Journal of Northeastern University(Natural Science)

Adaptive Multi-scale Cost Volume Construction and Aggregation for Stereo Matching

PANG Yan-wei， SU Chang， LONG Tao

2023, 44 (4): 457-468. DOI: 10.12068/j.issn.1005-3026.2023.04.001

Abstract ( 738 )

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Stereo matching based on convolutional neural network has made great progress. Existing methods still suffer from mismatching in weak texture regions， details and edges. Based on the cost volume commonly used in stereo matching， a stereo matching network with adaptive multi-scale cost volume construction and aggregation was proposed. Firstly， the proposed method fully fused the multi-scale features to obtain the recombined features. Then， a learnable feature enhancement module was used to recover the detail information for multi-scale cost volumes. Finally， after intra-scale aggregation based on global attention， an adaptive multi-scale weighting method was proposed for inter-scale aggregation to screen the matching features adapted to the disparity regression of each scale. Massive experiments on the SceneFlow and KITTI2015 datasets show that the proposed method achieves competitive performance with smaller network size which verifies the effectiveness of the proposed method.

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Delay Multiply and Sum Beamforming Algorithm Based on Virtual Source

WANG Bao-yu， LIU Rui-lin， ZHANG Miao， ZHANG Shi

2023, 44 (4): 469-475. DOI: 10.12068/j.issn.1005-3026.2023.04.002

Abstract ( 574 )

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In order to improve the imaging resolution in ultrasonic sequential beamforming based on virtual source， a delay multiply and sum beamforming algorithm based on virtual source， namely VS-DMAS algorithm， is proposed. The algorithm introduces the idea of DMAS into the second stage of sequential beamforming based on virtual source， taking advantage of the characteristics of multiplication coupling operation in DMAS algorithm， with the consideration of the coherence between signals， in order to suppress the generation of artifacts in low echo areas and improve the resolution and contrast of ultrasonic imaging. The point target phantom simulation and entity data imaging experiment are carried out. The results show that compared with the conventional focusing method， VS-DMAS algorithm has lower side lobe and narrower main lobe and can better separate the point target from the background noise， with the increase of depth as well as a higher imaging resolution. And with the appropriate increase of p value in the algorithm， the imaging resolution and contrast are improved to a certain extent.

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Classification of Pulmonary Nodule by Combining Long-Distance Channel Attention and Pathological Feature

DING Qi-chuan， WANG Li， LIU Cheng

2023, 44 (4): 476-485. DOI: 10.12068/j.issn.1005-3026.2023.04.003

Abstract ( 512 )

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Aiming at the common problems of existing deep learning networks， such as lack of correlation of long-distance feature channels and network self-extraction features obliterating the dominant pathological features of pulmonary nodules. Firstly， by combining channel attention and spatial attention， an attention module LCA (long-distance channel attention) that can effectively establish the correlation of long-distance feature channels is proposed. Secondly， the dominant pathological features such as pulmonary nodule diameter， texture and calcification are fused with their depth features to enhance the importance of these dominant features. Finally， a feature extraction network DLCANet (dual-connected long-distance channel attention network) and a classifier model MARTM (multiple additive regression tree model) are built. The classification experiments are carried out on the datasets LIDC-LDRI and LUNA16. Compared with the benchmark model DPN (dual path network)， the accuracy rate is increased by 3.63%， the false positive rate is decreased by 8.66%， and the overall performance is better than those of current mainstream models.

