A novel binary effective medium model to describe the prepeak stressstrain relationship of combined bodies of rock-like material and rock

Combined bodies of rock-like material and rock are widely encountered in geotechnical engineering,such as tunnels and mines.The existing theoretical models describing the stress-strain relationship of a combined body lack a binary feature.Based on effective medium theory,this paper presents the governing equation of the“elastic modulus”for combined and single bodies under triaxial compressive tests.A binary effective medium model is then established.Based on the compressive experiment of concretegranite combined bodies,the feasibility of determining the stress threshold based on crack axial strain is discussed,and the model is verified.The model is further extended to coal-rock combined bodies of more diverse types,and the variation laws of the compressive mechanical parameters are then discussed.The results show that the fitting accuracy of the model with the experimental curves of the concretegranite combined bodies and various types of coal-rock combined bodies are over 95%.The crack axial strain method can replace the crack volumetric strain method,which clarifies the physical meanings of the model parameters.The variation laws of matrix parameters and crack parameters are discussed in depth and are expected to be more widely used in geotechnical engineering.

Theory of mind deficits in patients with esophageal cancer combined with depression

AIM:To characterize the two components of theory of mind(ToM) in patients with esophageal cancer combined with depression.METHODS:Sixty-five patients with esophageal cancer combined with depression(depressed group) and 62 normal controls(control group) were assessed using reading the mind in the eyes test,faux pas task,verbal fluency test,digit span test and WAIS IQ test.The depressed group was divided into two subgroups including psychotic depressed(PD) group(32 cases) and nonpsychotic depressed(NPD) group(33 cases).The clinical symptoms of patients were assessed using Beck depression inventory version Ⅱ and brief psychiatric reacting scale(BPRS).RESULTS:There was a significant difference between the depressed group and the control group on tasks involving ToM social perceptual components(mind reading:t = 7.39,P < 0.01) and tests involving ToM social cognitive components(faux pas questions:t = 13.75,P < 0.01),respectively.A significant difference was also found among the PD group,the NPD group and the control group on mind reading(F = 32.98,P < 0.01) and faux pas questions(χ 2 = 78.15,P < 0.01),respectively.The PD group and NPD group performed worse than normal group controls both on mind reading and faux pas questions(P < 0.05).The PD group performed significantly worse than the NPD group on tasks involving ToM(mind reading:F = 18.99,P < 0.01;faux pas questions:F = 36.01,P < 0.01).In the depressed group,there was a negative correlation between ToM performances and BPRS total score(mind reading:r =-0.35,P < 0.01;faux pas questions:r =-0.51,P < 0.01),and between ToM performances and hostile suspiciousness factor score(mind reading:r =-0.75,P < 0.01;faux pas questions:r =-0.73,P < 0.01),respectively.CONCLUSION:The two components of ToM are both impaired in patients with esophageal cancer combined with depression.This indicates that there may be an association between ToM deficits and psychotic symptoms in clinical depression.

Temporal evidence combination method for multi-sensor target recognition based on DS theory and IFS

In order to effectively deal with the conflict temporal evidences without affecting the sequential and dynamic characteristics in the multi-sensor target recognition(MSTR) system at the decision making level, this paper proposes a Dempster-Shafer(DS) theory and intuitionistic fuzzy set(IFS) based temporal evidence combination method(DSIFS-TECM). To realize the method,the relationship between DS theory and IFS is firstly analyzed. And then the intuitionistic fuzzy possibility degree of intuitionistic fuzzy value(IFPD-IFV) is defined, and a novel ranking method with isotonicity for IFV is proposed. Finally, a calculation method for relative reliability factor(RRF) is designed based on the proposed ranking method. As a proof of the method, numerical analysis and experimental simulation are performed. The results indicate DSIFS-TECM is capable of dealing with the conflict temporal evidences and sensitive to the changing of time. Furthermore, compared with the existing methods, DSIFS-TECM has stronger ability of anti-interference.

