空间冷光学长波红外相机的设计与验证

为满足红外成像产品在复杂多变环境下的适应性并实现产品的使用功能,对空间冷光学长波红外相机设计进行了研究。首先进行了相机的结构设计;然后运用Partarn/Nastran有限元软件对相机进行了分析,探究了温降和重力对各透镜面形的影响,计算了相机的前三阶模态,并对相机进行了波像差测试;最后在真空低温环境下完成了相机的调制传递函数(Modulation Transfer Function, MTF)测试。试验结果表明,相机中心视场面形的均方根(Root Mean Square, RMS)值优于1/50λ,MTF计算值为0.18719,满足低温红外相机成像的精度要求。     

两批次番茄炒蛋蛋白质近红外光谱检测模型的维护方法

为解决光谱数据差异导致模型不稳定的问题,研究了不同批次中式菜肴营养素含量预测模型的传递方法。以间隔3个月制作的番茄炒蛋样本为例,采集光谱数据并利用理化方法测定蛋白质含量(每批次120个样本);选择预测效果较好的第二批次模型作为主模型,将分段直接标准化(Piecewise Direct Standardization, PDS)算法、模型更新(Model Updating, MP)和斜率/截距(Slope/Bias, S/B)修正法联合(PDS-MP-S/B)用于菜肴类模型传递,分析不同PDS窗口数和标准集数对预测结果的影响。当PDS窗口数为11且标准集数为100时,PDS-MP-S/B算法对蛋白质含量的预测结果明显优于无模型传递和单独使用3种算法时,预测模型的预测集决定系数R2(Pred)为0.9628,相对预测偏差(Relative Prediction Deviation, RPD)为5.6731,预测均方根误差(Root Mean Square Error of Prediction, RMSEP)为0.3157。从光谱、模型、结果三个方面实现了模型传递,提高了模型的通用性,减少了建模成本,为中式菜肴的快检提供了理论支持。     

一种增强型PTP光纤级联精细时频同步方法

该文提出了一种增强型PTP光纤级联精细时频同步方法,该方法以PTP同步技术为基础,结合同步以太网时钟传递技术和基于数字双混频时差法的多级级联精细时钟同步技术,对PTP技术进行改进和增强,然后基于该方法,通过多级时频设备光纤级联的形式实现多节点、大跨度、网络化的时频信号传递与同步输出,并解决多级级联情况下同步精度会逐级恶化的问题,实现ns量级的系统时间同步精度,保证系统各环节在高度统一的时间尺度下进行高效同步与联动工作。通过设计、试验,验证了该方法的可行性和有效性。     

一种特征转移和域自适应的异质缺陷预测方法

软件缺陷预测是软件工程领域中的一个研究热点.跨项目缺陷预测(Cross-Project Defect Prediction, CPDP)采用源项目的缺陷数据来预测目标项目的缺陷倾向性.然而,源项目和目标项目的特征可能会有所不同.因此,研究人员提出了异质缺陷预测(Heterogeneous Defect Prediction, HDP).为了提高HDP模型的性能,本文提出了一种基于特征迁移和域自适应的异质缺陷预测(Feature Transfer and Domain Adaptation, FTDA)方法.首先,FTDA使用基于相关性的特征选择算法从源项目的特征集中选择最优的特征子集.随后,使用欧氏距离进行匹配特征,并为每个目标项目选择最合适的源项目.再次,使用TCA算法解决不同项目之间的分布差异问题.最后,使用SMOTETomek算法处理类不平衡问题.为了验证FTDA方法的有效性,本文对AEEEM,PROMISE,NASA和Relink数据集中的24个项目进行了实证研究.实证研究表明,FTDA显著提高了异质缺陷预测的性能.     

Scattering of elastic P- and SV-waves by a circular coated nanofiber based on Gurtin–Murdoch model of surface elasticity: Scattering cross section results

In this article, an analytical study of elastic P- and SV-wave scattering by a circular nanofiber is presented. The nanofiber is assumed to be surrounded by an inhomogeneous interphase layer, and Gurtin–Murdoch's model of surface elasticity is utilized to study the surface/interface effects in the regions between the fiber and interphase and also interphase and matrix. The simultaneous effects of surface elasticity and interphase inhomogeneity are considered here; by taking the inhomogeneous interphase to be composed of several sublayers, a transfer matrix approach is used to find the unknown field variables and, consequently, the scattering cross sections. The results indicate that considering the effects of surface elasticity and interphase inhomogeneity has a considerable impact on the calculated scattering cross sections.     

