reliable and overt vegetation classification and mapping dataset that can easily incorporate future revisions as new mapping data become available.
New insights into the effect of NdhO levels on cyanobacterial cell death triggered by high temperature
Authors: Zhao Jiaohong , Jiang Yuanyuan , Tian Yuhao , Mao Jun , Wei Lanzhen , Ma Weimin
Published: August 2021

NdhO, a regulatory oxygenic photosynthesis-specific subunit, is close to the ferredoxin-binding site of cyanobacterial NDH-1, and its levels are negatively associated with the rates of cyclic electron transfer around PSI mediated by NDH-1 (NDH-CET). However, the effect of NdhO levels on cyanobacterial cell death triggered by high temperature remains elusive. Here, our results uncovered a synergistic effect of NdhO levels on the cell death and reactive oxygen species (ROS) accumulation when cyanobacterial cells grown at 30°C for 1 day were transferred to 45°C for 2 days. Such synergistic effect was found to be closely associated with the activities of NDH-CET and CO2 assimilation during high temperature. Collectively, we propose that the effect of NdhO levels on the cyanobacterial cell bleaching and cell death triggered by high temperature is a result of influencing production of ROS by NDH-CET, which is considered to be vital to balance the ATP/NADPH ratio and improve the Calvin-Benson cycle.
Developmental HCN channelopathy results in decreased neural progenitor proliferation and microcephaly in mice
Authors: Schlusche Anna Katharina , Vay Sabine Ulrike , Kleinenkuhnen Niklas , Sandke Steffi , Campos-Martín Rafael , Florio Marta , Huttner Wieland , Tresch Achim , Roeper Jochen , Rueger Maria Adele , Jakovcevski Igor , Stockebrand Malte , Isbrandt Dirk
Published: August 2021

Significance

Impaired cell cycle regulation of neural stem and progenitor cells can affect cortical development and cause microcephaly. During cell cycle progression, the cellular membrane potential changes through ion channel activity and tends to be more depolarized in proliferating cells. Hyperpolarization-activated cyclic nucleotide-gated cation (HCN) channels, which mediate a depolarizing current in neurons and cardiac cells, are linked to neurodevelopmental diseases and also contribute to the control of cell cycle progression and proliferation of neuronal precursor cells. In this study, HCN channel deficiency during embryonic brain development resulted in marked microcephaly of mice with impaired HCN channel function in dorsal forebrain progenitors. The findings suggest that HCN channel subunits are part of a general mechanism influencing cortical development in mammals.
Tradition, modernity, and Chinese masculinity
Authors: Feng Dezheng (William) , Yu Mandy Hoi Man
Published: August 2021

This article examines the multimodal construction of ideal manhood in male participants’ self-introduction videos in a Chinese reality dating show. A framework is developed to model identity as evaluative attributes and to explicate how they are constructed through linguistic and visual resources. Analysis of 91 videos shows two versions of idealized Chinese masculinity, namely, modern masculinity (mainly embodied by participants who have won a date), and traditional masculinity (mainly embodied by participants who have not won a date). Modern masculinity highlights career-oriented qualities, socio-economic status, and luxurious lifestyles, while traditional masculinity highlights family values, skills in Chinese cultural heritage, and class mobility. The findings provide new understandings of the complexity of Chinese masculinity in the dating show context, which reflects the influence of capitalist globalization on the one hand, and the government’s attempt to govern public conduct and morality on the other.
A corpus-based study on contrast and concessivity of the connective ‑cimanin Korean
Authors: Lee Hye-Kyung
Published: August 2021

