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Deviation of light path in Born-Infeld type gravitational field 被引量:1
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作者 张可锋 黄增光 +1 位作者 方伟 陆惠卿 《Journal of Shanghai University(English Edition)》 CAS 2006年第6期497-499,共3页
The discovery of "twin quasi-stellar objects" arose interests among astronomers and astrophysicists to study gravitational leasing problem. Deviation of light from straight path is caused by the presence of massive ... The discovery of "twin quasi-stellar objects" arose interests among astronomers and astrophysicists to study gravitational leasing problem. Deviation of light from straight path is caused by the presence of massive objects, i.e., the presence of gravitational field according to the general theory of relativity. It is shown that the low energy effective field theory on D-branes is of the Born-Infeld type. In this work a Born-Infeld type gravitational field is pasttflated. An explicit representation of the angular deviation of light path is derived based on the space time metric in the Born-Infeld theory. 展开更多
关键词 Bom-Infeld theory Einstein's general relativity theory deviation of light path.
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Development of Dual-light Path Monitoring System of Optical Thin-film Thickness 被引量:4
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作者 许世军 《Defence Technology(防务技术)》 SCIE EI CAS 2005年第1期77-82,共6页
The accurate monitoring of optical thin-film thickness is a key technique for depositing optical thin-film. For existing coating equipments, which are low precision and automation level on monitoring thin-film thickne... The accurate monitoring of optical thin-film thickness is a key technique for depositing optical thin-film. For existing coating equipments, which are low precision and automation level on monitoring thin-film thickness, a new photoelectric control and analysis system has been developed. In the new system, main techniques include a photoelectric system with dual-light path, a dual-lock-phase circuit system and a comprehensive digital processing-control-analysis system.The test results of new system show that the static and dynamic stabilities and the control precision of thin-film thickness are extremely increased. The standard deviation of thin-film thickness, which indicates the duplication of thin-film thickness monitoring, is equal to or less than 0.72%. The display resolution limit on reflectivity is 0.02 %. In the system, the linearity of drift is very high, and the static drift ratio approaches zero. 展开更多
关键词 光学机械 薄膜厚度监控 稳定性 等光路径 生长工艺
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Variance Analysis and Adaptive Sampling for Indirect Light Path Reuse
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作者 Hao Qin Xin Sun +3 位作者 Jun Yan Qi-Ming Hou Zhong Ren Kun Zhou 《Journal of Computer Science & Technology》 SCIE EI CSCD 2016年第3期547-560,共14页
In this paper, we study the estimation variance of a set of global illumination algorithms based on indirect light path reuse. These algorithms usually contain two passes -- in the first pass, a small number of indire... In this paper, we study the estimation variance of a set of global illumination algorithms based on indirect light path reuse. These algorithms usually contain two passes -- in the first pass, a small number of indirect light samples are generated and evaluated, and they are then reused by a large number of reconstruction samples in the second pass. Our analysis shows that the covariance of the reconstruction samples dominates the estimation variance under high reconstruction rates and increasing the reconstruction rate cannot effectively reduce the covariance. We also find that the covariance represents to what degree the indirect light samples are reused during reconstruction. This analysis motivates us to design a heuristic approximating the covariance as well as an adaptive sampling scheme based on this heuristic to reduce the rendering variance. We validate our analysis and adaptive sampling scheme in the indirect light field reconstruction algorithm and the axis-aligned filtering algorithm for indirect lighting. Experiments are in accordance with our analysis and show that rendering artifacts can be greatly reduced at a similar computational cost. 展开更多
关键词 Monte Carlo method global illumination variance indirect light path reuse
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Light-Front Hamiltonian and Path Integral Formulations of the Conformally Gauge-Fixed Polyakov D1 Brane Action 被引量:1
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作者 Usha Kulshreshtha Daya Shankar Kulshreshtha 《Journal of Modern Physics》 2011年第5期335-340,共6页
In a recent paper we have studied the Hamiltonian and path integral quantizations of the conformally gauge-fixed Polyakov D1 brane action in the instant-form of dynamics using the equal world-sheet time framework on t... In a recent paper we have studied the Hamiltonian and path integral quantizations of the conformally gauge-fixed Polyakov D1 brane action in the instant-form of dynamics using the equal world-sheet time framework on the hyperplanes defined by the world- sheet time . In the present work we quantize the same theory in the equal light-cone world-sheet time framework, on the hyperplanes of the light-front defined by the light-cone world-sheet time , using the standard constraint quantization techniques in the Hamiltonian and path integral formulations. The light-front theory is seen to be a constrained system in the sense of Dirac, which is in contrast to the corresponding case of the instant-form theory, where the theory remains unconstrained in the sense of Dirac. The light-front theory is seen to possess a set of twenty six primary second-class contraints. In the present work Hamiltonian and path integral quantizations of this theory are studied on the light-front. 展开更多
关键词 light-FRONT QUANTIZATION HAMILTONIAN QUANTIZATION path Integral QUANTIZATION Constrained Dynamics Constraint QUANTIZATION GAUGE SYMMETRY STRING GAUGE SYMMETRY STRING Theory D-brane Actions Polyakov Action light-Cone Quantization.
