Generalization of the Lambertian model and implications for machine vision

Lambert's model for diffuse reflection is extensively used in computational vision. It is used explicitly by methods such as shape from shading and photometric stereo, and implicitly by methods such as binocular stereo and motion detection. For several real-world objects, the Lambertian model can prove to be a very inaccurate approximation to the diffuse component. While the brightness of a Lambertian surface is independent of viewing direction, the brightness of a rough diffuse surface increases as the viewer approaches the source direction. A comprehensive model is developed that predicts reflectance from rough diffuse surfaces. The model accounts for complex geometric and radiometric phenomena such as masking, shadowing, and interreflections between points on the surface. Experiments have been conducted on real samples, such as, plaster, clay, sand, and cloth. All these surfaces demonstrate significant deviation from Lambertian behavior. The reflectance measurements obtained are in strong agreement with the reflectance predicted by the proposed model. The paper is concluded with a discussion on the implications of these results for machine vision.     

卫星姿态控制用无铁心飞轮电机的设计与研究

为了适应现代卫星的高精度、高可靠和轻量化发展需要,姿态控制系统对飞轮电机的输出力矩平稳性、效率、质量、可靠性、体积等指标提出了更高要求。通过对飞轮电机极对数、转矩波动、黏性阻尼系数以及电枢绕组的设计和研究,并通过电磁仿真、力学和热仿真,设计了满足飞轮系统要求的电机。通过实验验证,该外转子无槽无铁心飞轮电机满足卫星姿态控制的精度和稳定性要求。     

1 000MW燃煤机组湿烟囱防腐方案

我国燃煤电厂烟气中的SO2排放控制主要采用湿法脱硫技术,脱硫后的烟气中仍含有少量的SO2和大部分SO3,不设烟气再热器（gas-gas heater,GGH）时烟囱内烟气湿度大,属于湿烟囱,应按强腐蚀性等级考虑。从防腐角度来看,烟囱结构形式的首选方案是多管式烟囱。通过对圆筒、方筒和塔架3种烟囱外筒形式的比较,得出采用普通圆形钢筋混凝土外筒最优的结论。通过对钛钢复合板内筒、玻璃钢内筒、镍基合金内衬和宾高德防腐玻璃砖内衬钢内筒这几种湿烟囱防腐方案的对比分析,优先推荐玻璃钢内筒作为1 000MW燃煤机组湿烟囱防腐方案。     

基于自耦补偿与谐波屏蔽换流变压器的直流输电系统仿真研究

为揭示自耦补偿与谐波屏蔽(新型)换流变压器电磁暂态瞬变过程,模拟直流输电系统中新型换流变压器网侧与阀侧端口电压、电流的输入、输出特性以及交直流之间的相互 作用,利用仿真软件Matlab分别建立了用于6脉动与12脉动直流输电系统的新型换流变压器仿真模型,并将其应用到直流输电系统动态仿真中。仿真结果表明：新型换流变压器取代传统换流变压器在一定程度上优化了直流输电系统的结构,通过对变压器第三绕组的零阻抗设计及绕组抽头处滤波器参数的合理配置,既能降低换流变压器网侧谐波含量、有效减少谐波与无功对换流变压器的损耗,又改善了换流变压器阀侧的线电压与相电流,有利于换流器可靠换相与正常运行。     

整合山水景观、营建生态住区——南工大浦江学院学生住区规划中标方案介绍

通过引入整体空间秩序设计分析方法,对南京工业大学浦江学院学生宿舍、学生食堂项目的设计进行详述,探索山地校园生活区的重点问题和设计方法,并作出相应的介绍:延续校园整体空间秩序;尊重地形的交通体系;注重生态的外部空间;创造有社区文化特色的高校学生生活区。     

一种光伏系统的多峰值最大功率点跟踪策略

局部阴影条件下,光伏阵列的输出功率-电压(P-U)特性曲线存在多个局部峰值(LMPP)。传统的最大功率点跟踪(MPPT)法可能使系统工作于LMPP,错失真正的全局最大功率点(GMPP)。通过分析局部阴影条件下光伏阵列的输出电流-电压(I-U)特性曲线,提出了将电流控制和扰动观察法(PO)结合的MPPT策略,实现了跟踪GMPP的目标。仿真结果表明该算法比扫描整条P-U曲线法节省了50%的时间,实验验证了其易用性。     

反求工程中基于图像的汽车零部件曲面的重建

从明暗恢复形状是计算机视觉中的一个重要的研究课题,其目的是利用单幅图像中明暗变化等信息来恢复其表面形状.本文提出的是一种基于汽车零部件曲面图像的三维数据模型重建方法,根据从明暗恢复形状原理实现汽车零部件灰度图像的深度信息提取,通过可视化编程实现建模过程.     

Collaborative Action of Microglia and Astrocytes Mediates Neutrophil Recruitment to the CNS to Defend against Escherichia coli K1 Infection

Escherichia coli K1 is a leading cause of neonatal bacterial meningitis. Recruitment of neutrophils to the central nervous system (CNS) via local immune response plays a critical role in defense against E. coli K1 infection; however, the mechanism underlying this recruitment remains unclear. In this study, we report that microglia and astrocytes are activated in response to stimulation by E. coli K1 and/or E. coli K1-derived outer membrane vesicles (OMVs) and work collaboratively to drive neutrophil recruitment to the CNS. Microglial activation results in the release of the pro-inflammatory cytokine TNF-α, which activates astrocytes, resulting in the production of CXCL1, a chemokine critical for recruiting neutrophils. Mice lacking either microglia or TNF-α exhibit impaired production of CXCL1, impaired neutrophil recruitment, and an increased CNS bacterial burden. C-X-C chemokine receptor 2 (CXCR2)-expressing neutrophils primarily respond to CXCL1 released by astrocytes. This study provides further insights into how immune responses drive neutrophil recruitment to the brain to combat E. coli K1 infection. In addition, we show that direct recognition of E. coli K1 by microglia is prevented by the K1 capsule. This study also reveals that OMVs are sufficient to induce microglial activation.     

行李箱外板斜楔翻边模设计

对某车型行李箱外板上部斜楔翻边模的工序内容和结构难点进行了分析,介绍了斜楔翻边模搓板驱动滑块结构和翻边随动压料结构的原理及作用,为今后的斜楔翻边模特殊结构设计提供新的思路.     

轻质外保温墙体温度与荷载作用的耦合效应试验研究

由不同物理力学性能材料组成的复合轻质外保温墙体,在多因素的作用下引起整体粉刷墙面的开裂、脱落等破坏现象。试验按照实际工程构造尺寸制作了两组六个试件,通过冷热箱、密封试件真空负压组合试验装置,按1：1相似比模拟温度、重力、风力等作用,对不同因素组合工况测试各构造层在温度与荷载共同作用下的耦合效应,给出了不同工况下保温层及饰面层各测点的温度场分布规律,整理出了耦合效应的应力变化特征相关曲线。试验成果可为研究解决外保温墙面破坏问题提供借鉴。