Providing a corpus-based analysis of the contrastive connective -cimanin Korean, this study demonstrates that global connections are as frequent as local connections as opposed to previous literature. In representing various senses possible with a -cimanconnection, this study adopts a fuzzy representation, where meanings range from conceptual to discoursal. The identified meanings include explicit contrast, denial of expectation, speech act hedges and idiomatic expressions. The fuzzy representation is supported for at least two reasons. First, categorization of some cases is often blurred. Second, it can better capture the relatedness of various meanings whose enduring sense concerns ‘contrast’. It is further revealed that interpretations of-cimanphrases are compositionally made with co-occurring linguistic units. The “pragmatic” meanings of-cimanconstructions are explained in terms of different levels of representations in which the contrast occurs. We further investigate the possibility of-cimanas a stance/discourse marker with accompanying expressions.
AP-PACVD plasma printer: investigating the influence of gas flow rates to printing resolution in parallel with CFD simulation
Authors: Acharya Kishor , Bulou Simon , Gaulain Thomas , Choquet Patrick
Published: August 2021

A coaxial shaped atmospheric pressure plasma torch has been used to deposit the millimetric scale plasma polymer. A detailed experiment has revealed the appearance of three different kinetic regimes with distinct coating morphology: no deposition, circular dot and circular ring formation. The ratio of precursor carrier gas flow to the plasma species carrier gas flow has been identified as crucial factor to separate the three regimes. Further experiments regarding the influence of precursor mass fraction on the dimension and deposition rates has been performed for a circular dot regime to get more insights into the coating shape, size and volume and its relation to gas flow dynamics. A side by side computational fluid dynamic simulation coupled with species transport module has been performed to understand the influence of flow dynamics on coating morphology. The appearance of recirculatory vortices in-between the nozzle and substrate and its role on confinement of precursor at specific region and mixing of plasma species to precursor has been highlighted. A good correlation in between the diameter of thus coated plasma polymer in circular dot regime and the simulated confinement zone is here reported.
Realization of Low Cost Footwear Integrated Step-Counting Device for Health Monitoring System
Authors: Aryan  , Mittal Poornima
Published: August 2021

In this paper, a piezoelectric sensor is used to sense the pressure generated when steps are taken. The output voltage generated by the piezo electric sensor is passed through a cascade combination of two voltage comparators, (LM 358 AND 741), the output of which is HIGH(5V) when a piezoelectric sensor is pressed and the voltage across the sensor goes above the threshold. The output of the comparators is then fed to the counter circuit (implemented using 4026 IC), which counts the number of times the output is high/steps are taken. Finally, the output is exhibited on a 7-segment display common cathode display.
Prediction Accuracy Model Aiming to Improve Prediction Accuracy in Congenital Heart Anomaly Detection using Hybrid Feature Selection with Modified Particle Swarm Optimization Approach
Authors: Nabi Dr. Shaik Abdul , Ramya Laxmi K.
Published: August 2021

Heart Disease is one of the primary causes of mortality and morbidity in the Globe since the 19th Century. Most of the Globalized Multi-Specialty Hospitals are not able to control and governed by emerging technologies, at the same time, the death rate escalates day by day in addition to Covid-19 is a multifaceted state. Heart disease classification involves identifying numerous health problems and sickness symptoms of ones’ individual with significant feature selection, there is misclassification probability that could be very high and priceless. There are many diverse methods were designing for heart disease prediction systems in earlier days, even though it is unsolved and rising the death rate. As observed by many research groups, PSO is an intensive computational and inspired biologically inspired algorithms like Genetic Algorithms (GA) has a proven track record to handle computationally complex problems with competence for predicting heart diseases. This research contribution through the proposed model downs the computation time and increases the accuracy. The high-level comprehensibility, predictive accuracy are good and desired through this Intelligence Hybrid Approach (IHP) to reduce Heart attacks and control the death rate.
Mutual Information-Based Optimum Metrics Identification in Symmetry-Based Brain Abnormality Detection
Authors: Al-Azawi Mohammad A. N.
Published: August 2021

In our previous studies, we showed that brain abnormalities can be detected by comparing the features extracted from the two lobes with each other. Based on this, many metrics, such as those extracted from colour or texture features, have been extracted and used. The large number of extracted metrics posed a challenge in terms of how important each metric is. In this research, we use the mutual information content to measure the importance of the metrics and their influence on the classification process as it gives an indication of how the output and each input are related to each other. The algorithm was applied to 366 images, from which eleven metrics were extracted and studied. Random forest classifier was used as it was proven that it gives the highest accuracy. The obtained results showed that 30% of the features can be eliminated without a significant effect on the accuracy.
Optimizing Neural Network Parameters For Effective Classification of Benign and Malicious Websites
Authors: Balamurugan P. , Amudha T. , Satheeshkumar J. , Somam M.
Published: August 2021

