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p-s平面上不同应力路径的非饱和土力学特性研究

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岩石力学与工程学报 2011年第7期30卷 1496-1501页

作者：苗强强陈正汉朱青青后勤工程学院建筑工程系重庆401331 西北民族大学化工学院甘肃兰州730000

通过7个吸力和净平均应力同时变化的非饱和含黏砂土固结试验,研究7条不同应力路径的试验在p-s-v,p-s-εv,p-s-εw和p-s-w空间曲线形状随角度α(净平均应力和吸力夹角)的变化规律,分析引起变化的机制,指出净平均应力是决定体变的重要因素... 详细信息

通过7个吸力和净平均应力同时变化的非饱和含黏砂土固结试验,研究7条不同应力路径的试验在p-s-v,p-s-εv,p-s-εw和p-s-w空间曲线形状随角度α(净平均应力和吸力夹角)的变化规律,分析引起变化的机制,指出净平均应力是决定体变的重要因素,吸力是决定水分变化的首要条件。并探讨p-s平面上7条应力路径屈服点连线轨迹的统一表达式,建立p-s平面上屈服点连线的统一抛物线表达式。最后运用该公式预测已有的试验数据,预测结果较为理想,说明该式预测p-s平面上不同应力路径各屈服点变化规律是较为可靠的。

关键词：土力学应力路径非饱和土吸力净平均应力

How can technology and efficiency alleviate the dilemma of economic growth and carbon emissions in China's industrial economy? A metafrontier decoupling decomposition analysis

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Petroleum Science 2024年第2期21卷 1415-1428页

作者： miao Wang Chao Feng School of Business Zhengzhou UniversityZhengzhou450001HenanChina School of Economics and Business Administration Chongqing UniversityChongqing400030China

This paper attempts to explore the decoupling relationship and its drivers between industrial economic increase and energy-related CO_(2) emissions(ICE). Firstly, the decoupling relationship was evaluated by Tapio index. Then, based on the DEA meta-frontier theory framework which taking into account the regional and industrial heterogeneity and index decomposition method, the driving factors of decoupling process were explored mainly from the view of technology and efficiency. The results show that during2000-2019, weak decoupling was the primary state. Investment scale expansion was the largest reason hindering decoupling process of industrial increase from ICE. Both energy saving and production technology achieved significant progress, which facilitated the decoupling process. Simultaneously, the energy technology gap and production technology gap among regions have been narrowed, and played a role in promoting decoupling process. On the contrary, both scale economy efficiency and pure technical efficiency have inhibiting effects on decoupling process. The former indicates that the scale economy of China's industry was not conducive to improve energy efficiency and production efficiency, while the latter indicates that resource misallocation problem may exist in both energy market and product market.

关键词： China's industrial sector Decoupling process Meta-frontier DEA Index decomposition method Driving factors

User Churn Prediction Hierarchical Model Based on Graph Attention Convolutional Neural Networks

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China Communications 2024年第7期21卷 169-185页

作者： Mei miao Tang miao Zhou Long School of Economics and Management Beijing Jiaotong UniversityBeijing 100044China School of Automotive and Rail Transit Nanjing Institute of TechnologyNanjing 211167China Nanjing Intelligent Aviation Research Institute Co. LtdNanjing 210014China

The telecommunications industry is becoming increasingly aware of potential subscriber churn as a result of the growing popularity of smartphones in the mobile Internet era,the quick development of telecommunications services,the implementation of the number portability policy,and the intensifying competition among *** the same time,users'consumption preferences and choices are *** churn prediction models must be created in order to accurately predict the churn tendency,since keeping existing customers is far less expensive than acquiring new *** conventional or learning-based algorithms can only go so far into a single subscriber's data;they cannot take into consideration changes in a subscriber's subscription and ignore the coupling and correlation between various ***,the current churn prediction models have a high computational burden,a fuzzy weight distribution,and significant resource economic *** prediction algorithms involving network models currently in use primarily take into account the private information shared between users with text and pictures,ignoring the reference value supplied by other users with the same *** work suggests a user churn prediction model based on Graph Attention Convolutional Neural Network(GAT-CNN)to address the aforementioned *** main contributions of this paper are as follows:Firstly,we present a three-tiered hierarchical cloud-edge cooperative framework that increases the volume of user feature input by means of two aggregations at the device,edge,and cloud ***,we extend the use of users'own data by introducing self-attention and graph convolution models to track the relative changes of both users and packages ***,we build an integrated offline-online system for churn prediction based on the strengths of the two models,and we experimentally validate the efficacy of cloudside collaborative training and *** summary,the churn

关键词： cloud-edge cooperative framework GAT-CNN self-attention and graph convolution models subscriber churn prediction

Dynamic plugging regulating strategy of pipeline robot based on reinforcement learning

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Petroleum Science 2024年第1期21卷 597-608页

作者： Xing-Yuan miao Hong Zhao College of Mechanical and Transportation Engineering China University of PetroleumBeijing102249China