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Light-Front Hamiltonian, Path Integral and BRST Formulations of the Chern-Simons-Higgs Theory in the Broken Symmetry Phase
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作者 Usha Kulshreshtha Daya S. Kulshreshtha James P. Vary 《Journal of Modern Physics》 2013年第4期38-48,共11页
In the present work we study the Hamiltonian, path integral and BRST formulations of the Chern-Simons-Higgs theory in two-space one-time dimensions, in the so-called broken symmetry phase of the Higgs potential (where... In the present work we study the Hamiltonian, path integral and BRST formulations of the Chern-Simons-Higgs theory in two-space one-time dimensions, in the so-called broken symmetry phase of the Higgs potential (where the phase φ(xμ) of the complex matter field Φ(xμ) carries the charge degree of freedom of the complex matter field and is akin to the Goldstone boson) on the light-front (i.e., on the hyperplanes defined by the fixed light-cone time). The theory is seen to possess a set of first-class constraints and the local vector gauge symmetry. The theory being gauge-invariant is quantized under appropriate gauge-fixing conditions. The explicit Hamiltonian and path integral quantization is achieved under the above light-cone gauges. The Heisenberg equations of motion of the system are derived for the physical degrees of freedom of the system. Finally the BRST quantization of the system is achieved under appropriate BRST gauge-fixing, where the BRST symmetry is maintained even under the BRST light-cone gauge-fixing. 展开更多
关键词 light-FRONT QUANTIZATION HAMILTONIAN QUANTIZATION path Integral QUANTIZATION BRST QUANTIZATION Constrained Dynamics Gauge SYMMETRY Chern-Simons-Higgs Theory Broken SYMMETRY Phase HIGGS Potential Spontaneous SYMMETRY Breaking
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Light-Front Hamiltonian and Path Integral Formulations of the Conformally Gauge-Fixed Polyakov D1 Brane Action with a Scalar Dilation Field
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作者 Usha Kulshreshtha Daya Shankar Kulshreshtha 《Journal of Modern Physics》 2011年第8期826-833,共8页
Recently we have studied the instant-form quantization (IFQ) of the conformally gauge-fixed Polyakov D1 brane action with and without a scalar dilaton field using the Hamiltonian and path integral formulations in the ... Recently we have studied the instant-form quantization (IFQ) of the conformally gauge-fixed Polyakov D1 brane action with and without a scalar dilaton field using the Hamiltonian and path integral formulations in the equal world-sheet time