复杂背景下海天线的连通域检测法

海天线的检测对于划分海空背景、识别红外舰船目标具有重要作用.本文提出一种基于线段表连通域原理的海天线检测方法.首先去除原始红外图像的强水纹干扰和背景干扰,再通过梯度运算和最大值滤波找出海天线的位置.最后基于线段表连通域原理对二值化后的图像进行检测,以提取海天线的非线性边缘信息.实验表明,该方法的检测精度高,而且当海天线上存在舰船时,不会对舰船轮廓产生影响,克服了Hough变换法只能检测出直线的缺点,具有较强的实用性.     

Isocyanic acid and ammonia in vehicle emissions

Vehicles are considered to be an important source of ammonia (NH₃) and isocyanic acid (HNCO). HNCO and NH₃ have been shown to be toxic compounds. Moreover, NH₃ is also a precursor in the formation of atmospheric secondary aerosols. For that reason, real-time vehicular emissions from a series of Euro 5 and Euro 6 light-duty vehicles, including spark ignition (gasoline and flex-fuel), compression ignition (diesel) and a plug-in electric hybrid, were investigated at 23 and −7 °C over the new World harmonized Light-duty vehicle Test Cycle (WLTC) in the Vehicle Emission Laboratory at the European Commission Joint Research Centre Ispra, Italy. The median HNCO emissions obtained for the studied fleet over the WLTC were 1.4 mg km⁻¹ at 23 °C and 6 mg km⁻¹ at −7 °C. The fleet median NH₃ emission factors were 10 mg km⁻¹ and 21 mg km⁻¹ at 23 and −7 °C, respectively. The obtained results show that even though three-way catalyst (TWC), selective catalytic reduction (SCR), and NOx storage catalyst (NSC) are effective systems to reduce NOx vehicular emissions, they also lead to considerable emissions of the byproducts NH₃ and/or HNCO. It is also shown that diesel light-duty vehicles equipped with SCR can present NH₃ emission factors as high as gasoline light-duty vehicles at both, 23 and −7 °C over the WLTC. Therefore, with the introduction in the market of this DeNOx technology, vehicular NH₃ emissions will increase further.     

SBS改性沥青老化过程性能预测方程研究

建立SBS改性沥青在老化过程中性能衰变的非线性预测方程，通过薄膜烘箱试验验证了预测方程的可靠性，基于预测方程分析了SBS改性沥青老化过程中性能指标的变化速率。研究结果表明，非线性方程x(t)=(Lx₀)/[1+(L-1)e^-rt]可用以预测针入度、软化点、延度在SBS改性沥青老化过程中的变化规律；沥青针入度、软化点、延度的变化速率随老化时间的延长而逐渐下降，其中延度指标在老化初期的变化速率下降最快；可通过建立宏观性能指标与红外光谱a₁₇₀₀/a₁₆₀₀的关系方程，进行SBS改性沥青老化程度的预测评估。     

Influence of exhaust parameters on mid-infrared radiative characteristics of the plume北大核心CSCD

[Objectives] Infrared radiative (IR) characteristics of the plume are the main part of ship infrared radiation. The influence analysis of exhaust parameters on radiative characteristics is very important for developing ship stealth and anti-stealth technology. [Methods]In this work, the line-by-line method is applied to solve radiative transfer in gaseous media. Infrared radiative images of plumes under different temperatures and flow rates are obtained. Radiance, spectral radiative intensity, and spectrum-integrated radiative intensity over 3−5 µm are calculated and analyzed. [Results]Results show that there are obvious peaks of spectral radiative intensity curves at 4.18µm and 4.43 µm, and an obvious valley at 4.26 µm. [Conclusions] The infrared radiation characteristics of the ships exhaust plume are greatly affected by the exhaust temperature, but less affected by the exhaust flow rate. © 2023 The Author(s).     

沥青再生过程中界面新旧沥青混溶成效对混合料疲劳性能的影响

为研究相同级配、不同拌和因素下再生沥青混合料界面新旧沥青混溶成效对混合料疲劳性能的影响，基于红外光谱法将再生过程中新旧沥青“部分混溶”的定性问题转向定量，建立了再生沥青混合料混溶成效量化评价方案，研究了不同RAP掺量、拌和温度和干拌时间因素下界面新旧沥青混溶成效与再生料疲劳寿命的联系，进而优选了拌和方案。结果显示：不同拌和因素下，混合料疲劳性能随着界面新旧沥青混溶成效变化而变化，优选拌和方案为40%RAP掺量、165℃拌和温度和90 s干拌时间。