Bio-inspired algorithms are the most powerful way to solve optimization problems. The objective of this paper is to use optimized network parameters for website classification and the efficiency of Neural Network is improved by optimized network parameters. The network parameters are optimized using two bio-inspired algorithms: Particle Swarm Optimization (PSO) and Cuckoo Search (CS) and the optimized parameter values are used with two neural network models, a standard Multi-Layer Feed Forward Network with Backpropagation (BPN) and Radial Basis Function (RBF) Network. Security is one of the major concerns in this digital era. There are numerous websites, which are potentially risky in spreading malicious files. It is difficult to detect such websites. In this work, Neural Network is used to classify the websites as benign and malicious. The proposed neural network models are tested with URL dataset. The experimental results are assessed in terms of Error reduction, training time and classification accuracy. The experimental result shows that the optimized network parameters have given good improvement in classification with faster convergence.
IoT based Agri Soil Maintenance through Micro-Nutrients and Protection of Crops from Excess Water
Authors: Kanakamedala Phaneendra , Reddy Bhumireddy Anil , Sri Nannapneni Kavya , Nadakuditi Bangari , Jayanth Kumar K.
Published: August 2021

The productivity of the crop depends on the soil, fertilizers, and water. The fertilizers provide micronutrients for vegetable farming like nitrogen, zinc, and others. To meet the increasing demand for food, crops should be able to withstand the adverse effects produced by the environment and unpredictable sources. The structure of smart agriculture is similar to networks, which are designed in 3 layers. Sensor layer to get information about various parameters, products, and operating environment. Transport layer to communicate the obtained information in between the various devices and as well as to and from a remote server. Application layer to analyse, visualize and predict the data for further actions to be implemented. In the proposed system, it uses multilinear regression to predict the water levels and micro-nutrients that are excess for the crop cultivation because farmers need analog data, not digital data. So that they can take necessary precautionary steps to protect the field from getting damaged.
The use of multi-agent systems for modeling technological processes
Authors: Petrovich Bobkov Sergey , Aleksandrovna Astrakhantseva Irina
Published: August 2021

The article is devoted to the issues of using discrete simulation models for modeling some basic technological processes. In the scientific work, models in the form of multi-agent systems have been investigated, which allow us to consider a continuous environment as a set of interacting elements (agents), the behavior of which obeys local functions. The authors describe the basic techniques and general methodology for the development of deterministic agent-based models. The paper considers the use of multi-agent systems for modeling thermal conductivity, taking into account the nonlinearity of the process, in homogeneity of the material and the presence of volumetric heat sources of variable power in it. The obtained scientific results are in good agreement with the generally accepted classical approaches and do not contradict the provisions adopted in the theory of thermal phenomena.
Smart Grid model verification method
Authors: Voinov Artem , Senokosov Ilya
Published: August 2021

This paper considers a method for verification and subsequent modification of the Smart Grid during design stage. For automated use, it is required to create a network template, the elements of which would be present in any particular case of implementation. This role in our method is performed by the Smart Grid ontology. Verification for the network created by designer is carried out through comparison with abstract ontology model. When differences are found (e.g., lack of desired control system), the solution search occurs among the rules in Prolog language for this situation, and the Smart Grid model created by designer is translated into Prolog description. If rules are found, then they are applied, modifying the model created by designer. If not – return the model to designer for improvement. The last stage is the processed ontology model translation back to initial description. This method is considered on the example of abstract network model.
Logical approach to the analysis of economic development programs
Authors: Kanametova D A , Lyutikova L A
Published: August 2021