framework on the hyperplanes defined by the world- sheet time σ0=τ=constant . The light-front quantization (LFQ) of this theory without a scalar dilaton field has also been studied by us recently. In the present work we study the LFQ of this theory in the equal light-cone world-sheet time framework, on the hyperplanes of the light-front defined by the light-cone world-sheet time σ+=τ+σ=constant , using the Hamiltonian and path integral formulations. The light-front theory is seen to be a constrained system in the sense of Dirac. The light-front theory is seen to possess a set of twenty seven primary second-class contraints. In the present work Hamiltonian and path integral quantizations of this theory are studied on the light-front. 展开更多
关键词 light-FRONT QUANTIZATION HAMILTONIAN QUANTIZATION path Integral QUANTIZATION Constrained Dynamics Constraint QUANTIZATION GAUGE SYMMETRY STRING GAUGE SYMMETRY STRING Theory D-brane Actions Polyakov Action light-Cone QUANTIZATION
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Instant-Form and Light-Front Hamiltonian and Path Integral Formulations of the Conformally Gauge-Fixed Polyakov D1-Brane Action in the Presence of a Scalar Axion Field and an <i>U</i>(1) Gauge Field
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作者 Usha Kulshreshtha Daya S. Kulshreshtha 《Journal of Modern Physics》 2013年第4期57-69,共13页
Recently we have studied the instant-form quantization (IFQ) and the light-front quantization (LFQ) of the conformally gauge-fixed Polyakov D1 brane action using the Hamiltonian and path integral formulations. The IFQ... Recently we have studied the instant-form quantization (IFQ) and the light-front quantization (LFQ) of the conformally gauge-fixed Polyakov D1 brane action using the Hamiltonian and path integral formulations. The IFQ is studied in the equal world-sheet time framework on the hyperplanes defined by the world-sheet time σ0=τ=constant and the LFQ in the equal light-cone world-sheet time framework, on the hyperplanes of the light-front defined by the light-cone world-sheet time σ+= (τ+σ) =constant. The light-front theory is seen to be a constrained system in the sense of Dirac in contrast to the instant-form theory. However, owing to the gauge anomalous nature of these theories, both of these theories are seen to lack the usual string gauge symmetries defined by the world-sheet reparametrization invariance (WSRI) and the Weyl invariance (WI). In the present work we show that these theories when considered in the presence of background gauge fields such as the NSNS 2-form gauge field Bαβ(σ,τ) or in the presence of U(1) gauge field Aα(σ,τ) and the constant scalar axion field C(σ,τ), then they are seen to possess the usual string gauge symmetries (WSRI and WI). In fact, these background gauge fields are seen to behave as the Wess-Zumino or Stueckelberg fields and the terms containing these fields are seen to behave as Wess-Zumino or Stueckelberg terms for these theories. 展开更多