Optimization of combined endoreversible Carnot heat engines with different objectives

Taking the output power, thermal efficiency, and thermo-economic performance as the optimization objectives, we optimize the operation parameters of a thermodynamic system with combined endoreversible Carnot heat engines in this paper. The applicabilities of the entropy generation minimization and entransy theory to the optimizations are discussed. For the discussed cases, only the entransy loss coefficient is always agreeable to the optimization of thermal efficiency. The applicabilities of the other discussed concepts to the optimizations are conditional. Different concepts and principles are needed for different optimization objectives, and the optimization principles have their application preconditions. When the preconditions are not satisfied, the principles may be not applicable.

Reasonable location parameters of pick and nozzle in combined cutting system

The drum shearer and high pressure water jet combined cutting system is an effective technology to cut hard coal-rock, but one problem of the technology is the choice of pick and nozzle location parameters. In order to solve the problem, the process and mechanism of combined cutting arc studied and mining seepage catastrophe theory is used to construct the mathematic and physical model of combined cutting hard coal-rock. Based on the model and detailed analysis of combined cutting mechanism, the single pick and nozzle combined cutting test-bed is built to test the main pick and nozzle location parameters of drum shearer and water jet combined cutting system. Test results show that the best vertical distance between the pick-tip and nozzle center point is the sum of cutting thickness and proper target distance in the Y axial direction; the best horizontal distance is the length between pick-tip point and coal-rock surface bursting crack point in the X axial direction. The best incident angle of water jet should be the same as the bursting crack line＇s angle in theory, but considering other important factors comprehensively, it is more reasonable when the incident angle of water jet is 90°.

Insights into electrochemical nitrogen reduction reaction mechanisms:Combined effect of single transition-metal and boron atom

Developing single-atom catalysts(SACs) for electrochemical devices is a frontier in energy conversion.The comparison of stability,activity and selectivity between various single atoms is one of the main research focuses in SACs.However,the in-depth understanding of the role that the coordination atoms of single atom play in the catalytic process is lacking.Herein,we proposed a graphene-like boroncarbon-nitride(BCN) monolayer as the support of single metal atom.The electrocatalytic nitrogen reduction reaction(eNRR) performances of 3 d,4 d transition metal(TM) atoms embedded in defective BCN were systematically investigated by means of density functional theory(DFT) computations.Our study shows that the TM-to-N and B-to-N π-back bonding can contribute to the activation of N_(2).Importantly,a combined effect is revealed between single TM atom and boron atom on eNRR:TM atom enhances the nitrogen reduction process especially in facilitating the N_(2) adsorption and the NH3 desorption,while boron atom modulates the bonding strength of key intermediates by balancing the charged species.Furthermore,Nb@BN3 possesses the highest electrocata lytic activity with limiting potential of-0.49 V,and exhibits a high selectivity for nitrogen reduction reaction(NRR) to ammonia compared with hydrogen evolution reaction(HER).As such,this work can stimulate a research doorway for designing multi-active sites of the anchored single atoms and the innate atoms of substrate based on the mechanistic insights to guide future eNRR research.

Analytic elasticity solution of bi-modulus beams under combined loads

A unified stress function for bi-modulus beams is proposed based on its mechanic sense on the boundary of beams. Elasticity solutions of stress and displacement for bi-modulus beams under combined loads are derived. The example analysis shows that the maximum tensile stress using the same elastic modulus theory is underestimated if the tensile elastic modulus is larger than the compressive elastic modulus. Otherwise, the maximum compressive stress is underestimated. The maximum tensile stress using the material mechanics solution is underestimated when the tensile elastic modulus is larger than the compressive elastic modulus to a certain extent. The error of stress using the material mechanics theory decreases as the span-to-height ratio of beams increases, which is apparent when L/h ≤ 5. The error also varies with the distributed load patterns.