The present paper proposes a logical model for building an effective economic development programmer. It is built on the basis of existing programs, which are not the best in terms of their strategic implementation, but can improve some economic indicators. As part of our model, these programs will be considered as elements of a logical scheme that should implement a development program with optimal indicators.
Determination of the formation model of the phase concentration field along the section of the turbulent flow of hydrotransport using information technologies
Authors: Ilhamov Kh Sh , Arifjanov A M , Narzullaev D Z , Abdurakhmanov B A , Shadmanov K K
Published: August 2021

The problem of increasing the reliability and durability of hydrotransport facilities is one of the most important national economic tasks. The formation of the concentration field of the second dispersed phase, which is nonuniform over the cross section, is studied by the turbulent stationary motion of the mixture in a horizontal cylindrical pipe and the transporting ability of the flow is estimated. The article proposed a mathematical model and a method for calculating the concentration field of solid particles along the depth of the flow using information technologies, where the formation of the concentration field is first determined through the size of solid particles when a two-phase mixture moves in a horizontal cylindrical pipe. Also, in this model of mixture motion, the coefficient of the force of interaction between the phases is determined depending on the concentration distribution. The problem is solved by a numerical method using the integrated system for mathematical calculations MathCAD. Investigating the numerical results of the problem, the nature of the formation of the concentration field at various values of the saturation of the flow with solid particles and which makes it possible to estimate the size of these particles taking into account the turbulence of the flow. The implementation of the developed mathematical models and recommendations will make it possible to predict the transporting ability of a two-phase flow in pressure systems, and help to find solutions for spatial hydrotransportation and irrigation and drainage systems.
Application of remote sensing technologies for studying urban forests in conditions of technogenic impact
Authors: Yu Zengina T , Kirillov S N , Slipenchuk M V , Uskova K A
Published: August 2021

In this work, an attempt was made to assess the possible change in the photosynthetic potential of the forests of New Moscow, depending on the degree of their remoteness from the territories with technogenic impact, based on the data of remote sensing of the earth. Because of constructing the time series of the spectral index NDVI, the value of the photosynthetic potential of homogeneous forest areas at different distances from the old borders of Moscow was estimated. Studies have shown that the average NDVI values of forests increase with distance from the borders with Old Moscow. The lowest NDVI values (0.70) are typical for forests located at a short distance from Moscow. In the central part of New Moscow, the index is 0.72, and the highest NDVI values (0.75) are observed within the settlements located in the south near the border with the Kaluga region.
Network traffic analysis based on machine learning methods
Authors: Vulfin A M , Vasilyev V I , Gvozdev V E , Mironov K V , Churkin O E
Published: August 2021

Comparison of mining algorithms in the problem of detecting malicious network activity based on machine learning models is performed. A structural diagram of a system for analyzing network traffic in an industrial network based on machine learning methods has been developed. On one of the known datasets (CICIDS17), a series of experiments was carried out on preliminary analysis and preprocessing of features, highlighting the most significant features and building final models of classifiers. The f1-measure score for the committee of classifiers on the test sample is 0.967.
Modelling of the evolution of the multi-behavioural dynamics from the regulatory climate theory
Authors: Kolokolov Yu V , Monovskaya A V
Published: August 2021

The regulatory ability in the local climate dynamics to evolve in accordance with the environmental changes is modeled in the paper. The specialized software provides the following research program: to calculate the solutions of the nonlinear nonstationary multi-behavioural model of the dynamical system with variable structure; to determine the nonlinear dynamics regularities on the basis of these solutions; to reconstruct these regularities by processing the meteorological observations; to solve the inverse problem of building the multi-behavioural portraits of local climate dynamics by use of the reconstructed regularities. Thus factually realized and potential evolutional vacancies of the local dynamics are visualized in the form of the multiple attractors. The physical basis of the research originates from the regulatory climate theory, in accordance with which the local climate dynamics is conceptually considered as the dynamics of the solar energy converter under the astronomically forced hysteresis control with double synchronization. Here landscape and ecological relations are taken into account via the adaptation unit, and the recent dynamics is compared with the one observed as far as possible distant in time. So, structural modifications within the multi-behavioural portrait of local climate dynamics are revealed and crucial evolutionary tendencies are demonstrated.
The impact of digital education transformation on technical college teachers
Authors: Tsarapkina Ju M , Anisimova A V , Gadzhimetova B D , Kireycheva A M , Mironov A G
Published: August 2021

