A p-version embedded model for simulation of concrete temperature fields with cooling pipes

Pipe cooling is an effective method of mass concrete temperature control, but its accurate and convenient numerical simulation is still a cumbersome problem. An improved embedded model, considering the water temperature variation along the pipe, was proposed for simulating the temperature field of early-age concrete structures containing cooling pipes. The improved model was verified with an engineering example. Then, the p-version self-adaption algorithm for the improved embedded model was deduced, and the initial values and boundary conditions were examined. Comparison of some numerical samples shows that the proposed model can provide satisfying precision and a higher efficiency. The analysis efficiency can be doubled at the same precision, even for a large-scale element. The p-version algorithm can fit grids of different sizes for the temperature field simulation. The convenience of the proposed algorithm lies in the possibility of locating more pipe segments in one element without the need of so regular a shape as in the explicit model.

Embedded model control:Reconciling modern control theory and error-based control design

The paper addresses the problem of reconciling the modern control paradigm developed by R. Kalman in the sixties of the past century, and the centenary error-based design of the proportional, integrative and derivative （PID） controllers. This is done with the help of the error loop whose stability is proved to be necessary and sufficient for the close-loop plant stability. The error loop is built by cascading the uncertain plant-to-model discrepancies （causal, parametric, initial state, neglected dynamics）, which are driven by the design model output and by arbitrary bounded signals, with the control unit transfer functions. The embedded model control takes advantage of the error loop and its equations to design appropriate algorithms of the modern control theory （state predictor, control law, reference generator）, which guarantee the error loop stability and performance. A simulated multivariate case study shows modeling and control design steps and the coherence of the predicted and simulated performance.

Study on a Dual Embedded Discrete Fracture Model for Fluid Flow in Fractured Porous Media

Simulation of fluid flow in the fractured porous media is very important and challenging.Researchers have developed some models for fractured porous media.With the development of related research in recent years,the prospect of embedded discrete fracture model(EDFM)is more and more bright.However,since the size of the fractures in the actual reservoir varies greatly,a very fine grid should be used which leads to a huge burden to the computing resources.To address this challenge,in the present paper,an upscaling based model is proposed.In this model,the flow in large-scale fractures is directly described by the EDFM while that in the small-scale fractures is upscaled through local simulation by EDFM.The EDFM is used to simulate the large-and small-scale fractures independently two times,so the new model is called dual embedded discrete fracture model(D-EDFM).In this paper,the detailed implementation process of D-EDFM is introduced and,through test cases,it is found the proposed model is a feasible method to simulate the flow in fractured porous media.

EFFECTIVE ELASTIC MODULI OF INHOMOGENEOUS SOLIDS BY EMBEDDED CELL MODEL

An embedded cell model is presented to obtain the effective elastic moduli for three-dimensional two-phase composites which is an exact analytic formula without any simplified approximation and can be expressed in an explicit form. For the different cells such as spherical inclusions and cracks surrounded by sphere and oblate ellipsoidal matrix, the effective elastic moduli are evaluated and the results are compared with those from various micromechanics models. These results show that the present model is direct, simple and efficient to deal with three-dimensional two-phase composites.

数字平台生态嵌入对商业模式创新的影响研究——基于资源编排理论的视角

数字平台生态系统是缓解企业资源与能力约束进而推动企业实现商业模式创新的重要载体,但数字平台生态嵌入如何影响商业模式创新尚未被充分揭示。基于资源编排理论,构建并检验了数字平台生态嵌入通过能力进化式重构与能力替代式重构作用于商业模式创新的双中介模型,并探讨了组织敏捷性的调节作用。研究发现:数字平台生态嵌入正向影响商业模式创新;能力进化式重构与能力替代式重构在数字平台生态嵌入与商业模式创新的关系中起双中介作用;组织敏捷性不仅会强化数字平台生态嵌入与能力进化式重构和能力替代式重构之间的正向关系,还会正向强化数字平台生态嵌入通过能力进化式重构与替代式重构影响商业模式创新的中介路径。研究结论丰富了商业模式创新的前因研究,并为企业嵌入数字平台生态系统进行商业模式创新提供了实践启示。