Buckling analysis of shear deformable composite conical shells reinforced by CNTs subjected to combined loading on the two-parameter elastic foundation

The main objective of this study is to investigate the buckling analysis of CCSs reinforced by CNTs subjected to combined loading of hydrostatic pressure and axial compression resting on the twoparameter elastic foundation(T-P-EF).It is one of the first attempts to derive the governing equations of the CCSs reinforced with CNTs,based on a generalized first-order shear deformation shell theory(FSDST)which includes shell-foundation interaction.By adopting the extended mixing rule,the effective material properties of CCSs reinforced by CNTs with linear distributions are approximated by introducing some efficiency parameters.Three carbon nanotube distribution in the matrix,i.e.uniform distribution(U)and V and X-types linear distribution are taken into account.The stability equations are solved by using the Galerkin procedure to determine the combined buckling loads(CBLs)of the structure selected here.The numerical illustrations cover CBLs characteristics of CCSs reinforced by CNTs in the presence of the T-P-EF.Finally,a parametric study is carried out to study the influences of the foundation parameters,the volume fraction of carbon nanotubes and the types of reinforcement on the CBLs.

Correcting the systematic error of the density functional theory calculation:the alternate combination approach of genetic algorithm and neural network

The alternate combinational approach of genetic algorithm and neural network （AGANN） has been presented to correct the systematic error of the density functional theory （DFT） calculation. It treats the DFT as a black box and models the error through external statistical information. As a demonstration, the ACANN method has been applied in the correction of the lattice energies from the DFT calculation for 72 metal halides and hydrides. Through the AGANN correction, the mean absolute value of the relative errors of the calculated lattice energies to the experimental values decreases from 4.93% to 1.20% in the testing set. For comparison, the neural network approach reduces the mean value to 2.56%. And for the common combinational approach of genetic algorithm and neural network, the value drops to 2.15%. The multiple linear regression method almost has no correction effect here.

Postbuckling of Imperfect Stiffened Cylindrical Shells Under Combined External Liquid Pressure and Axial Compression

posthuckling analysis is presented for the stilTened cylindrical shell of finite length subjected to combined loading of external liquid pressure and axial compression. The formulations are based on a boundary layer theory of shell buckling, which includes the effects of nonlinear prebuckling deformations, nonlinear large deflections in the postbuckling range and initial geometrical imperfections of the shell. The 'smeared stifl'cner' approach is adopted for the stiffencrs. In the analysis a singular perturbation technique is used (o determine the interactive buckling loads and the postbuckling paths. Numerical examples cover the performance of perfect and imperfect, stringer and ring stiffened cylindrical shells. Typical results arc presented in the dimcnsionless graphical form.

POSTBUCKLING OF IMPERFECT STIFFENED CYLINDRICAL SHELLS UNDER COMBINED EXTERNAL PRESSURE AND HEATING

A postbuckling analysis is presented for a stiffened cylindrical shell of finite length subjected to combined loading of external pressure and a uniform temperature rise. The formulations are based on a boundary layer theory of shell buckling, which includes the effects of nonlinear prebuckling deformations, nonlinear large deflections in the postbuckling range and initial geometrical imperfections of the shell. The 'smeared stiffener' approach is adopted for the stiffeners. The analysis uses a singular perturbation technique to determine the interactive buckling loads and the postbuckling equilibrium paths. Numerical examples cover the performances of perfect and imperfect, stringer and ring stiffened cylindrical shells. Typical results are presented in dimensionless graphical form.