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Modeling and Analysis of Infectious Disease Transmission Considering Protection and Isolation

ZHANG Lu-wen， LIU Hong-juan

2023, 44 (4): 486-494. DOI: 10.12068/j.issn.1005-3026.2023.04.004

Abstract ( 549 )

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Based on the SEIR model， two compartments for self-protection and isolation are introduced， and a more general infectious disease transmission model is proposed. Through qualitative analysis of the model， the basic reproduction number of the model is calculated， and the local asymptotic stability of the disease-free equilibrium point and the endemic equilibrium point of the model is analyzed through eigenvalue theory and Routh-Hurwitz criterion. The numerical simulation and fitting results of COVID-19 virus show that the proposed SEIQRP model can effectively describe the dynamic transmission process of the infectious disease. In the model， the three parameters， i.e. protection rate， incubation period isolation rate， and infected person isolation rate play a very critical role in the spread of the disease. Raising people’s awareness of self-protection， focusing on screening for patients in the incubation period， and isolating and treating infected people can effectively reduce the spread of infectious diseases.

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Two-Stage Homogenization of Al-Zn-Mg-Cu Alloy to Improve Al₃Zr Precipitation Processed by Twin-Roll Casting

WANG Zhao-dong， LI Xin-le， LI Yong， LU Bing

2023, 44 (4): 495-501. DOI: 10.12068/j.issn.1005-3026.2023.04.005

Abstract ( 536 )

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This study focused on the effect of homogenization on precipitation behavior and recrystallization of Al-Zn-Mg-Cu alloy with twin roll casting (TRC). Furthermore， the influences of Al₃Zr precipitation and recrystallization levels on mechanical properties and intergranular corrosion (IGC) resistance were evaluated. The results showed that compared to the single-stage homogenization， the first stage of two-stage homogenization provides higher driving force and greater number of heterogeneous nucleation sites， which enhances the precipitation of Al₃Zr. In addition， different heating rates also affect the precipitation of Al₃Zr. The slow heating rate is beneficial to refine the size of Al₃Zr and increases the quantity density and volume fraction of Al₃Zr particles. During the solution treatment， variations of f/r ratio of Al₃Zr phase leads to different recrystallization resistance， so the proportion of recrystallization structure and the number of large angle grain boundaries of the samples homogenized after the T6 treatments decrease. These microstructures and the corresponding distributions of Al₃Zr slightly affected the mechanical properties， while they significantly improved the intergranular corrosion resistance.

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Numerical Simulation and Experimental Investigation on Hot Rolling Process of 2195 Aluminum Alloy at Different Speeds

ZHU Qing-feng， YAN Bo， FENG Zhi-xin， ZUO Yu-bo

2023, 44 (4): 502-509. DOI: 10.12068/j.issn.1005-3026.2023.04.006

Abstract ( 620 )

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The effect of rolling speed on the hot rolling process of 2195 aluminum alloy with the same rolling schedule was studied by numerical simulation and hot rolling experiments. The results showed that the microstructure uniformity along thickness direction is affected by the rolling speeds while the distribution microstructure along thickness direction of plate with the rolling speed of 1.2 m/s is more uniform than that plate with the rolling speed of 0.3 m/s. And the numerical simulation result showed that the equivalent strain distribution along thickness direction of the plate with rolling speed of 1.2 m/s is more uniform than that plate with the rolling speed of 0.3 m/s， which is consistent to the distribution microstructure of the plates. The spreading of rolled plate is affected by the rolling speeds as the rolling schedule is consistent. The spreading of the plate with the rolling speed of 1.2 m/s is bigger than that of plate with the rolling speed of 0.3 m/s. The plate size of the numerical simulation is consistent with the plate size of rolling experiment. The numerical simulation results and the hot rolling experimental results keep in good agreement in rolling force， temperature change， final shape， and uniformity of deformation in the thickness direction.