治理嵌入与经济增长要素效率——基于多层统计模型的分析

文章基于中国省际数据,对经济增长要素效率的治理嵌入影响进行了实证分析,结果表明:省际资本效率、劳动效率、人力资本效率和技术创新效率存在异质性;行政、市场和社会三种治理方式及其交互项通过显著影响基本驱动要素的效率间接影响经济增长。因此,在分析经济增长时,既要考虑基本驱动因素,也要考虑治理嵌入性因素对影响要素效率的作用,同时要根据各省之间影响的异质性和不同时期的趋势,围绕效率的提升设计政策体系,以实现高质量的经济增长。

基于嵌入性理论医养安宁疗护服务模式的构建

目的 基于嵌入性理论构建科学、规范的医养安宁疗护服务模式,旨在为医养结合背景下开展安宁疗护服务提供指导。方法 以嵌入性理论为指导,确定一级条目为制度嵌入、结构嵌入、认知嵌入和文化嵌入。通过文献研究和小组讨论初步拟定医养安宁疗护模式框架,采用德尔菲专家函询法,邀请15名安宁疗护、医养结合和老年专科等相关领域专家进行2轮专家函询。结果 两轮问卷回收率和有效率均为100.0%,专家权威系数均为0.930,肯德尔和谐系数分别为0.231和0.254(P<0.001),最终形成包括4个一级条目、8个二级条目、50个三级条目的医养安宁疗护服务模式。结论 基于嵌入性理论的医养安宁疗护服务模式具有较高的可靠性、科学性,可以提高临终老人的生活质量,为医养结合背景下的安宁疗护实践提供指导。

CO_(2)flooding in shale oil reservoir with radial borehole fracturing for CO_(2)storage and enhanced oil recovery

This study introduces a novel method integrating CO_(2)flooding with radial borehole fracturing for enhanced oil recovery and CO_(2)underground storage,a solution to the limited vertical stimulation reservoir volume in horizontal well fracturing.A numerical model is established to investigate the production rate,reservoir pressure field,and CO_(2)saturation distribution corresponding to changing time of CO_(2)flooding with radial borehole fracturing.A sensitivity analysis on the influence of CO_(2)injection location,layer spacing,pressure difference,borehole number,and hydraulic fractures on oil production and CO_(2)storage is conducted.The CO_(2)flooding process is divided into four stages.Reductions in layer spacing will significantly improve oil production rate and gas storage capacity.However,serious gas channeling can occur when the spacing is lower than 20 m.Increasing the pressure difference between the producer and injector,the borehole number,the hydraulic fracture height,and the fracture width can also increase the oil production rate and gas storage rate.Sensitivity analysis shows that layer spacing and fracture height greatly influence gas storage and oil production.Research outcomes are expected to provide a theoretical basis for the efficient development of shale oil reservoirs in the vertical direction.

High-Precision Flow Numerical Simulation and Productivity Evaluation of Shale Oil Considering Stress Sensitivity

Continental shale oil reservoirs,characterized by numerous bedding planes and micro-nano scale pores,feature significantly higher stress sensitivity compared to other types of reservoirs.However,research on suitable stress sensitivity characterization models is still limited.In this study,three commonly used stress sensitivity models for shale oil reservoirs were considered,and experiments on representative core samples were conducted.By fitting and comparing the data,the“exponential model”was identified as a characterization model that accurately represents stress sensitivity in continental shale oil reservoirs.To validate the accuracy of the model,a two-phase seepage mathematical model for shale oil reservoirs coupled with the exponential model was introduced.The model was discretely solved using the finite volume method,and its accuracy was verified through the commercial simulator CMG.The study evaluated the productivity of a typical horizontal well under different engineering,geological,and fracture conditions.The results indicate that considering stress sensitivity leads to a 13.57%reduction in production for the same matrix permeability.Additionally,as the fracture half-length and the number of fractures increase,and the bottomhole flowing pressure decreases,the reservoir stress sensitivity becomes higher.