Pipeline isolation plugging robot (PIPR) is an important tool in pipeline maintenance operation. During the plugging process, the violent vibration will occur by the flow field, which can cause serious damage to the pipeline and PIPR. In this paper, we propose a dynamic regulating strategy to reduce the plugging-induced vibration by regulating the spoiler angle and plugging velocity. Firstly, the dynamic plugging simulation and experiment are performed to study the flow field changes during dynamic plugging. And the pressure difference is proposed to evaluate the degree of flow field vibration. Secondly, the mathematical models of pressure difference with plugging states and spoiler angles are established based on the extreme learning machine (ELM) optimized by improved sparrow search algorithm (ISSA). Finally, a modified Q-learning algorithm based on simulated annealing is applied to determine the optimal strategy for the spoiler angle and plugging velocity in real time. The results show that the proposed method can reduce the plugging-induced vibration by 19.9% and 32.7% on average, compared with single-regulating methods. This study can effectively ensure the stability of the plugging process.

关键词： Pipeline isolation plugging robot Plugging-induced vibration Dynamic regulating strategy Extreme learning machine Improved sparrow search algorithm Modified Q-learning algorithm

How variable progenitor clones construct a largely invariant neocortex

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National Science Review 2024年第1期11卷 129-144页

作者： Zhongfu Shen Jiajun Yang qiangqiang Zhang Kuiyu Wang Xiaohui Lv Xiaolin Hu Jian Ma Song-Hai Shi New Cornerstone Science Laboratory IDG/McG overn Institute for Brain Research Tsinghua-Peking Center for Life Sciences Beijing Frontier Research Center for Biological Structure School of Life Sciences Tsinghua University Department of Computer Sciences Tsinghua University College of Life Sciences Nankai University Chinese Institute for Brain Research

The neocortex contains a vast collection of diverse neurons organized into distinct layers. While nearly all neocortical neurons are generated by radial glial progenitors(RGPs), it remains largely unclear how a complex yet organized neocortex is constructed reliably and robustly. Here, we show that the division behavior and neuronal output of RGPs are highly constrained with patterned variabilities to support the reliable and robust construction of the mouse neocortex. The neurogenic process of RGPs can be well-approximated by a consistent Poisson-like process unfolding over time, producing deep to superficial layer neurons progressively. The exact neuronal outputs regarding layer occupation are variable; yet, this variability is constrained systematically to support all layer formation, largely reflecting the variable intermediate progenitor generation and RGP neurogenic entry and exit timing differences. Together, these results define the fundamental features of neocortical neurogenesis with a balanced reliability and variability for the construction of the complex neocortex.

关键词： neocortex radial glial progenitor intermediate progenitor neurogenesis clonal variability layer formation

Synchronous deprotonation–protonation for mechanically robust chitin/aramid nanofibers conductive aerogel with excellent pressure sensing, thermal management, and electromagnetic interference shielding

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Nano Research 2024年第3期17卷 2038-2049页

作者： Xinxin Zhang Kunpeng Qian Jianhui Fang Sineenat Thaiboonrod miao miao Xin Feng Department of Chemistry College of SciencesShanghai UniversityShanghai 200444China Research Center of Nano Science and Technology College of SciencesShanghai UniversityShanghai 200444China School of Materials Sciences and Engineering Shanghai UniversityShanghai 200444China National Nanotechnology Center(NANOTEC) National Science and Technology Development Agency(NSTDA)Thailand Science ParkPathum Thani 12120Thailand

Aerogels with regularly porous structure and uniformly distributed conductive networks have received extensive attention in wearable electronic sensors,electromagnetic shielding,and so ***,the poor mechanical properties of the emerging nanofibers-based aerogels are limited in practical *** this work,we developed a synchronous deprotonation–protonation method in the KOH/dimethyl sulfoxide(DMSO)system at room temperature for achieving chitin cross-linked aramid nanofibers(CANFs)rather than chitin nanofibers(ChNFs)and aramid nanofibers(ANFs)separately by using chitin and aramid pulp as raw *** freeze-drying process,the cross-linked chitin/aramid nanofibers(CA)aerogel exhibited the synergetic properties of ChNF and ANF by the dual-nanofiber compensation *** mechanical stress of CA aerogel was 170 kPa at 80%compressive strain,increased by 750%compared with pure ChNF ***,the compressibility of CA aerogel was somewhat improved compared to ANF *** enhancement verified that the crosslinking reaction between ANF and ChNF during the synchronous deprotonation process was ***,the conductive aerogels with uniform porous structure(CA-M)were successfully obtained by vacuum impregnating CA aerogels in Ti_(3)C_(2)T_(x) MXene solution,displaying low thermal conductivity(0.01 W/(m·K)),high electromagnetic interference(EMI)shielding effectiveness(SE)(75 dB),flame retardant,and heat ***,the as-obtained CA-M aerogels were also applied as a pressure sensor with excellent compression cycle stability and superior human motion monitoring *** a result,the dual-nanofiber based conductive aerogels have great potentials in flexible/wearable electronics,EMI shielding,flame retardant,and heat insulation.