The transformation of the educational environment based on digital technologies contributes to the emergence of new forms and methods of work of teachers. The search for new learning technologies in the digital educational environment contributes to the motivation of teachers to improve themselves in their professional activities. The authors investigate the impact of the use of electronic teaching tools on the motivation for professional activity of college teachers. In the course of research activities, the authors have created a number of courses on a digital educational platform that can be used by teachers of various disciplines. The article describes the advantages and disadvantages of working with these digital resources. The survey results obtained in the course of the study indicate that the majority of teachers are satisfied with their work in college, but they note the insufficient equipment of pedagogical activities with digital means. Also, almost two-thirds of the respondents strive to use innovative teaching aids in their activities. Using the methodology of K. Zamfir in the modification of A. Rean, the authors revealed an increase in the high and medium level of motivation of professional activity among teachers.
Study on Fracture Parameters of Stress Corrosion Cracking Tip of AA6082 Alloy at the Microscopic Scale
Authors: Song Jia , Fan Ding , Wu Wenheng , Lei Liming , Zhang Liang , Gao Zhibin
Published: August 2021

A two-dimensional finite element model is used to explore the fracture parameter in the tip region of stress corrosion crack (SCC) of AA6082 alloy. Based on the ABAQUS code, we investigate the effect of oxide film’s yield stress on the Mises stress and equivalent plastic strain (PEEQ) in the crack tip. The results show that as the yield strength of oxide film increases, the Mises stress and PEEQ of base alloy in crack tip area both decrease, and the stress of oxide film in crack tip also reduces, but the strain increases. This is because the oxide film bears more load, so the load on the base alloy of the crack tip becomes smaller, resulting in a reduction in the stress and strain on the base.
Mutual Effect of Oxide Peg Growth and Reactive Element Distribution in Ti-doped CoNiCrAlY Alloys
Authors: Yang Liang
Published: August 2021

CoNiCrAl alloys are widely employed as a high temperature resistant material in thermal barrier coating (TBC) systems. In such materials, the adherence between the thermally grown oxide (TGO) Al2O3 scale and the alloy is strengthened by oxide pegs formed by dispersed oxide addition or the oxidation of doped reactive elements. In this study the addition of Ti as the reactive element to a CoNiCrAlY alloy has been addressed. We investigated the mutual effects between Ti and the oxide pegs in alloy samples that had been subjected to a cyclic oxidation process. The alloy with a higher Ti content exhibited a uniformly fine β-phase and fewer voids at the scale/alloy interface, the scale growth rate was lower for Ti-containing alloys. In addition, the formation and growth of oxide pegs led to an irregular distribution of Ti in the scale and at the scale/alloy interface, which resulted in local variations in the features of the scale, with fewer voids and a thinner scale at the sites that are far from the oxide pegs. Meanwhile, the incorporation of Ti to the Y-rich oxide led to an increase in the bonding strength between the peg core and the Al2O3 sheath.
Theoretical Analysis and Experimental Study on Rail Dynamic Load of Electromagnetic Launcher
Authors: Liu Jingang , Dong Zhiqiang , Su Zizhou , Huang Kai , Ren Ren , Zhang Tao , Chen Yanhui , Li Shili
Published: August 2021

In the course of electromagnetic launch, the rail deflection deformation seriously affects the service life and launch accuracy of the orbit. In order to reduce the deflection deformation in the process of orbital launch, based on the principle of electromagnetic emission, simplifying the orbit to Euler-Bernoulli beam, built moving load working conditions of the electromagnetic moving load model, using the electromagnetic launcher bore related structural parameters and material parameters for the rail electromagnetic theory analysis and calculation, the analysis results show that under the condition of the same peak current, rail the biggest position in midpoint deflection deformation; under different peak current, the deflection of the midpoint of the rail increases non-linearly. The deflection of the rail can be effectively reduced by increasing the stiffness of the elastic support. According to the above theoretical analysis results, an electromagnetic launching device was developed. The experimental comparison results show that the deflection deformation is reduced by 42.86% and the critical launch velocity is increased by 6.86% with the increase of support stiffness.
Overview of Robotic Reducer Testing Technology
Authors: Lin Yuanchang , Sun Wencheng , He Guotian , Zhang Zhenjun
Published: August 2021

