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大跨径预应力混凝土连续梁桥施工监控技术研究

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价值工程 2025年第1期44卷 62-64页

作者：查李剑上海同济检测技术有限公司上海201900

桥梁结构理想的几何线形与合理的内力状态不仅与设计有关,而且还依赖于科学合理的施工方法。如何通过施工时的浇筑过程的控制以及结构标高调整来获得预先设计的应力状态和几何线形,是大跨桥梁施工中非常关键的问题。因此,在对大跨度预... 详细信息

桥梁结构理想的几何线形与合理的内力状态不仅与设计有关,而且还依赖于科学合理的施工方法。如何通过施工时的浇筑过程的控制以及结构标高调整来获得预先设计的应力状态和几何线形,是大跨桥梁施工中非常关键的问题。因此,在对大跨度预应力混凝土桥梁施工过程中,为了保障其施工质量及安全性,应采取必要的监控技术对其进行检测。本文以实际工程为例,对监控技术进行总结,为类似大跨度预应力混凝土桥梁施工监控提供借鉴作用。

关键词：预应力混凝土悬臂桥梁施工监控

HOMOMORPHISMS BETWEEN CHEVALLEY GROUPS OF TYPES C_nAND G_2 OVER FINITE FIELDS

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Chinese Annals of Mathematics,Series B 1997年第2期18卷 167-172页

作者： zha JIANGUO Department of Applied Mathematics Tongji UniversityShanghai 200092China

It is known that there exists an isogeny sort of Chevalley groups G (Σ, F) associated to any indecomposable root system Σ and any field F . In this paper the author determines all nontrivial homomorphisms from G(Σ, k) to G(Σ, K) when the root system Σ is of type C n or G 2 , and the fields k and K are finite fields of characteristic p .

关键词： Chevalley group Homomorphism Finite field

基于机器学习筛选猪活体肌内脂肪含量间接选育和构建预测模型的关键性状

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南京农业大学学报 2025年第1期48卷 161-170页

作者：吴建杨文孟孜查成万吴望军南京农业大学动物科技学院江苏南京210095

[目的]本研究旨在探究猪断奶重、屠宰前活体重、背膘厚等性状因素对猪肌内脂肪(intramuscular fat,IMF)含量的影响,确定影响猪IMF含量的关键性状因素。[方法]以805头皮特兰×[杜洛克×(长白×大白)]四元商品猪群为试验对象,记录性别,测... 详细信息

[目的]本研究旨在探究猪断奶重、屠宰前活体重、背膘厚等性状因素对猪肌内脂肪(intramuscular fat,IMF)含量的影响,确定影响猪IMF含量的关键性状因素。[方法]以805头皮特兰×[杜洛克×(长白×大白)]四元商品猪群为试验对象,记录性别,测定初生重、断奶重、屠宰前活体重和IMF含量等14个性状,然后通过相关性分析从14个性状中初步筛选出影响IMF含量的性状因素,再通过随机森林模型评估各性状因素对IMF含量影响的重要性,进一步通过LASSO回归和逐步回归筛选出影响IMF含量的关键性状因素;在此基础上,利用广义线性模型(generalized linear model,GLM)分析关键性状因素不同水平对IMF含量的影响。[结果]相关性分析结果显示,猪IMF含量与断奶重(r=0.13, P0.05)。胸腰椎结合处背膘厚大于26 mm组的平均IMF含量(2.73%)显著高于其他背膘厚组(P0.05)。[结论]本研究通过机器学习确定了性别、断奶重、屠宰前活体重和胸腰椎结合处背膘厚4个与IMF含量显著相关的活体可测定性状,并发现平均IMF含量随着屠宰前活体重和胸腰椎结合处背膘厚的增加呈明显的上升趋势。

关键词：猪肌内脂肪间接选择模型构建机器学习活体可测定性状

Geometric Error Identification of Gantry-Type CNC Machine Tool Based on Multi-Station Synchronization Laser Tracers

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Chinese Journal of Mechanical Engineering 2024年第2期37卷 150-162页

作者： Jun zha Huijie zhang School of Mechanical Engineering Xi’an Jiaotong UniversityXi’an 710049China Xi’an Jiaotong University Suzhou Academy Suzhou 215123China

Laser tracers are a three-dimensional coordinate measurement system that are widely used in industrial *** propose a geometric error identification method based on multi-station synchronization laser tracers to enable the rapid and high-precision measurement of geometric errors for gantry-type computer numerical control(CNC)machine *** method also improves on the existing measurement efficiency issues in the single-base station measurement method and multi-base station time-sharing measurement *** consider a three-axis gantry-type CNC machine tool,and the geometric error mathematical model is derived and established based on the combination of screw theory and a topological analysis of the machine kinematic *** four-station laser tracers position and measurement points are realized based on the multi-point positioning principle.A self-calibration algorithm is proposed for the coordinate calibration process of a laser tracer using the Levenberg-Marquardt nonlinear least squares method,and the geometric error is solved using Taylor’s first-order linearization *** experimental results show that the geometric error calculated based on this modeling method is comparable to the results from the Etalon laser *** a volume of 800 mm×1000 mm×350 mm,the maximum differences of the linear,angular,and spatial position errors were 2.0μm,2.7μrad,and 12.0μm,respectively,which verifies the accuracy of the proposed *** research proposes a modeling method for the precise measurement of errors in machine tools,and the applied nature of this study also makes it relevant both to researchers and those in the industrial sector.