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Characteristics of Phase Change Materials and Analysis of Thermal Properties

WUSIMAN Kuerbanjiang， DAI Xiao-ye， SHI Lin

2023, 44 (4): 510-516. DOI: 10.12068/j.issn.1005-3026.2023.04.007

Abstract ( 1173 )

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Phase change materials (PCMs) are the core media of energy storage for latent heat storage. Thus， screening of appropriate PCMs needs to take into consideration a variety of factors， whereas phase transition temperature， energy storage density and thermal conductivity are the most critical factors during assessment of feasibility for PCMs. As evident by summarizing and comparing the characteristics of different categories of typical solid-liquid PCMs， multi-high-performance compatible composite materials is the development direction for PCMs’ applications. Finally， based on the theoretical analysis， it concluded as that within the range of specified working temperature difference of 50℃， the heat storage density per unit mass of common PCMs is no longer correlated with it’s phase transition temperature when latent heat is ≥100kJ/kg， and the higher of phase transition temperature of PCMs is， the wider range of the effective output temperature can be obtained by the system， and more flexible output of system becomes. The larger the latent heat of PCMs is， the more stable the heat discharging efficiency of the system is while varying the effective temperature. Therefore， within the temperature difference of 50℃， the thermal energy storage system gains rather superior output performance with selection of PCMs under considering of it’s higher latent heat， competitive average solid-liquid specific heat and higher phase transition temperature.

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Microstructure Analysis of Mold Flux of Cao-SiO₂-Al₂O₃-Na₂O-MgO System for Ingot Casting

WANG Zhen， JIANG Mao-fa， LIU Cheng-jun， MIN Yi

2023, 44 (4): 517-523. DOI: 10.12068/j.issn.1005-3026.2023.04.008

Abstract ( 551 )

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In order to clarify the influence mechanism of chemical composition change on physical properties of mold flux for ingot casting， the microstructure of CaO-SiO₂-Al₂O₃-Na₂O-MgO system slags were analyzed via Raman spectroscopy. The melt structure analysis results showed that there are five silicon oxygen tetrahedral structures Q⁰_Si，Q¹_Si，Q²_Si，Q³_Si and Q⁴_Si and three aluminum oxygen tetrahedral structures Q²_Al，Q³_Al and Q⁴_Al in the slag. With the increase of basicity and the decrease of Al₂O₃ mass fraction， the tetrahedral structure with high degree of polymerization changes to low degree of polymerization， the number of non bridging oxygen in the slag increases and the degree of polymerization decreases. The physical property test results showed that the viscosity increases with the increase of Al₂O₃ mass fraction and decreases with the increase of basicity. The surface tension decreases with the increase of Al₂O₃ mass fraction and increases with the increase of basicity， which is consistent with the microstructure transformation behavior of slag. The effects of slag metal interfacial reaction on the microstructure， physical properties and behavior of slag entrapment are discussed.

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Molecular Dynamics Simulation on Effect of Sodium Chloride on Growth Habit of Gypsum Crystal

SUN Zhi-jie， SHI Pei-yang， FAN Lei

2023, 44 (4): 524-530. DOI: 10.12068/j.issn.1005-3026.2023.04.009

Abstract ( 566 )

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How to effectively control the growth behavior of gypsum crystal in solution system has become one of the urgent problems to be solved in desulfurization industry， and the effective information of crystal growth process can’t be detected online timely and effectively. In this work， molecular dynamics simulation (MS) was used to calculate adhesion energy， face-center distance and area of specific plane of gypsum crystal， to determine morphologically dominant crystal planes and surface structure， and to theoretically study the interaction mechanism between sodium chloride and the main growth planes. The effect of sodium chloride on the crystal morphology of gypsum was obtained through experiments， which was compared with the results of MS. Results showed that sodium chlorides have varied effects on each crystal planes of gypsum crystals， which further changing the crystal morphology of gypsum. The simulation results are consistent with the experiment. MS can provide a theoretical support for morphology control of gypsum crystals.