关键词 Lagrangian and HAMILTONIAN Approach HAMILTONIAN QUANTIZATION path Integral QUANTIZATION light-FRONT QUANTIZATION Theory of Quantized Fields Constrained Dynamics D-Brane Actions Polyakov Action Strings and Branes String GAUGE Symmetry GAUGE FIELD Theories
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Light-Front Hamiltonian, Path Integral and BRST Formulations of the Chern-Simons Theory under Appropriate Gauge-Fixing 被引量:6
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作者 Usha Kulshreshtha Daya Shankar Kulshreshtha James P. Vary 《Journal of Modern Physics》 2010年第6期385-392,共8页
The Chern-Simons theory in two-space one-time dimensions is quantized on the light-front under appropriate gauge-fixing conditions using the Hamiltonian, path integral and BRST formulations.
关键词 HAMILTONIAN QUANTIZATION path Integral QUANTIZATION BRST QUANTIZATION CHERN-SIMONS Theories light-CONE QUANTIZATION light-FRONT QUANTIZATION Constrained Dynamics Quantum Electrodynamics Models in Lower Dimensions
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培育世界一流科技期刊背景下青年编辑人才培养与职业发展路径探索——以Light学术出版中心为例 被引量:22
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作者 张莹 郭宸孜 +5 位作者 丁帅 袁境泽 郭巳秋 孙婷婷 郝振东 白雨虹 《编辑学报》 CSSCI 北大核心 2024年第2期227-231,共5页
青年编辑成长一直备受期刊界的关注,其专业素质和职业能力在很大程度上影响着科技期刊未来的发展。培育世界一流科技期刊背景下,探索青年编辑人才的培养策略与职业发展路径,为青年编辑提供可行的职业发展方案,将促进青年编辑的成长与发... 青年编辑成长一直备受期刊界的关注,其专业素质和职业能力在很大程度上影响着科技期刊未来的发展。培育世界一流科技期刊背景下,探索青年编辑人才的培养策略与职业发展路径,为青年编辑提供可行的职业发展方案,将促进青年编辑的成长与发展,推动一流科技期刊建设。本文通过分析与总结中国科学院长春光学精密机械与物理研究所Light学术出版中心,在培育世界一流科技期刊过程中培养国际化、专业化、多元化青年编辑的策略,探讨青年编辑人才培养与职业发展路径,提出青年编辑合理的人才晋升、薪酬奖励、继续教育和职业发展通道。 展开更多
关键词 世界一流科技期刊 青年编辑 职业发展路径 light学术出版中心
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基于双光路中心偏测量仪的红外透镜同轴度、垂直度测量
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作者 张步华 谢启明 +7 位作者 周旭环 陈骥 叶洪伟 赵康宁 王春阳 郭春荣 应常宇 赵正东 《红外技术》 北大核心 2026年第2期132-139,共8页
中心偏差是光学透镜的一类重要指标,直接影响光学系统成像质量。对抛光完工透镜,除了面倾角、球心差和偏心差等指标外,设计师也常用同轴度、垂直度来表征透镜中心偏差,给透镜中心偏差的测量带来新的课题。在已有的面倾角、球心差和偏心... 中心偏差是光学透镜的一类重要指标,直接影响光学系统成像质量。对抛光完工透镜,除了面倾角、球心差和偏心差等指标外,设计师也常用同轴度、垂直度来表征透镜中心偏差,给透镜中心偏差的测量带来新的课题。在已有的面倾角、球心差和偏心差等测量技术基础上,基于双光路中心偏测量仪,提出一种红外透镜同轴度、垂直度的测量方法,分析了影响测量精度的因素,及采用同轴度、垂直度来表征透镜中心偏差的优势。采用该测量技术获得的同轴度、垂直度检验结果得到设计师的认可,并广泛应用于红外透镜的加工生产。 展开更多
关键词 双光路 中心偏差 透镜 同轴度 垂直度