关键词： synchronous deprotonation–protonation electromagnetic interference(EMI)shielding flame retardant heat insulation pressure sensing

An attention graph stacked autoencoder for anomaly detection of electro-mechanical actuator using spatio-temporal multivariate signals

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Chinese Journal of Aeronautics 2024年第9期37卷 506-520页

作者： Jianyu WANG Heng ZHANG Qiang miao College of Electrical Engineering Sichuan UniversityChengdu 610065China

Health monitoring of electro-mechanical actuator(EMA)is critical to ensure the security of *** is difficult or even impossible to collect enough labeled failure or degradation data from actual *** autoencoder based on reconstruction loss is a popular model that can carry out anomaly detection with only consideration of normal training data,while it fails to capture spatio-temporal information from multivariate time series signals of multiple monitoring *** mine the spatio-temporal information from multivariate time series signals,this paper proposes an attention graph stacked autoencoder for EMA anomaly ***,attention graph con-volution is introduced into autoencoder to convolve temporal information from neighbor features to current features based on different weight ***,stacked autoencoder is applied to mine spatial information from those new aggregated temporal ***,based on the bench-mark reconstruction loss of normal training data,different health thresholds calculated by several statistic indicators can carry out anomaly detection for new testing *** comparison with tra-ditional stacked autoencoder,the proposed model could obtain higher fault detection rate and lower false alarm rate in EMA anomaly detection experiment.

关键词： Anomaly detection Spatio-temporal informa-tion Multivariate time series signals Attention graph convolution Stacked autoencoder

Effect of dissolved-oxygen on the flotation behavior of pyrite at high altitude area

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International Journal of Minerals,Metallurgy and Materials 2024年第10期31卷 2148-2158页

作者： Yan miao Guangke Ye Guofan Zhang School of Minerals Processing and Bio-engineering Central South UniversityChangsha 410083China

With the continuous development of mineral resources to high altitude areas,the study of sulfide ore flotation in unconventional systems has been *** is a consensus that moderate oxidation of sulfide ore is beneficial to flotation,but the specific suitable dissolved oxygen value is inconclusive,and there are few studies on sulfide ore flotation under low dissolved oxygen environment at high *** this paper,we designed and assembled an atmosphere simulation flotation equipment to simulate the flotation of pyrite at high altitude by controlling the partial pressure of N_(2)/O_(2) and dissolved oxygen under atmospheric conditions.X-ray photoelectron spec-troscopy(XPS),atomic force microscope(AFM),Fourier transform infrared spectrometer(FT-IR),UV-vis spectrophotometer,zeta po-tential,and contact angle measurements were used to reveal the effects of surface oxidation and agent adsorption on pyrite at high altitude(4600 m dissolved oxygen(DO)=4.0 mg/L).The results of pure mineral flotation indicated that the high altitude and low dissolved oxy-gen environment is favorable for pyrite *** angle measurements and XPS analysis showed that the high altitude atmosphere nslows down the oxidation of pyrite surface,facilitates S_(n)^(2-)/S^(0) production and enhances surface *** calcula-tions and zeta potential analysis showed that the influence of atmosphere on the form of pyrite adsorption is small,and the different atmo-spheric conditions are consistent with dixanthogen electrochemical adsorption,with lower Zeta potential under high altitude atmosphere and significant potential shift after sodium isobutyl xanthate(SIBX)*** results of FT-IR,UV-vis,and AFM analysis showed that SIBX adsorbed more on the surface of pyrite under high altitude atmosphere and adsorbed on the surface in a mesh structure com-posed of column/*** results of the experimental study revealed the reasons for the easy flotation of sul

关键词： high altitude dissolved-oxygen pyrite flotation oxidation

Morphology of impact fragmentation distribution of single spherical and ellipsoidal particles in drop weight experiments

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Particuology 2024年第3期86卷 137-148页

作者： Qiuhua miao Peng Huang Wenchang Zhu School of Mechanical Engineering Southeast UniversityNanjing211189China

Particle shape is an important factor affecting the fragmentation distribution of the ore *** investigate the influence of particle shape on the morphological fragmentation distribution characteristics,the crushable ore particles are defined as prolate,oblate ellipsoid and spherical particles,which have different aspect ratios(AR)and sphericity(S).Based on the drop weight experiment,the influence of the net drop height on the macroscopic mechanical behavior and crushing distribution characteristics of the single spherical and ellipsoidal particles is *** results show that different peak-shifting characteristics exist during particle *** fragmentation distribution peak shifts left when the increased impact energy is eventually only enough to break medium-sized ***,it shifts right when impact energy is increased enough to break largest-sized ***,regardless of whether the net drop height changes,the maximum continuous fragmentation degree presents"M"-shaped characteristic with the increased *** with the ellipsoid particles,the single spherical particle is more difficult to be broken by impact,with wider equivalent particle fragmentation *** the increase of particle sphericity,the maximum continuous fragmentation degree of a single ellipsoid particle has an overall trend of initial increase and subsequent *** when particle sphericity is 0.9

关键词： Ellipsoid particles Fragmentation distribution Drop weight experiment Numerical simulation