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.

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.

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。

四川广电构建运维资料快速查询助手的探索

本文介绍了中国广电四川网络股份有限公司对运维资料快速查询助手的研发探索。同时,为进一步优化模型性能,本文结合大模型的微调方法,提出生成新的模型Qwen-lizehua:14B,其在运维资料快速查询助手中的应用极大地提升了问题解答的准确性和响应速度,从而为运维团队提供了强大且高效的技术支持。

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。

“嵌入式教学”在休闲体育专业教学改革中的应用与探索——基于成都体育学院休闲体育专业建设的实证研究

从嵌入性视角出发,对目前教学中存在的"教""学""实践"分离等问题进行分析。提出嵌入式教学服务在教学中的可行性,分析成都体育学院休闲体育专业嵌入式教学模式构建与实践情况,指出论证嵌入式教学模式对教学质量提升与教学的可持续发展有着不可忽视的重要作用。

欠发达地区本地能力、社会嵌入与商业模式构建分析--基于武陵山片区的多案例研究

研究选取武陵山片区7家典型新创企业进行多案例分析,探索欠发达地区新创企业商业活动中本地能力、社会嵌入与商业模式构建三者之间的交互影响及作用机制。研究结果发现,欠发达地区情境下,本地能力的不同维度对新创企业商业模式构建的作用机理存在差异;社会嵌入的不同维度对新创企业商业模式构建的作用机理也存在差异;社会嵌入既直接影响企业商业模式构建,又在本地能力与商业模式构建之间发挥正向调节作用,而且这种调节作用主要基于企业与其他价值链主体之间的非正式连接发挥作用。研究揭示,欠发达地区独特情境下新创企业商业模式构建的微观影响机制,形成对现有BOP战略研究的有效补充和完善,丰富了商业模式构建的理论研究。

制度嵌入:民族传统村落旅游发展模式的演进逻辑

制度在旅游发展模式演进中起到至关重要的作用。学界目前对旅游发展模式现状及横向优劣比较的研究较多,而对模式是如何演进以及如何解释制度对模式的作用机理缺乏相应的研究。文章基于新经济社会学中制度嵌入性的分析框架,结合郎德苗寨的实践案例,对旅游发展模式的演进逻辑进行考察和阐释。内生文化诉求、资本利益博弈与制度嵌入调试共同推动村落旅游发展模式的动态演进和多元共存。正式制度和非正式制度共生演化,分别借助科层制、项目制和制度赋权的路径嵌入于民族传统村落,通过制度创新重构村落旅游发展模式。

基于创新人才网络嵌入的孵化器商业模式研究

对创新型人才的引进、开发与保持一直是国家人才、科技和社会经济发展战略的核心与重点。科技企业孵化器是科技成果转化、高新技术产业培育和创新型人才开发的重要载体和平台,但目前普遍面临入孵企业对服务质量要求不断提高、孵化器孵化能力相对不足和二次创业等问题。本文以创新人才网络嵌入的全新视角,审视科技企业孵化器的创新要素系统集成、知识流动与共享、风险防范与化解等创新网络孵化的运行机制,构建科技企业孵化器新的商业模式和发展路径,促进科技企业孵化器发展模式的创新。

从组织依附视角理解离职:映像理论、“展开”模型和工作嵌入理论的融合

许多学者致力于开发新理论来解释员工为什么留职和离职问题。本研究首先通过回顾映像理论、"展开"模型和工作嵌入理论,讨论它们之间的关联,为提出综合的依附理论打下了基础。进而将上述三个理论加以整合,形成了以映像理论为心理评价机制,以工作嵌入为制约离职的网络阻力,以"震撼"和负面态度为离职动因,以"展开"模型为离职路径和框架的,用以解释员工离职和留职的综合依附理论。最后进一步论述了嵌入的各因素在"展开"模型所描述离职的不同阶段和不同评价检验中的影响作用。