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基于高精度转台的双目结构光点云多视角配准路径规划方法
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作者 朱君益 蔡万源 +1 位作者 毛义梅 陶卫 《仪器仪表学报》 北大核心 2026年第1期158-170,共13页
针对工业现场固定工件的批量三维重建中的效率问题,提出了一种融合双目条纹结构光与高精度转台的配准优化方法以及扫描路径的规划策略,以解决传统扫描方法中配准效率低下、扫描次数冗余及重叠率不足导致的精度下降问题。该方法通过预设... 针对工业现场固定工件的批量三维重建中的效率问题,提出了一种融合双目条纹结构光与高精度转台的配准优化方法以及扫描路径的规划策略,以解决传统扫描方法中配准效率低下、扫描次数冗余及重叠率不足导致的精度下降问题。该方法通过预设工件固定位置消除初始位姿差异对配准结果的影响,依托高精度转台实现多视角点云的高效粗配准,再结合迭代最近点(ICP)算法完成精配准。首先构建被测工件三维点云模型和双目条纹结构光扫描仪的三视锥模型,完成系统参数标定,为配准精度与路径规划提供基础;再建立转台旋转角度与扫描视场的映射关系,采用射线投射法模拟真实光线投射到目标点云表面精准计算可视点云,明确不同角度位姿下的有效扫描区域;最终基于该映射关系,求解得到保证重叠率下完成工件完整三维重建所需的最少扫描次数及对应最优旋转角度,实现扫描路径优化。相比传统均匀旋转点云扫描方法,该方法对工件1的多视角平均配准时间缩短至24.2 s,效率提升约43%,扫描次数减少3次;对工件2的平均配准时间降至58.2 s,效率提升约40.5%,扫描次数减少7次。配准精度上,两工件的平均误差分别达到0.0114和0.0082 mm,较传统方法精度提升幅度分别为64.64%和81.62%。该方法在保证精度的同时提升了扫描效率,适用于工业现场固定位置工件批量快速检测。 展开更多
关键词 双目结构光 多视角点云配准 路径规划 高精度转台
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基于深度学习的自动拾取网球机器人
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作者 梁宏宇 闫坤 郝航勃 《电子测量技术》 北大核心 2026年第3期213-222,共10页
本文提出了一种基于深度学习的自动拾取网球机器人,旨在解决网球场地人工捡球效率低、耗时长的问题。该机器人通过集成树莓派5B主控板、STM32RCT6单片机、USB摄像头和无刷直流电机等硬件模块,结合轻量化的YOLOv11、改进的DBSCAN聚类路... 本文提出了一种基于深度学习的自动拾取网球机器人,旨在解决网球场地人工捡球效率低、耗时长的问题。该机器人通过集成树莓派5B主控板、STM32RCT6单片机、USB摄像头和无刷直流电机等硬件模块,结合轻量化的YOLOv11、改进的DBSCAN聚类路径规划算法、双闭环PID算法以及碾压滚轴式的捡球机械结构,实现了对网球的高效识别、路径优化和自主拾取。研究中对YOLOv11进行了轻量化改进,采用StarNet主干网络、C3k2_Faster模块和共享卷积轻量化检测头SCLD-Head,显著降低了模型的计算需求。实验结果表明,改进后的模型参数量减少了80.8%,GFLOPs仅为1.7,mAP@0.75达到0.980 6,检测速度达到129.7fps。此外,基于DBSCAN聚类算法的路径规划通过密度聚类和距离加权模型优化了捡球路径,提高了机器人在复杂环境下的适应性和鲁棒性。实验结果表明,该模型成功部署于树莓派平台后,系统能够在不同光照条件下准确识别网球,并达到9~12fps的检测速度,单次可拾取7~9个网球,能够显著提升网球拾取效率,具有重要的应用价值和市场潜力。 展开更多
关键词 网球拾取机器人 树莓派 YOLOv11轻量化 路径规划 双闭环PID 网球拾取结构
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基于BIM的智慧建筑照明实现路径
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作者 夏婷婷 《灯与照明》 2026年第2期40-42,共3页
随着智慧建筑与绿色低碳理念进一步深入发展,传统照明系统在设计及运维环节的局限变得日益明显,而建筑信息模型(BIM)技术为照明系统向数字化、智能化升级开辟了全新途径,本文试图研究智慧建筑照明与BIM技术深度融合的实施方式。探讨了... 随着智慧建筑与绿色低碳理念进一步深入发展,传统照明系统在设计及运维环节的局限变得日益明显,而建筑信息模型(BIM)技术为照明系统向数字化、智能化升级开辟了全新途径,本文试图研究智慧建筑照明与BIM技术深度融合的实施方式。探讨了智慧照明系统的三层架构与BIM技术的核心要点,提出了以“几何-信息-逻辑-数据-决策”五层模型为核心的深度融合内容含义,构建了以BIM模型为数字主线,贯穿设计、施工、运维全生命周期的系统性实现方案框架,并细致说明了各阶段的具体实施途径,为智慧照明系统全生命周期数字化管理提供理论根据和实践借鉴。 展开更多
关键词 智慧建筑 智慧照明 BIM技术 深度融合 实现路径
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基于Global Search算法优化近红外测距光学系统
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作者 冯浩 王丽娇 +6 位作者 莫维全 袁必诚 杨志颖 张楠 王开金 刘琨 孙昊 《应用光学》 北大核心 2026年第2期243-252,共10页