基于治未病理论灸药同治对实体恶性肿瘤化疗患者骨髓抑制的预防作用

目的:基于治未病理论探讨灸药同治对实体恶性肿瘤化疗患者骨髓抑制的预防作用。方法:选取2019年1月至2022年1月于武汉科技大学附属武汉亚心总医院接受治疗的实体恶性肿瘤化疗患者120例作为研究对象,采用随机数字表法分为对照组和观察组,每组60例。对照组常规接受化疗,观察组化疗前连续3 d给予灸药同治(艾灸+加味八珍汤)。比较治疗前、化疗后7 d 2组患者中医证候积分、血常规[血红蛋白(Hb)、白细胞计数(WBC)、血小板计数(PLT)、中性粒细胞计数(NEUT)]、生命质量[卡诺夫斯凯计分(KPS)、中国癌症患者生命质量(QOL_(2))调查问卷],比较化疗后7 d 2组患者骨髓抑制情况[发生率、严重程度、重组人粒细胞集落刺激因子(rhG-CSF)使用情况]。结果:化疗后7 d,2组患者中医证候积分升高,但观察组低于对照组(P<0.05);Hb、WBC、PLT、NEUT、KPS评分及QOL_(2)评分降低,但观察组高于对照组(均P<0.05);观察组骨髓抑制发生率、rhG-CSF使用率低于对照组,0、Ⅰ度比例高于对照组(均P<0.05)。结论:基于治未病理论,灸药同治能够改善实体恶性肿瘤化疗患者临床症状及血常规,提高患者生命质量,减少骨髓抑制的发生。

“植物生理学”理论结合实践的教学模式改革

“植物生理学”是高等农林院校植物生产类本科生的专业基础课,教学涉及的专业多,授课对象的知识结构和学习特点不断变化,且面临学时少、新知识和新技术层出不穷的窘境。因此,从甄选教学内容、丰富教学题材,改进教学方法,学以致用。建立“植物生理学”开放课堂,科研反哺教学、指导学生参加创新创业大赛、增强科研创新意识等方面对“植物生理学”进行了教学改革与实践。同时,“植物生理学”教学的研究对象选用本地的植物类型或地方品种并列举它们与当地生态环境之间的关系,使教学内容既贴近生活实际又符合学校的办学特色,既能提高学生的综合素质与实践能力,又可为培养创新型人才奠定基础。

基于组合赋权的压裂作业人因失误概率研究

压裂作业强度大,环境恶劣,长时间枯燥的作业容易诱发人因失误,造成事故,分析压裂现场人因可靠性对于提升压裂作业的安全和效率具有重要意义。在考虑压裂现场情境因素影响基础上,提出了一种组合赋权模糊人因可靠性分析方法,用以评估压裂现场人因失误概率。首先,通过对压裂现场的调研分析,结合压裂作业情境环境特点,基于认知可靠性与失误分析方法(CREAM)建立了适用于评估压裂作业的一级共同绩效条件CPC 8个,二级CPC因子评估指标36个。其次,根据实际工况中各CPC对人的绩效可靠性的影响程度不同,提出以差异系数法确定线性组合系数,基于序关系法与熵权法对各项评估指标进行主客观线性组合赋权。最后,利用本文方法分析四川某页岩气压裂作业现场人因失误概率,结果表明,较一般模糊CREAM方法,在不同情境环境下,随着情境环境水平的下降,组合赋权模糊CREAM方法对CPC评价数据敏感度更高,人因失误概率增加,并且变化速率加快,这与现场实际工况一致,为压裂现场的人因可靠性分析和人因失误概率量化结果优化提供了参考。

“大思政课”建设的理论意涵和实践进路

“大思政课”建设是推进思想政治理论课高质量发展的重要举措。“大思政课”区别于“大思政”,其本质属性是课程属性,通过各种方式实现教学中的理论与实际相结合,以达成育人目标;实践教学并非是“大思政课”的唯一实现途径,课堂讲授中史论结合的头脑思辨、社会资源和力量参与课堂教学过程、借助现代信息技术的虚拟现实教学场景体验等,也应是“大思政课”建设的重要举措。因此,应在教学论视域下明确“大思政课”建设的目标、内容、方式、主体及评价内涵,并在把准实践逻辑的基础上明晰其主要进路。