资本下乡与农民进厂——双重嵌入性与S镇桑蚕产业发展

乡村振兴依赖产业发展。农村产业发展既需要符合政策目标,又需要适应乡土社会。在学理上需要从政治嵌入性和社会嵌入性角度去分析农村产业发展的具体机制。以中西部省份S镇桑蚕产业大规模经营及其用工模式为经验案例,研究讨论在双重嵌入性之下资本下乡和用工模式的实践特征。研究发现资本下乡需要大规模经营,这依赖地方政府推动大面积土地流转,从而在产业组织架构上依附于地方权力结构。在具体用工模式上资本依赖乡土关系,并通过乡土关系最大化实现在地化雇工,这亦是政策本身的目标。双重嵌入性是对资本的硬约束,降低其自主性。在这一过程中资本依然具有部分能动性,在农村产业发展过程中实现自身利益。

政府补贴、网络结构嵌入与企业技术创新——基于中国新能源汽车企业的实证研究

新能源汽车作为全球科技创新的前沿领域之一,为我国经济发展注入新动能。为进一步探索补贴政策对新能源汽车企业技术创新的影响机制,本研究以专利视角构建企业协作研发网络,从实质性创新与策略性创新两个维度,采用负二项回归分析政府补贴对企业技术创新的影响,并考察网络结构嵌入特征在其中的调节作用。结果表明:(1)政府补贴能够有效激励新能源汽车企业实质性创新。(2)随着网络结构嵌入程度的不断深化,政府补贴促进企业实质性创新的作用更为显著。本研究拓展了政府补贴与企业技术创新的理论研究,为企业管理者提升技术创新水平提供科学依据。

New advances in coal structure model

Although human beings have come to understand and utilize coal for a very long history, no theoretical breakthrough in the study of coal structure has been made, which still needs continuous efforts of coal chemical workers. Based on the viewpoint of ‘vague/clear', the species classification and accurate analysis on coal were conducted by using the natural clustering all-component separation method. A more systematic and detailed coal embedded structure model theory which is suitable for coal of all ranks was developed from the previous one and a more complete theoretical system about the component and structure of coal was constructed. The whole establishment process of the theory was summarized and some of the main support data and analysis test results, including TEM, AFM, FTIR, GC/MS, MALDI/TOF/MS, DART/MSD, fractal analysis and so on were provided. The coal embedded structure theory fully considers both the identity and the particularity of all-rank coal, reflects the coal component and structure in the full range of coal rank, solves the systematic cognitive problem of coal component and structure on macro and micro level, and provides a valuable and meaningful theoretical approach for the coal processing and conversion technology.

A smart productivity evaluation method for shale gas wells based on 3D fractal fracture network model

The generation method of three-dimensional fractal discrete fracture network(FDFN)based on multiplicative cascade process was developed.The complex multi-scale fracture system in shale after fracturing was characterized by coupling the artificial fracture model and the natural fracture model.Based on an assisted history matching(AHM)using multiple-proxy-based Markov chain Monte Carlo algorithm(MCMC),an embedded discrete fracture modeling(EDFM)incorporated with reservoir simulator was used to predict productivity of shale gas well.When using the natural fracture generation method,the distribution of natural fracture network can be controlled by fractal parameters,and the natural fracture network generated coupling with artificial fractures can characterize the complex system of different-scale fractures in shale after fracturing.The EDFM,with fewer grids and less computation time consumption,can characterize the attributes of natural fractures and artificial fractures flexibly,and simulate the details of mass transfer between matrix cells and fractures while reducing computation significantly.The combination of AMH and EDFM can lower the uncertainty of reservoir and fracture parameters,and realize effective inversion of key reservoir and fracture parameters and the productivity forecast of shale gas wells.Application demonstrates the results from the proposed productivity prediction model integrating FDFN,EDFM and AHM have high credibility.

Small-signal modeling of GaN HEMT switch with a new intrinsic elements extraction method

A novel and accurate method is proposed to extract the intrinsic elements of the GaN high-electron-mobility transistor（HEMT） switch.The new extraction method is verified by comparing the simulated S-parameters with the measured data over the 5-40 GHz frequency range.The percentage errors E（ij） within 3.83% show the great agreement between the simulated S-parameters and the measured data.