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Effect of Quick-Point Grinding Technological Parameters on Grinding Vibration Frequency

SHAN Quan， PAN Shuai， YU Xue-qiao， MA Lian-jie

2023, 44 (4): 530-535. DOI: 10.12068/j.issn.1005-3026.2023.04.010

Abstract ( 561 )

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In this paper， frequency is regarded as a new characteristic parameter to analyze vibration features. Firstly， the principle of vibration signal feature extraction was proposed， and the characteristic frequency function was obtained through the vibration feature extraction test of quick-point grinding. Then， the influence of different levels of technological parameters on grinding vibration under the machining or idle condition was analyzed. And the variation law of characteristic frequency was analyzed by comparing the contact and energy transfer relationship between the grinding wheel and workpiece. The results showed that the machining characteristic frequency is always smaller than the idle and the relative deviation of characteristic frequency decreases with the increase of the grinding wheel’s linear velocity， and increases with the increase of grinding depth and feed velocity. At the same time， the influence weight of each technological parameter on the characteristic frequency was compared， and the idea of improving the machining efficiency was put forward.

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Experimental Study on the Microstructure of FeCoNiCr High-Entropy Alloys by Selective Laser Melting

WEN Xue-long， WANG Cheng-bao， LIU Wen-bo， REN Hai-yang

2023, 44 (4): 536-543. DOI: 10.12068/j.issn.1005-3026.2023.04.011

Abstract ( 746 )

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The thermal analysis theory of selective laser melting was introduced， and FeCoNiCrAl_0.5 and FeCoNiCrAl_0.8 high-entropy alloys were prepared by selective laser melting. The effects of powder particle size， element content and process parameters on the microstructure of high-entropy alloys by selective laser melting were analyzed. The results showed that with the increase of laser power， the proportion of equiaxed crystals at the top of the specimen becomes smaller， while the proportion of dendrites in the bottom of the specimen becomes larger and larger. With the increase of scanning speed， the size and width of dendrite in the bottom of high-entropy alloy specimens decrease gradually. The effect of lap ratio on the microstructure of high-entropy alloys is small. It was found that the high-entropy alloy specimens have some defects such as cracks， dents and pores.

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Reliability Analysis of Rock Block Stability and Support for Underground Water-Sealed Storage Caverns

QIAO Li-ping， LU Wei-li， MIN Zhong-shun， WANG Zhe-chao

2023, 44 (4): 544-550. DOI: 10.12068/j.issn.1005-3026.2023.04.012

Abstract ( 552 )

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The stochastic distribution of geometrical and mechanical parameters of rock joints causes a high degree of uncertainty in the stability of rock mass engineering. Taking a project of underground water-sealed storage caverns as an example， and considering the uncertainty of dip directions， dip angles， cohesion and friction angles， the reliability of surrounding rock block stability and support system are studied using the reliability theory and numerical simulation， and the support parameters are tested and optimized. The results show that the reliability indexes of the surrounding rock blocks of Grade Ⅰ to IV are 4.23， 1.68， 0.65 and -0.07， respectively. After the support system is applied to Grade II， III and IV surrounding rocks， the reliability indexes of the surrounding rock blocks are 3.3， 3.0 and 2.0， respectively. The row spacing between supports is optimized， and the recommended values are 2.8， 2.0 and 1.6m for the surrounding rock blocks of Grade II， III and IV， respectively.

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Seepage Model of Water-Filled Goaf Based on Fluid-Solid Interaction

SHA Cheng-man， WANG Xing， YANG Hui-min

2023, 44 (4): 551-557. DOI: 10.12068/j.issn.1005-3026.2023.04.013

Abstract ( 517 )

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In order to study the influence of the rise and fall of the water table on the permeability coefficients of the water-filled goaf， the equivalent permeability coefficients in three main permeability directions with strain as parameters were derived according to the cubic law. FISH function was used to improve the unsaturated seepage calculation function of FLAC^3D based on the fluid-solid coupling calculation model， and the unsaturated element of the equivalent continuous medium fluid-solid coupling model of mining rock mass was modified to realize the simulation calculation of the seepage field and stress field of water-filled goaf. The influence of the seepage field on the stress field was reflected by the absolute value of the difference between principal permeability coefficient ratio and 1. By comparing the calculation results of pillar central unit before and after model modification， it could be seen that: the value increases with the rise of the water table. The effect of seepage field on stress field before model modification is greater than that after model modification. After model modification， the maximum and minimum principal strain curves show an inflection point when the saturation is 1. Since the parameters of the seepage model before modification are the same as those of saturated seepage， it can be verified that the modified model is more consistent with the unsaturated seepage theory. Finally， by comparing the data of the groundwater seepage flow in actual working conditions， the modified model is verified to be more consistent with the reality.