As a high-performance precision reduction transmission equipment with large transmission ratio, high transmission efficiency, high transmission accuracy, stable transmission and low noise, reducer has been widely used in many fields such as industrial robots. The definition of the reducer is studied, the development history of the reducer is briefly introduced, and the classification and characteristics of the reducer are summarized, including traditional reducer, RV reducer, harmonic planetary reducer and cycloid reducer, A new generation of reducer and influencing factors such as transmission accuracy, transmission efficiency, backlash, torsional stiffness, noise, and assembly. The problem of precision reducer is analyzed, and finally the application and development trend of reducer are studied.
A Numerical Study on Plane Contact Problem Involving Inclusions
Authors: Xie D D , Zhu K , An Y H , Li P , Jin X Q
Published: August 2021

Hertz’s contact theory is widely used in elastic solid contact problems. In this paper, the applicability of Hertz’s contact theory in conformal contact problems was examined. Taking deep groove ball bearing and the outer raceway model as an example, both the FEM analyses and the theoretical studies were conducted. It is found that when the radius coefficient of groove curvature is greater than 0.55, Hertz’s theory can be practically applied for conformal contact. Contact problems of rolling bearings are generally solved by Hertz’s contact theory without considering inclusions and inhomogeneities in the material. In this paper, inclusions are presented in the contact analyses, and the corresponding elastic field distribution of the contact-inclusion model is investigated by using the finite element method.
Non-uniform Kirigami Enhances Films Conformability
Authors: Wang Haotian , Han Yafeng
Published: August 2021

Developing films with great conformability has become a research hotspot in many fields. The conventional method to enhance conformability is to make the film thinner and more compliant, which usually compromises the strength of the structure. For example, developing functional medical bandages that can perfectly conform to the skin surface during cyclic bending of the joints is still a considerable challenge. In this paper, we propose a novel non-uniform kirigami to make the film achieve the same non-uniform auxetic (negative Poisson’s ratio) deformation as the skin around the joint area. By mapping the corresponding unit cells to the target surface, the surface can easily achieve the same deformation as the target skin without any alterations in its thickness or adhesion. As the obtained non-uniform kirigami film structure has the same deformation behavior as the target skin surface, the conformability of the structure can be guaranteed during the entire rotation process of the joints. Moreover, the proposed film is also expected to be used in novel biomaterials, such as smart bandages, skin scaffold, etc.
Analysis and Comparative Study on the Pushing Effect of Screw Rod with Different Structural Parameters
Authors: Zhao Keli , Yu Aiwei , Liu Yuqi , Zhao Qingxi , Man Zunhai
Published: August 2021

The computational fluid dynamics software fluent is used to calculate and study the hydrodynamic performance of the rotating screw in the water flow field. First, UG is used to establish different parameter calculation models, and then the slip grid method in the fluent is used to calculate the flow field state, thrust and torque of the simulated screw rod under different blade angles and number of blade turns, calculate through the above data obtain the screw rod’s pushing efficiency, and obtain the best structural parameters of the screw rod when the best pushing effect is achieved through the comparison of experimental data.
Investment Casting Simulation and Analysis of Shell AlSi11 Alloy Part
Authors: Miao Liqin , Tang Zhengwei , Zhang Dashun , Meng Fanjun , Wang Jing , Li Xueguang
Published: August 2021