为实现户外红外测距系统在有限封闭空间内的精准探测,在不影响探测结果的基础上压缩光学系统体积,采用二维双平面反射系统,设计了一套光学总长为4 m、最大反射镜为12.8 cm的折返式光路。该折返式光路将n片平面反射镜分为2×(n+1)段... 为实现户外红外测距系统在有限封闭空间内的精准探测,在不影响探测结果的基础上压缩光学系统体积,采用二维双平面反射系统,设计了一套光学总长为4 m、最大反射镜为12.8 cm的折返式光路。该折返式光路将n片平面反射镜分为2×(n+1)段光程,利用全局搜索算法(Global Search)对反射镜数量和光学直径进行优化,实现每条探测光线都能照射到探测物体并成功折返回探测器;满足探测要求后,利用信号波原理进行理论验证分析,避免光程折损引起探测误差;最后,通过分析系统在封闭空间内杂散光线的仿真结果,对系统进行杂散光抑制,对实验与原路径的探测结果进行对比,验证了设计光路的正确性和准确性。 展开更多
关键词 光路设计 Global Search算法 杂散光 信号波
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基于激光视觉传感的目标运动轨迹自动跟踪方法研究
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作者 解涛瑞 李云霄 《激光杂志》 北大核心 2026年第3期49-54,共6页
为在复杂环境中,实时更新目标物体位置信息,提出基于激光视觉传感的目标运动轨迹自动跟踪方法。该方法利用激光视觉传感器,实时采集目标物体图像;通过标定激光视觉传感器的结构光,实时、准确获取目标物体的三维信息;在目标运动图像内,提... 为在复杂环境中,实时更新目标物体位置信息,提出基于激光视觉传感的目标运动轨迹自动跟踪方法。该方法利用激光视觉传感器,实时采集目标物体图像;通过标定激光视觉传感器的结构光,实时、准确获取目标物体的三维信息;在目标运动图像内,提取HOG特征;通过循环移位方式,扩充HOG特征样本,训练核相关滤波器;利用完成训练的核相关滤波器,实时更新目标物体在图像中位置;根据坐标转换关系,将目标物体在图像中的位置转换为实际空间中的位置;拟合全部实际位置点得到光滑曲线,即目标运动轨迹自动跟踪结果。实验证明:该方法可有效采集目标物体图像,并提取HOG特征;可有效扩充HOG特征样本,实现目标运动轨迹自动跟踪,且自动跟踪轨迹与实际轨迹非常接近;该方法自动跟踪的成功率均较高,在不同遮挡概率和光照条件下表现出良好的跟踪性能。 展开更多
关键词 激光视觉传感 目标运动轨迹 自动跟踪 结构光 HOG特征 核相关滤波器
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面向产业需求的轻化工程应用型人才培养路径分析
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作者 马然 《造纸科学与技术》 2026年第1期153-156,共4页
随着轻化工产业持续向绿色化、智能化与高端化方向演进,造纸及相关行业对轻化工程应用型人才的工程实践能力、技术适应能力与职业素养等方面提出了更高要求。当前,高校轻化工程人才培养在培养目标设定、课程体系安排、实践教学组织及产... 随着轻化工产业持续向绿色化、智能化与高端化方向演进,造纸及相关行业对轻化工程应用型人才的工程实践能力、技术适应能力与职业素养等方面提出了更高要求。当前,高校轻化工程人才培养在培养目标设定、课程体系安排、实践教学组织及产教融合推进等环节,与产业实际需求之间仍存在一定差距。基于此,结合轻化工程产业发展现状,系统分析产业对应用型人才能力结构的新要求,梳理高校人才培养中较为突出的问题,并在此基础上,从培养目标优化、课程体系调整、师资队伍建设及校企协同机制完善等方面,提出面向产业需求的人才培养路径,以期为改进轻化工程应用型人才培养策略提供参考。 展开更多
关键词 产业需求 轻化工程 应用型人才 培养路径 产教融合
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基于Silverlight网页游戏的寻径优化算法 被引量:3
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作者 李子强 宋余庆 +1 位作者 陈健美 冯江 《计算机工程与应用》 CSCD 2013年第5期59-63,共5页
为了解决A*路径搜索算法在Silverlight网页游戏中的搜索费时和路径曲折等问题,在结合光线跨越算法和引入父结点指针的二叉堆存储开启列表的A*算法的基础上,提出了一种基于Silverlight网页游戏的寻径优化算法。该算法在现有研究的基础上... 为了解决A*路径搜索算法在Silverlight网页游戏中的搜索费时和路径曲折等问题,在结合光线跨越算法和引入父结点指针的二叉堆存储开启列表的A*算法的基础上,提出了一种基于Silverlight网页游戏的寻径优化算法。该算法在现有研究的基础上使用光线跨越算法减小A*算法搜索规模,同时将动态关键点技术与光线跨越算法结合来优化算法返回的路径。将该算法在游戏所使用的网格地图中进行实验,实验结果表明,该算法能够有效地根据系统设定的通行条件寻找出一条最优的实际可行的路径,同时缩短寻路的时间消耗和所寻的路径长度,提高游戏的可玩性。 展开更多
关键词 A*算法 光线跨越算法 动态关键点 启发式搜索 地图寻径 Silverlight网页游戏
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Light trapping characteristics of glass substrate with hemisphere pit arrays in thin film Si solar cells 被引量:2
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作者 陈乐 王庆康 +2 位作者 王阳培华 黄堃 沈向前 《Chinese Physics B》 SCIE EI CAS CSCD 2015年第4期16-21,共6页