Well interference evaluation considering complex fracture networks through pressure and rate transient analysis in unconventional reservoirs

Severe well interference through complex fracture networks(CFNs)can be observed among multi-well pads in low permeability reservoirs.The well interference analysis between multi-fractured horizontal wells(MFHWs)is vitally important for reservoir effective development.Well interference has been historically investigated by pressure transient analysis,while it has shown that rate transient analysis has great potential in well interference diagnosis.However,the impact of complex fracture networks(CFNs)on rate transient behavior of parent well and child well in unconventional reservoirs is still not clear.To further investigate,this paper develops an integrated approach combining pressure and rate transient analysis for well interference diagnosis considering CFNs.To perform multi-well simulation considering CFNs,non-intrusive embedded discrete fracture model approach was applied for coupling fracture with reservoir models.The impact of CFN including natural fractures and frac-hits on pressure and rate transient behavior in multi-well system was investigated.On a logelog plot,interference flow and compound linear flow are two new flow regimes caused by nearby producers.When both NFs and frac-hits are present in the reservoir,frac-hits have a greater impact on well#1 which contains frac-hits,and NFs have greater impact on well#3 which does not have frac-hits.For all well producing circumstances,it might be challenging to see divergence during pseudosteady state flow brought on by frac-hits on the logelog plot.Besides,when NFs occur,reservoir depletion becomes noticeable in comparison to frac-hits in pressure distribution.Application of this integrated approach demonstrates that it works well to characterize the well interference among different multi-fractured horizontal wells in a well pad.Better reservoir evaluation can be acquired based on the new features observed in the novel model,demonstrating the practicability of the proposed approach.The findings of this study can help for better evaluating well interference degree in multi-well systems combing PTA and RTA,which can reduce the uncertainty and improve the accuracy of the well interference analysis based on both field pressure and rate data.

A Multi-Level Circulant Cross-Modal Transformer for Multimodal Speech Emotion Recognition

Speech emotion recognition,as an important component of humancomputer interaction technology,has received increasing attention.Recent studies have treated emotion recognition of speech signals as a multimodal task,due to its inclusion of the semantic features of two different modalities,i.e.,audio and text.However,existing methods often fail in effectively represent features and capture correlations.This paper presents a multi-level circulant cross-modal Transformer(MLCCT)formultimodal speech emotion recognition.The proposed model can be divided into three steps,feature extraction,interaction and fusion.Self-supervised embedding models are introduced for feature extraction,which give a more powerful representation of the original data than those using spectrograms or audio features such as Mel-frequency cepstral coefficients(MFCCs)and low-level descriptors(LLDs).In particular,MLCCT contains two types of feature interaction processes,where a bidirectional Long Short-term Memory(Bi-LSTM)with circulant interaction mechanism is proposed for low-level features,while a two-stream residual cross-modal Transformer block is appliedwhen high-level features are involved.Finally,we choose self-attention blocks for fusion and a fully connected layer to make predictions.To evaluate the performance of our proposed model,comprehensive experiments are conducted on three widely used benchmark datasets including IEMOCAP,MELD and CMU-MOSEI.The competitive results verify the effectiveness of our approach.

农户可降解地膜采用意愿的影响因素及层次结构分解——基于社会嵌入与现实情景的实证分析

为加快可降解地膜推广普及进度,利用江苏、山东两省563份使用地膜农户的调研数据,立足于社会嵌入理论与现实情景,借助二元Logistic模型和解释结构模型(ISM)探究了农户可降解地膜采用意愿的影响因素,并解释了显著影响因素间的逻辑关系与层次结构。分析表明:农户受教育程度、合作社成员身份等10个影响因素对农户可降解地膜采用意愿产生显著影响;其中受教育程度和制度信任为深层根源因素,合作社成员身份、政策宣传、补贴力度、试验示范为中层间接因素,生态价值认知、经济价值认知、带动效应、预期应用效果为表层直接因素;模型发生路径可概括为“三路径、单驱动”。今后,应进一步加大教育培训和宣传力度,完善现有补贴政策,加快可降解地膜研发迭代,不断激发农户可降解地膜采用意愿,促进农业绿色转型发展。

