Learning from nature: Fabrication of colloidal PCs with controllable wettability

Colloidal photonic crystals (PCs) with desired wettabilities are of particular importance in various applications. Inspired by biological PCs, such as those of butterfly wings and peacock feathers, which all have evolved to have specific wettability, Professor Song Yanlin and his group in the Laboratory of New Materials, Institute of Chemistry, Chinese Academy of Sciences developed unique approaches to engineer colloidal PCs with desired wettability, based on the well-designed building blocks of latex particles. The range of wettability of these col- loidal PC films could be tailored from superhydrophobicity to superhydrophilicity and even superoleophobicity, by varying the surface     

基于层次分析的长短记忆网络(AHP-LSTM)的食品安全网络舆情预警模型

随着互联网技术的迅猛发展,网络已成为社会舆情的重要阵地,而网络舆情是食品风险预警的一个方向。传统舆情预警模型在指标体系的基础上结合反向传播神经网络（back propagation neural network,BP）等神经网络模型进行分析,存在运行不稳定、预测精度不高等问题。为了解决这些问题,采用具有较高预测精度的长短记忆（long short-term memory,LSTM）网络算法,在网络事件指标体系的基础上引入层次分析法（analytic hierarchy process,AHP）并融合食品安全事件指标数据,将融合结果作为LSTM的期望输出,以建立更为稳定、精度更高的风险预警模型AHP-LSTM。实验结果表明,与传统模型相比,AHP-LSTM对于事件指标数据具有较强的处理能力和较高的预警精度。因此构建基于AHP-LSTM的食品安全事件预警方法,可为相关部门有效防范和管理食品安全网络事件提供一定的理论依据和数据支撑。     

数据和知识融合驱动的智能过程系统工程研究进展

智能过程系统工程教育部工程研究中心建设十余年来,开展了一系列卓有成效的基于数据和知识融合驱动的智能化过程系统工程（PSE）科学研究、技术创新和工程应用。本文重点介绍过程工业节能减排降耗和安全运行相关的关键技术——建模与优化、报警管理与故障诊断以及能效分析与评价三大应用的研究进展,最后结合大数据、云计算、工业4.0、智能制造、人工智能等技术展望了PSE的未来发展方向。     

连续束模式下β衰变研究的实验装置

为开展远离稳定线原子核的β衰变实验研究,我们研制了一套新的粒子注入和β探测装置.这套探测装置具有能量覆盖范围大、能量分辨好和工作稳定等特点.在束实验结果显示这套探测装置可以精确给出衰变母核和β电子之间的时间关系和位置关联信息,使我们可以在连续束工作模式下对衰变出射β电子进行准确的归属判定,大大减少了衰变谱的本底,确保了实验数据的精度,为我们在极低流强下开展衰变谱学的研究提供了一种可靠的方法.     

利用直接核反应研究轻丰中子核的奇特结构

直接核反应是研究丰中子区核结构的重要手段．我们发展了质子标记的敲出反应实验方法,并用于^6He和^8He的结构研究,给出了^7He共振态至今最精确的测量结果．发展了多中子关联测量技术,并基于此重建了^8He激发态以及研究了^8He中的双中子关联．通过屹Be的非弹散射实验,观测到若干共振态,构成^6He＋^6He和^4He＋^8He两条分子转动带,支持挖Be的α-4n-α集团结构．     

广西生态农业的模式与特点

生态农业是一种新兴的综合农业生产体系，本文分析广西生态农业的主要模式总结广西生态农业的主要特点。     

Seasonal variation and sources of low molecular weight organic acids in precipitation in the rural area of Anshun

Low molecular weight (LMW) organic acids are important and ubiquitous chemical constituents in the atmosphere. A comprehensive study of the chemical composition of precipitation was carried out from June 2007 to June 2008 at a rural site in Anshun, in the west of Guizhou Province, China. During this period, 118 rainwater samples were collected and the main LMW carboxylic acids were determined using ion chromatography. The average pH of rainwater was 4.89 which is a typical acidic value. The most abundant carboxylic acids were formic acid (volume weight mean concentration: 8.77 μmol L⁻¹) and acetic acid (6.90 μmol L⁻¹), followed by oxalic acid (2.05 μmol L⁻¹). The seasonal variation of concentrations and wet deposition fluxes of organic acids indicated that direct vegetation emissions were the main sources of the organic acids. Highest concentrations were observed in winter and were ascribed to the low winter rainfall and the contribution of other air pollution sources northeast of the study area. The ratio of formic and acetic acids in the precipitation ([F/A] _T ) was proposed as an indicator of pollution source. This suggested that the pollution resulted from direct emissions from natural or anthropogenic sources. Comparison with acid precipitation in other urban and rural areas in Guizhou showed that there was a decreasing contribution of LMW organic acids to free acidity and all anions in rainwater from urban to remote rural areas. Consequently, it is necessary to control emissions of organic acids to reduce the frequency of acid rain, especially in rural and remote areas.     

熵产生最小时不可逆Otto循环热机活塞运动最优路径

给定循环总时间和耗油量的情况下,以存在传热、摩擦等内、外不可逆性的Otto循环热机为研究对象,考虑工质与环境之间的传热分别服从牛顿传热规律q∝Δ（T）和线性唯象传热规律q∝Δ（T-1）,以循环熵产生最小为目标对整个循环活塞运动的最优路径进行了研究.利用最优控制理论得出了两种传热规律下无加速度约束和限制加速度时对应于循环最小熵产生时各冲程活塞最优运动规律及循环总时间的最优分配.限制加速度时各个冲程的活塞运动最优构型均由三段组成,均包含了一个初始最大加速段和一个末端最大加速段.给出了最优构型的数值算例,并与牛顿传热规律和线性唯象传热规律时最大输出功条件下的最优构型进行了比较.计算结果表明优化活塞运动规律后可使热机熵产生减小30%以上,这主要是通过减少功率冲程初始段传热损失引起的熵产生实现的.     

Compass导航信号性能评估研究

卫星导航信号体制决定了导航系统的先天性能,是系统设计和升级过程中必须考虑的关键因素之一.本文提出了卫星导航信号体制的性能评估方法,并评估了Compass信号的性能.该评估方法包含了精度、抗干扰、抗多径、兼容性四个方面的内容,分别采用了Gabor带宽、解调抗窄带/匹配谱干扰品质因数、跟踪抗窄带/匹配谱干扰品质因数、多径误差包络、连续平均多径误差包络、谱分离系数、谱安全指数等指标来刻画这些方面的性能.基于我国对外公布的最新信号体制框架,将Compass信号体制和GPS,Galileo信号体制进行对比分析.分析结果表明：对于民用信号,Compass的性能最佳;对于特殊用户,Compass的精度、抗多径能力和GPS,Galileo相当,但抗干扰能力低于GPS和Galileo.这意味着Compass系统在未来的特殊条件下处于劣势.最后,给出了信号体制优化的建议.