In this paper, the light trapping characteristics of glass substrate with hemisphere pit (HP) arrays in thin film Si solar cells are theoretically studied via a numerical approach. It is found that the HP glass subs... In this paper, the light trapping characteristics of glass substrate with hemisphere pit (HP) arrays in thin film Si solar cells are theoretically studied via a numerical approach. It is found that the HP glass substrate has good antireflection properties. Its surface reflectance can be reduced by - 50% compared with planar glass. The HP arrays can make the unabsorbed light return to the absorbing layer of solar cells, and the ratio of second absorption approximately equals 30%. Thus, the glass substrate with the hemisphere pit arrays (HP glass) can effectively reduce the total reflectivity of a solar celt from 20% to 13%. The lip glass can also prolong the optical path length. The numerical results show that the total optical path length of the thin film Si solar cell covered with the HP glass increases from 2ω to 409. These results are basically consistent with the experimental results. 展开更多
关键词 numerical approach light trapping hemispherical pit (HP) optical path length solar cells
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基于无人机机载LiDAR航测的建筑工程测绘方法
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作者 俞正勇 《北京测绘》 2026年第2期243-248,共6页
建筑工程场景中包含多种形态的地物,地物之间的相互遮挡会导致图像信息缺失,影响建筑工程测绘中的图像分割结果,为此本文提出了基于无人机机载激光雷达(LiDAR)航测的建筑工程测绘方法。根据地形约束和转角约束进行无人机路径规划,选用... 建筑工程场景中包含多种形态的地物,地物之间的相互遮挡会导致图像信息缺失,影响建筑工程测绘中的图像分割结果,为此本文提出了基于无人机机载激光雷达(LiDAR)航测的建筑工程测绘方法。根据地形约束和转角约束进行无人机路径规划,选用多旋翼无人机搭载LiDAR设备采集航测数据,确保无人机全面覆盖测绘区域;运用均值漂移聚类算法得到建筑工程测绘种子点云信息,通过区域生长分割方法获得建筑测绘点云轮廓数据,这种逐步扩展的方式使其能够适应高程数据中不同密度的区域,为实现点云图像高质量分割;均匀化处理分割后的高程数据,把八叉树拓扑结构作为建筑工程测绘模型框架,采用泊松重建算法重建高程数据后生成高精度建筑工程测绘结果。实验结果表明,所提方法能有效提高测绘定位精度,测绘模型重建效果良好,可以满足建筑工程测绘的实际技术需求。 展开更多
关键词 无人机 激光雷达(LiDAR)航测 建筑工程测绘 路径规划 泊松重建
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基于P-PP的轻型商用车路径跟踪控制
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作者 王志红 曾嘉荣 +3 位作者 胡杰 张志凌 杨东浩 纪越丰 《汽车工程》 北大核心 2025年第4期669-679,共11页
为提高轻型商用车在复杂曲率工况下路径跟踪的精度和稳定性,本文提出一种预测纯跟踪(predictive-pure persuit,P-PP)控制方法。首先,根据车辆离散运动学模型设计P-PP控制器,并基于航向误差设计PID补偿器,提高跟踪精度与稳定性。其次,针... 为提高轻型商用车在复杂曲率工况下路径跟踪的精度和稳定性,本文提出一种预测纯跟踪(predictive-pure persuit,P-PP)控制方法。首先,根据车辆离散运动学模型设计P-PP控制器,并基于航向误差设计PID补偿器,提高跟踪精度与稳定性。其次,针对固定预测时域算法难以在复杂曲率工况下同时保证精度和稳定性的问题,提出变预测时域优化算法,建立以预测时域内的车辆横向误差和曲率误差为代价的评价函数,采用贝叶斯优化获取最优预测时域,解决精度和稳定性之间的矛盾。最后,进行TruckSim/Simulink联合仿真和实车试验,实车试验中基于贝叶斯优化的P-PP控制器的横向、航向误差、转向盘转角均方根分别为0.113 m、0.045 rad、153.2°,均优于基于模糊控制的P-PP和MPC控制器中的相应指标,表明所提出的控制器在复杂曲率下能保持良好的跟踪精度与稳定性。 展开更多
关键词 轻型商用车 路径跟踪 P-PP PID补偿 贝叶斯优化
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