Analysis of fracture propagation and shale gas production by intensive volume fracturing

This paper presents an integrated study from fracture propagation modeling to gas flow modeling and a correlation analysis to explore the key controlling factors of intensive volume fracturing.The fracture propagation model takes into account the interaction between hydraulic fracture and natural fracture by means of the displacement discontinuity method(DDM)and the Picard iterative method.The shale gas flow considers multiple transport mechanisms,and the flow in the fracture network is handled by the embedded discrete fracture model(EDFM).A series of numerical simulations are conducted to analyze the effects of the cluster number,stage spacing,stress difference coefficient,and natural fracture distribution on the stimulated fracture area,fractal dimension,and cumulative gas production,and their correlation coefficients are obtained.The results show that the most influential factors to the stimulated fracture area are the stress difference ratio,stage spacing,and natural fracture density,while those to the cumulative gas production are the stress difference ratio,natural fracture density,and cluster number.This indicates that the stress condition dominates the gas production,and employing intensive volume fracturing(by properly increasing the cluster number)is beneficial for improving the final cumulative gas production.

嵌入性视角下社区嵌入式养老模式优化路径研究——基于西安市嵌入式养老服务实践的思考

目的:我国老龄化进程不断加快,高龄、失能失智老人的数量持续攀升,嵌入式养老模式是积极应对人口老龄化的关键之举。本研究基于嵌入性理论视角,在西安市社区嵌入式养老服务实践的基础上,探究社区嵌入式养老服务模式实践中的问题并提出优化路径。方法:通过文献梳理嵌入式养老的内涵与特征,利用调研结果和政府统计资料分析西安市嵌入式养老服务实践的特征与不足,依托嵌入性理论,识别问题并提出针对性建议。结果与结论:研究发现目前西安市社区嵌入式养老模式存在认知嵌入水平较低、政治嵌入待完善、文化嵌入不到位、结构嵌入不协调的问题,提出了提升社区嵌入式养老模式的知名度与美誉度、完善政府支持与监管体系、重视文化养老、探索多元主体合作范式、明确功能定位构建科学发展结构等优化建议。

Optimization of operational strategies for rich gas enhanced oil recovery based on a pilot test in the Bakken tight oil reservoir

Horizontal well drilling and multistage hydraulic fracturing have been demonstrated as effective approaches for stimulating oil production in the Bakken tight oil reservoir.However,after multiple years of production,primary oil recovery in the Bakken is generally less than 10%of the estimated original oil in place.Gas huff‘n’puff(HnP)has been tested in the Bakken Formation as an enhanced oil recovery(EOR)method;however,most field pilot test results showed no significant incremental oil production.One of the factors affecting HnP EOR performance is premature gas breakthrough,which is one of the most critical issues observed in the field because of the presence of interwell fractures.Consequently,injected gas rapidly reaches adjacent production wells without contacting reservoir rock and increasing oil recovery.Proper conformance control is therefore needed to avoid early gas breakthrough and improve EOR performance.In this study,a rich gas EOR pilot in the Bakken was carefully analyzed to collect the essential reservoir and operational data.A simulation model with 16 wells was then developed to reproduce the production history and predict the EOR performance with and without conformance control.EOR operational strategies,including single-and multiple-well HnP,with different gas injection constraints were investigated.The simulation results of single-well HnP without conformance control showed that a rich gas injection rate of at least 10 MMscfd was needed to yield meaningful incremental oil production.The strategy of conformance control via water injection could significantly improve oil production in the HnP well,but injecting an excessive amount of water also leads to water breakthrough and loss of oil production in the offset wells.By analyzing the production performance of the wells individually,the arrangement of wells was optimized for multiple-well HnP EOR.The multiwell results showed that rich gas EOR could improve oil production up to 7.4%by employing conformance control strategies.Furthermore,replacing rich gas with propane as the injection gas could result in 14%of incremental oil production.