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Electrical Response Characteristics of High Temperature Damaged Sandstones Under Uniaxial Compression

JIA Peng， LI Bo， ZHU Peng-cheng， WANG Qi-wei

2023, 44 (4): 558-564. DOI: 10.12068/j.issn.1005-3026.2023.04.014

Abstract ( 528 )

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In order to study the electrical response characteristics of sandstones after high temperature， uniaxial compression tests were carried out on green sandstone samples at room temperature and heated at 200， 400， 500， 600 and 800℃， and the change law of resistivity during compression was monitored in real time. The results showed that corresponding to the compaction stage， stable crack growth stage， rapid crack growth stage and failure stage of rocks under uniaxial compression， the resistivity change of water-cooled high temperature sandstones shows four stages:small increase， steady increase， significant increase and sharp decrease of resistivity. When the heating temperature is lower than 400℃， the resistivity changing rate in the initial compaction state is under 10%， while when the heating temperature is over 400℃， the changing rate of resistivity increases and can be up to 50% when the heating temperature is 800℃. This indicates that the changing rate of resistivity can reflect the incipient damage degree in rocks. When the compressive pressure reaches 80%~90% of the peak strength， the changing rate of resistivity reaches its peak value， and then decreases sharply， which can be used as a precursor of rock failure. The anisotropic characteristics of resistivity change can indicate the location of the penetrated crack in such a way that the most significant change of resistivity can be observed near the upcoming penetrated crack.

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Stress Change Characteristics of the Existing Tunnel Surrounding Rocks by In-situ Expansion

SUN Da-zeng， ZHAO Wen， WANG Xin， BAI Qian

2023, 44 (4): 565-572. DOI: 10.12068/j.issn.1005-3026.2023.04.015

Abstract ( 560 )

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In order to evaluate the stress disturbance degree and redistribution characteristics of the expansion and excavation of existing tunnels， taking the in-situ expansion project of the Nanling single-track railway tunnel as the research background， based on the classical elastic-plastic theory， and combined with the Mohr-Coulomb yield criterion， the calculation formulas of the surrounding rock diameter and circumferential stress change during the expansion process were deduced， and the influences of different formation conditions， initial stress， and equal-circle calculation methods on stress change were analyzed. The results showed that the second excavation causes the radial stress to decrease in varying degrees compared with that before the expansion， and the circumferential stress first decreases and then increases， and finally remains in the original stress state; the surrounding rock stress distribution state is closely related to the surrounding rock conditions， initial stress， equal-circle calculation methods， and the simplified calculation method of the equal-circle calculation of the sum of 1/4 height and span has good applicability to the calculation of the stress change of the surrounding rocks for the in-situ expansion of a single-line tunnel. The on-site measurement has verified the accuracy of the calculation formula of stress change， and provided a theoretical basis for the design of the excavation scheme of expansion tunnels and the optimization of the support parameters.

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Study on Flotation of Ilmenite Based on High-Intensity Conditioning Process

YU Li， MENG Qing-you， YUAN Zhi-tao， XU Xin-yang

2023, 44 (4): 573-580. DOI: 10.12068/j.issn.1005-3026.2023.04.016

Abstract ( 607 )

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The effect of high-intensity conditioning on the flotation of ilmenite was systematically studied via flotation experiment， turbidity experiment and SEM-EDS. Ore samples are derived from the concentrate of high-intensity magnetic separation in the Panzhihua titanium processing plant. It was found that with the addition of collector， hetero-aggregation was tend to occur between hydrophobized ilmenite and titanaugite particles. Fine titanaugite particles could adhere to the surface of ilmenite and enter into the concentrate products， resulting in the non-selective flotation of titanaugite. After the treatment of high-intensity conditioning， the TiO₂ grade of concentrate increased sharply from 39.97% to 43.79%， while the recovery rate increased from 78.09% to 79.28%. The fluid force field generated by high-intensity conditioning can eliminate the hetero-aggregation between ilmenite and ilmenite particles and strengthen the dispersion state between them. This is the intrinsic reason for high-intensity conditioning to enhance the TiO₂ grade of titanium concentrate.