基于博弈论与改进CRITIC-AHP的配电网线路脆弱性评估

针对现有配电网线路脆弱性评估指标单一的问题,从配电网结构、运行状态和故障影响等三个方面出发,全面考虑网络拓扑结构、负荷类型、潮流分布、设备参数和线路故障等影响因素,提出了改进的线路介数、改进的线路度数、线路电压稳定性和线路潮流熵等脆弱性评估指标。为解决权重分配过程中出现的权重偏好问题,提出基于博弈论与改进CRITIC-AHP组合赋权法的综合评价模型。最后,通过在IEEE33节点系统上进行仿真,验证了所提方法的有效性。

高含水油田“二三结合”转换时机优化

针对现有转换时机研究方法无法满足高含水期老油田“二三结合”转换时机优化设计需要的问题,在综合分析三次采油转换时机和技术经济评价方法的基础上,考虑工程技术可行性和经济效益可行性,提出综合考虑技术、经济、社会价值的“二三结合”全生命周期开发价值链理念,建立高含水期老油田“二三结合”全生命周期效益稳产开发价值链模型,并实例分析“二三结合”转换时机对油藏最终采收率和生命周期的敏感性。结果表明,稳产、效益、生命周期是“二三结合”全生命周期效益稳产开发的主要考虑因素,转换时机对效益和稳产的影响是相对立的。

基于阴火理论的中西医结合免疫调节治疗展望

免疫治疗已成为当今医学解决重大疑难疾病的突破口之一,但其面临的挑战仍然不少。当前,中医学的阴火理论受到广泛关注,被应用于多种疾病的治疗中,其机制与调节机体的免疫状态密切相关。本文在系统回顾中医药免疫调节研究进展的基础上,以挖掘阴火理论的科学内涵为切入点,讨论阴火理论下指导中西医结合免疫治疗的可能性和新思路。多种中药单体、有效部位或者复方免疫促进、免疫抑制或者双向调节作用,在免疫调节中展现了巨大的潜力。阴火理论与免疫调节的关联密切,阴火的产生与免疫异常、慢性炎症、代谢异常、应激等密切相关,临床运用阴火理论治疗相关疾病能够有效调节免疫功能,降低炎症水平。阴火理论是深入传承中医药原创理论精华,有效对接西医免疫相关理论的范例,但仍需开展相关系统生物学研究,进一步升华中医药理论和实践经验,从而发挥中医药的特色优势,解决重大疑难疾病防治中的免疫失调难题,赋予生命科学新内涵,推动临床应用、验证和创新发展。

基于足迹理论的钢铁企业低碳选址评价方法

为推动钢铁企业在资源约束下完成产业升级,在环境约束下提升技术效率,提出一种基于足迹理论的钢铁企业低碳选址评价方法。首先,在钢铁企业常规选址指标的基础上,以足迹理论表征的环境支持力和压力指标为切入点,客观评估待选地区环境容量对新建厂址的容许程度,利用改进灰色关联度完成指标定量筛选,构建钢铁企业低碳选址评价体系。其次,运用差异系数法将主客观权重进行组合优化,采用可拓云模型求解选址综合评价等级隶属度和特征值,并结合可信度因子进行检验。最后,以某钢铁企业产能置换选址为例,确定待选厂址的评价等级。该方法在钢铁企业低碳选址综合评价中具有较好的可行性和适用性。

“数字信号处理”课程中的以渔易鱼

“数字信号处理”是信息类专业中的一门主干基础课,但在教学过程中,经常会遇到学生学习效果不佳、学习动力不足等问题。为了改善这些现状,结合五邑大学实际情况,从教学内容、教学方式、仿真实践等三个方面进行了改革探索,目的是通过理论与实际的结合改善该课程的学习现状,强调知识点的掌握,更重视培养学生的工科学习思维。期望通过以渔易鱼的方式,拓宽学生的工程视野,提高学生的学习兴趣,培养工程的思维方式。