Dominance of Plasmonic Resonant Energy Transfer over Direct Electron Transfer in Substantially Enhanced Water Oxidation Activity of BiVO4 by Shape‐Controlled Au Nanoparticles

The performance of plasmonic Au nanostructure/metal oxide heterointerface shows great promise in enhancing photoactivity, due to its ability to confine light to the small volume inside the semiconductor and modify the interfacial electronic band structure. While the shape control of Au nanoparticles (NPs) is crucial for moderate bandgap semiconductors, because plasmonic resonance by interband excitations overlaps above the absorption edge of semiconductors, its critical role in water splitting is still not fully understood. Here, first, the plasmonic effects of shape‐controlled Au NPs on bismuth vanadate (BiVO₄) are studied, and a largely enhanced photoactivity of BiVO₄ is reported by introducing the octahedral Au NPs. The octahedral Au NP/BiVO₄ achieves 2.4 mA cm^?2 at the 1.23 V versus reversible hydrogen electrode, which is the threefold enhancement compared to BiVO₄. It is the highest value among the previously reported plasmonic Au NPs/BiVO₄. Improved photoactivity is attributed to the localized surface plasmon resonance; direct electron transfer (DET), plasmonic resonant energy transfer (PRET). The PRET can be stressed over DET when considering the moderate bandgap semiconductor. Enhanced water oxidation induced by the shape‐controlled Au NPs is applicable to moderate semiconductors, and shows a systematic study to explore new efficient plasmonic solar water splitting cells.     

Efficient and 1,8-diiodooctane-free ternary organic solar cells fabricated via nanoscale morphology tuning using small-molecule dye additive

The ternary strategy for incorporating multiple photon-sensitive components into a single junction has emerged as an effective method for optimizing the nanoscale morphology and improving the device performance of organic solar cells (OSCs).In this study,efficient and stable ternary OSCs were achieved by introducing the small-molecule dye (5E,5'E)-5,5'-(4',4″-(1,2-diphenylethene-1,2-diyl)bis(biphenyl-4',4-diyl))bis(methan-1-yl-1-ylidene)bis(3-ethyl-2-thioxothia zolidin-4-one) (BTPERn) into poly[4,8-bis(5-(2-ethylhexyl)thiophen-2-yl)benzo[1,2-b:4,5-b']dithiopheneco-3-fluorothieno[3,4-b]thiophene-2-carboxylate] (PTB7-Th):[6,6]-phenyl C71 butyric acid methyl ester (PC71BM) blend films processed using a 1,8-diiodooctane (DIO)-free solvent.The incorporation of BTPE-Rn enhanced the short-circuit current density and fill factor of the ternary OSCs compared with those of binary OSCs.An investigation of the optical,electronic,and morphological properties of the ternary blends indicated that the third component of BTPE-Rn not only promoted the photon utilization of blends through the energy-transfer process but also improved the electron mobility of the blends owing to the fullerene-rich nanophase optimization.More importantly,this ternary strategy of utilizing a small-molecule dye to replace the photounstable DIO additive enhanced the operational stability of the OSCs.     

新型双温驱动吸收制冷循环性能

针对跨临界CO_2压缩制冷系统制取冷量以消耗高品位能量为代价的问题,本文依据能量梯级利用原理,提出双温低品位热源驱动的新型CO_2-[emim][Tf_2N]吸收式制冷循环的新流程,在构建该制冷循环数学模型的基础上,搭建测试双温驱动吸收制冷循环性能的实验装置,利用模拟和实验方法分析了操作参数对系统性能的影响规律。在定流量的条件下,研究驱动热源温度、冷却水入口温度以及载冷剂入口温度等操作参数对新系统性能的影响规律,结果表明双温驱动新型吸收制冷系统不仅可实现高效制冷,而且最低制冷温度可达到-15.2℃,研究结果为CO_2-离子液体制冷系统的理论设计计算提供实用的数据基础。     

泵供液式冷风机性能模拟与实验研究

本文建立了不同流程分布的冷风机模型,对各流程分布冷风机性能进行了模拟研究;采用泵供液式制冷量测试法,对以R717为工质的最优流程分布冷风机进行了性能测试。研究表明,单排管双流程布管方式能够使冷风机的性能最优;存在使冷风机制冷量最大的泵送比,在蒸发温度-25℃工况下,当泵送比为3.5时,冷风机的制冷量最大,为44.3 k W;随着蒸发温度的升高,冷风机的传热系数逐渐增大,当蒸发温度为-25℃时,传热系数为27.4 W/(m~2·K),当蒸发温度为0℃时,传热系数为34.4W/(m~2·K),提高了25.5%;随着蒸发温度的升高,冷风机的制冷量逐渐增大,当蒸发温度为-25℃时,制冷量为44.3 k W,当蒸发温度为0℃时,制冷量为64.3 k W,增大了45.15%。采用泵供液式制冷量测试法,测得在不同实验工况下,冷风机制冷量实验值比模拟值低5%左右,验证了冷风机模型的正确性。