Shell investment casting of AlSi11 alloy was stimulated in this paper. The shell model of AlSi11 alloy casting was established using UG three-dimensional drawing software, and the solidification process of the inner material of the shell was numerically simulated based on the ProCAST software. The final analysis shows that the entire solidification process is solidified layer by layer, and the filling time of the material inside the shell is 14.70s. After solidification and cooling, the shrinkage volume of the internal defects of the material is 7.80 square centimeters, the average shrinkage rate is 17.90%, and the pore volume is 1.70 square centimeters. Through the simulation and analysis of the solidification process, not only can we find out the shrinkage cavities generated in the solidification process, but also can effectively reduce production costs and improve efficiency.
Factors Affecting the Tooth Surface Finish of the Inner Gear Rings for Coal Cutters
Authors: Zhao Liyuan , Yuan Yuedong , Chen Long , Ma Rui
Published: August 2021

In order to analyze the reason why tooth surface finish of the inner gear rings for coal cutters can not meet the standard requirement, a series of experimental studies are carried out on the gear-shaping cutter and the corresponding cutting parameters. It is found that the tooth surface finish can not reach the standard after machining with each cutting parameter by using a M2 high-speed steel cutter. Using a M42 high-speed steel cutter + Balchas coating, the tooth surface finish under each cutting parameter can meet the standard requirement. Combining with the requirements of machining efficiency and tooth surface finish, the matching cutting parameters are proposed. This study has guiding significance for improving the tooth surface finish of the inner gear rings for the coal cutters.
Design of Automatic Claw Changing Robot for Intelligent Sorting System
Authors: Song Zhilan , Wen Ping , Ran Wenxue
Published: August 2021

In recent years, China’s express business volume has steadily increased, which has greatly increased the operation volume and complexity of sorting operations. However, the current logistics sorting process is still in manual or semi-automatic sorting, and the technology in the process of express sorting cannot match the surging order volume in the express industry. And with the rapid development of e-commerce and the increasing personalized demand, customer orders gradually tend to be multi-variety, small batch, multi-frequency, and then put forward higher requirements for the flexibility of the sorting system. In this paper, aiming at the low sorting efficiency caused by the inconsistent standards of goods in the sorting process, based on the idea of automatic tool changing in machining center, a hand changing grasping robot is designed, which includes the structure of cluster, “claw library” and robot automatic claw changing structure. The design can realize the multi-purpose of one machine and improve the flexibility of the sorting system.
Study on the Control of Micro-Environmental Parameters in Long Distance Laser Interferometry
Authors: He Yan , Zhu Yurong , Nie Hongfei
Published: August 2021

Fluctuation in environmental parameters has become an important factor affecting the performance of ultra precision measurement. Aiming at the long-distance and high-speed laser interferometer measurement system, a method combining structure design and closed-loop control is proposed to reduce the measurement error caused by environmental parameters. The uniform pressure structure is designed, and the control system of micro environmental parameters is established. The simulation and experimental research on the uniformity of temperature and pressure on the optical path measured by laser interferometer are carried out. The simulation and experimental results show that this method can achieve temperature uniformity and stability above 0.01°C and pressure uniformity and stability above 1Pa, and can be widely used in micro environment parameter control of long-distance ultra precision measurement.
Design and Fabrication of a Novel High Power THz Slow Wave Structure Based on MEMS Technology
Authors: Zheng Heng , Yao Jinyuan , Zheng Rui , Zhang Qi , Lu Xichi
Published: August 2021

With the development of TWT in terahertz band, the size of TWT is greatly reduced and the power gain is also reduced. In order to improve the performance of traveling wave tube (TWT), an E-plane and H-plane tapered folded waveguide slow wave structure operating at 0.34THz is designed. In order to reduce the RF loss, a gradual ridge is added to the E-plane ridge. Compared with other ridge loaded structures, the coupling impedance of this structure has been significantly improved, and it has better dispersion characteristics and higher maximum output power. According to the electromagnetic simulation results, under the condition of 16.8kV, 50mA banded electron beam, the maximum output power of the folded waveguide can reach 65.1w, the power gain can reach 31.8db, the 3dB working bandwidth can reach 12GHz, and the electronic efficiency can reach 7.75%. Finally, a complete DRIE process for processing slow wave structure is explored. The slow wave structure is fabricated by combining silicon with non-silicon.
Research on Face Recognition Based on Improved Convolutional Neural Network Using Raspberry Pi
Authors: Ning Lingyi , Huang Zhikai , Xi Xianchang , Zhang Yang
Published: August 2021