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Performance Degradation Law of Concretes in the Multi-salt Coupling Corrosion Environment

HE Sheng， QIN Zhi-di， LI Yu-tao5， YU Peng

2023, 44 (4): 581-589. DOI: 10.12068/j.issn.1005-3026.2023.04.017

Abstract ( 521 )

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In order to explore the effect of the actual industrial chemical corrosion environment on the physical and mechanical properties of concretes， the site exposure tests of half immersion and full immersion were adopted in the chlorine， sulfate and magnesium salt environments， and therewith the corresponding corrosion simulation tests were carried out in the laboratory. The effects of different water-binder ratios， different corrosion concentrations and different dry-wet periods on concretes’ quality， compressive strength， dynamic elastic modulus and thickness of the damaged layer were studied. The results showed that the relative mass， relative dynamic elastic modulus and compressive strength of half-immersed concretes and laboratory simulated concretes all increase first and then decrease with time and the thickness of the damaged layer continues to increase with time. The degradation damage of full-immersed concretes is much lower than those by half immersion， and the time required for each turning point by full immersion is prolonged. With the increase of the water-binder ratio， concentration， and shortening of the dry-wet period， it is easier to produce Friedel’s salt， ettringite， and magnesium hydroxide in concretes， and accelerate the deterioration of concretes. The order of corrosive ions infiltrating into concretes is:chloride ions， sulfate ions and magnesium ions.

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Impacts of Supervisor， Coworker， and Customer Workplace Incivility on Employees’ Work Outcomes

ZHANG Lan-xia， ZHAO Song-yan， WANG Le-le， QIAN Jin-hua

2023, 44 (4): 590-598. DOI: 10.12068/j.issn.1005-3026.2023.04.018

Abstract ( 629 )

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In light of affective events theory， and based on 457 matched samples and SEM(structural equation modeling) latent variable product indicator approach， the impacts of supervisor， coworker， and customer workplace incivility on task performance and counterproductive work behavior are discussed， and the mediating effect of negative emotion and the moderating effect of resilience are verified. The results show that supervisor and customer incivility negatively impact task performance; supervisor， coworker， and customer incivility positively impact counterproductive work behavior， and customer incivility has a stronger impact; negative emotion mediates the relationships between supervisor， coworker， and customer incivility and task performance and counterproductive work behavior; resilience weakens the positive impact of coworker incivility on negative emotion. This not only enriches the theoretical system of workplace incivility， but also provides references for organizations to effectively curb workplace incivility.

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Analysis of the Spatial Scale Structure and Influencing Factors of China’s Interprovincial Technology Transfer

PAN Xiong-feng， WANG Meng-yang

2023, 44 (4): 599-608. DOI: 10.12068/j.issn.1005-3026.2023.04.019

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Regarding the unbalanced development of Chinas provincial technology markets， using the contract value of the technology markets from 2006 to 2018 as the research data， the spatial scale structure changes， development trends and influencing factors of Chinas technology transfer sources and sinks are analyzed. The results show that the spatial scale and structure changes of Chinas technology transfer sources and sinks are in conformity with the monofractal Zipf distribution， and the distribution of technology transfer sources is relatively concentrated. The development trend of technology output and inflow in most provinces is different， and the changes in the sequence of the technology sinks are more volatile than the changes in the sources. Patents， R&D investment and R&D personnel will have a positive effect on regional technology output， and the improvement of regional economic development level， industrial structure， and fixed asset investment will attract more technology inflow.

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