关键词： Multi-point positioning Multi-station synchronization CNC machine tool Geometric error Error separation

Evasion strategies of a three-player lifeline game

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Science China(Information Sciences) 2018年第11期61卷 144-154页

作者： Fan zhaNG Wenzhong zha School of Automation Beijing Institute of Technology State Key Laboratory of Intelligent Control and Decision of Complex System Information Science Academy China Electronics Technology Group Corporation

This study examines a multi-player pursuit-evasion game, more specifically, a three-player lifeline game in a planar environment, where a single evader is tasked with reaching a lifeline prior to capture. A decomposition method based on an explicit policy is proposed to address the game qualitatively from two main aspects:(1) the evader’s position distribution to guarantee winning the game(i.e., the escape zone),which is based on the premise of knowing the pursuers’ positions initially, and(2) evasion strategies in the escape zone. First, this study decomposes the three-player lifeline game into two two-player sub-games and obtains an analytic expression of the escape zone by constructing a barrier, which is an integration of the solutions of two sub-games. This study then explicitly partitions the escape zone into several regions and derives an evasion strategy for each region. In particular, this study provides a resultant force method for the evader to balance the active goal of reaching the lifeline and the passive goal of avoiding capture. Finally,some examples from a lifeline game involving more than one pursuer are used to verify the effectiveness and scalability of the evasion strategies.

关键词： lifeline game three-player pursuit-evasion game barrier evasion strategy game of kind

Adaptive learning algorithm based on mixture Gaussian background

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Journal of Systems Engineering and Electronics 2007年第2期18卷 369-376页

作者： zha Yufei Bi Duyan Signal and Information Processing Lab Engineering Coll. of Air Force Engineering Univ. Xi'an 710038 P. R. China

The key problem of the adaptive mixture background model is that the parameters can adaptively change according to the input data. To address the problem, a new method is proposed. Firstly, the recursive equations are inferred based on the maximum likelihood rule. Secondly, the forgetting factor and learning rate factor are redefined, and their still more general formulations are obtained by analyzing their practical functions. Lastly, the convergence of the proposed algorithm is proved to enable the estimation converge to a local maximum of the data likelihood function according to the stochastic approximation theory. The experiments show that the proposed learning algorithm excels the formers both in converging rate and accuracy.

关键词： Mixture Gaussian model Background model, Learning algorithm.

Heteroatom-doped porous carbon-supported single-atom catalysts for electrocatalytic energy conversion

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Journal of Energy Chemistry 2021年第12期30卷 54-73,I0002页

作者： Yue Shao Zhengtai zha Hong Wang Key Laboratory of Functional Polymer Materials Ministry of EducationInstitute of Polymer ChemistryCollege of ChemisttyNankai University.Tianjin 300071China

Electrocatalysts play a crucial role in the development of renewable energy conversion and storage *** unique advantages of heteroatom-doped porous carbon-supported single-atom electrocatalysts(SAC-HDPCs)are *** SAC-HDPCs exhibit outstanding activity,selectivity and stability due to their distinct electronic structure,satisfactory conductivity,controllable porosity and heteroatomdoping *** and significant developments involving the synthesis,characterization,and structure-property-function relationship of SAC-HDPCs have been made in recent *** this review,we describe recent research efforts involving advanced(in situ)characterization techniques,innovative synthetic strategies,and electrochemical energy conversion examples of *** electrocatalytic performance of SAC-HDPCs is further considered at an atomic level,and the mechanisms underlying this performance are also discussed in *** expect that these analyses and deductions will be useful for the design of new materials and may help to establish a foundation for the design of future SAC-HDPCs.

关键词： Carbon material Heteroatom doping Single-atom electrocatalyst Electrocatalytic energy conversion

Study on creep-fatigue damage evaluation for advanced 9%–12% chromium steels under stress controlled cycling

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Acta Metallurgica Sinica(English Letters) 2011年第2期24卷 148-154页

作者： Peng zha O Fuzhen XUAN Key Laboratory of Safety Science of Pressurized System Ministry of Education School of Mechanical andPower Engineering East China University of Science and Technology Shanghai 200237 China

Creep-fatigue interaction is one of the main damage mechanisms in high temperature plants and their components. Assessment of creep-fatigue properties is of practical importance for design and operation of high temperature components. However, the standard evaluation techniques, i.e. time fraction rule and ductility exhaustion one have limitations in accounting for the effects of control mode on the cyclic deformations. It was found that conventional linear cumulative damage rule failed in accurately evaluating the creep-fatigue life under stress controlled condition. The calculated creep damages by time fraction rule were excessively high, which led to overly conservative prediction of failure lives. In the present study, it was suggested that such over estimation of creep damage was mainly caused by anelastic strain upon stress loading. For precise assessment under conditions of stress control, a modified creep damage model accounting for the effect of anelastic creep was proposed. The assessments of creep fatigue data under stress controlled condition were performed with the new approach developed in this paper for a rotor material and a boiler material used in ultra supercritical power plants. It was shown that a more moderate amount of creep damage was obtained by the new model, which gave better predictions of failure life.

关键词： Creep-fatigue Creep damage 9%–12%Cr steels Stress control Time fraction rule

Probabilistic Controlled Teleportation of an Arbitrary Three-Qubit State

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Communications in Theoretical Physics 2008年第9期50卷 637-639页

作者： zha Xin-Wei Department of Applied Mathematics and Applied Physics Xi＇an Institute of Posts and Telecommunications Xi＇an 710121 China

Recently Jiang et al.[***.24 (2007) 1144] gave a scheme for probabilistic controlled tele-portation of a triplet W state from the sender Alice to the distant receiver *** m controlled qubits are sharedby m(s_1,s_2,...,s_m) spatially-separated *** on transformation operator,we can extend to teleporting anarbitrary three-qubit *** relation between the transformation operators and the Bob's unitary transformation isalso obtained.

关键词： controlled teleportation three-qubit state transformation operator