In this paper, a face recognition system has been designed using Raspberry Pi based on convolution neural network technology. Convolution neural network that using OpenCV (open source computer vision library) to realize real-time face recognition and feature extraction. The difficult and important problem in deep learning network is that it could be over fitting very easily. In order to alleviate the over fitting phenomenon and improve the accuracy of face recognition, the dropout technology of convolutional neural network had been employed to improve the recognition accuracy and ensure the robustness of face recognition. The results of experiments show that our methods has the advantages in the computer time and recognition rate for the low construction cost, simple structure and strong portability. The accuracy of face detection for static and dynamic images using Raspberry Pi is above 85% in our testament.
X-ray Computed Tomography Method for Measuring Matric Suction of Micro-Sheet Materials Mixed Cs2SO4
Authors: Sun Yinlei , Tang Liansheng
Published: August 2021

In this paper, the X-ray computed tomography method was applied to measure the matric suctions of the glass-sheet samples. With the contributions of Cs2SO4 solution, the distributions of water among glass sheets were distinctly observed. The shape of the liquid bridges between the glass sheets are not simple circular ring, but rings with the triangular or quadrangular projective planes. Cs2SO4 resulted in the coefficient surface tension of the solution decreasing, which is the main reason that the tested values of matric suction were slightly higher than calculated. Overall, the differences between tested and calculated values are less than 3%, which testified that X-ray computed tomography method for measuring matric suction is feasible. The significance of this work is X-ray computed tomography method could be applied in unsaturated clay soil constituted by sheet particles.
Image Classification for Soybean and Weeds Based on ViT
Authors: Liang Jingxin , Wang Dong , Ling Xufeng
Published: August 2021

Abstracts. In this paper, ViT deep neural network based on self-attention mechanism is used in classification for images of soybean and weeds. Firstly, the overall image is split into multiple tiles; with each tile regarded as a word, the whole image is regarded as a sentence, which can be used for image semantic recognition by natural language processing technology. We designed a ViT network with sequence length of 50, embedded dimension of 384, and self-attention module layers of 12. With soybean weed classification dataset, the network is trained, verified and tested. Experimental results showed that ViT network is superior in classification on dataset of soybean and weeds, with excellent generalization capability.
Research on Oblique Penetration of Projectiles into Targets of Different Materials
Authors: Zhang Xiaojing , Yao Wenjin , Li Wenbin , Wang Xiaoming , Zhu Xintao
Published: August 2021

In order to study the trajectory deflection of projectile penetrating obliquely into different materials, the Lagrange algorithm of LS-DYNA was used to simulate the three-dimensional model. The impact angle of projectile is 70°, the concrete target and the soil target are penetrated respectively. The state of the target, the strain nephogram and the stress nephogram of the target under the maximum overload are obtained. The curves of penetration depth, penetration velocity, overload and energy are analyzed. The results show that: in oblique penetration, the projectile’s trajectory deflects more in the process of entering the concrete target, and then deflects less; the trajectory deflection of the projectile is small in the process of entering the soil target and a certain distance after it, but it becomes larger when it is fast out of the target.
Energy Management Control of Fuel Cell Electric Bus Basing on Fuzzy Rule
Authors: Wang Renguang , Hao Dong , Zhang Yanyi , Meng Xiangfei
Published: August 2021

A hybrid fuel cell bus was taken as the research object. Firstly, the structure and characteristics of fuel cell bus power system were introduced, and the power system parameter design was completed according to the vehicle parameters and performance design goals; Secondly, in order to improve the durability of fuel cell and the economy of power system, a three input single output fuzzy energy management control strategy was designed, with the fuel cell power increment selected as the control variable to coordinate control fuel cell power output and change; Finally, the effectiveness of the fuzzy control strategy was verified basing on MATLAB/Simulink platform, the results showed that the fuzzy control strategy can control the SOC of battery reasonably and effectively, while is better than the power-following energy management strategy in terms of power system economy and fuel cell durability.