基于包装功能的时间–温度指示器与食品新鲜度指示器研究进展

目的 从包装功能实现的角度分析研究时间–温度指示器和食品新鲜度指示器的原理、类型与发展趋势，指出开发设计时间–温度指示器和食品新鲜度指示器应完成的包装功能，为有效实现包装交流功能提供研究思路和技术支持。方法 列出现有食品包装功能在物理环境、周围环境和人类环境下的实现矩阵，通过研究时间–温度指示器和食品新鲜度指示器的实现原理和所满足的包装交流功能，探讨这2种技术提高矩阵中分值较低元素的可行性。结果 时间–温度指示器监测食品所经历的时间、温度的完整历程，有助于提高实现矩阵中ComA元素的分值;食品新鲜度指示器提供生理变化或微生物生长引起的食品质量变化的定性或半定量信息，有助于提高实现矩阵中ComH元素的分值。结论 时间–温度指示器和食品新鲜度指示器能够有效提升食品包装的交流功能，保证消费者安全，减少资源浪费，具有广阔的发展前景。     

Airborne bacterial assemblage in a zero carbon building: A case study

Currently, there is little information pertaining to the airborne bacterial communities of green buildings. In this case study, the air bacterial community of a zero carbon building (ZCB) in Hong Kong was characterized by targeting the bacterial 16S rRNA gene. Bacteria associated with the outdoor environment dominated the indoor airborne bacterial assemblage, with a modest contribution from bacteria associated with human skin. Differences in overall community diversity, membership, and composition associated with short (day‐to‐day) and long‐term temporal properties were detected, which may have been driven by specific environmental genera and taxa. Furthermore, time‐decay relationships in community membership (based on unweighted UniFrac distances) and composition (based on weighted UniFrac distances) differed depending on the season and sampling location. A Bayesian source‐tracking approach further supported the importance of adjacent outdoor air bacterial assemblage in sourcing the ZCB indoor bioaerosol. Despite the unique building attributes, the ZCB microbial assemblage detected and its temporal characteristics were not dissimilar to that of conventional built environments investigated previously. Future controlled experiments and microbial assemblage investigations of other ZCBs will undoubtedly uncover additional knowledge related to how airborne bacteria in green buildings may be influenced by their distinctive architectural attributes.     

Gamers,Surfers, Social Media Users: Unpacking the role of interest in English

Across stages of acquisition, second language (L2) competencies are contingent on the variation among individuals learning the language, in both informal and formal learning contexts. This study investigates a group of outliers whose extreme test scores serve as a foundation to examine them as individuals. The study addresses the outliers' characteristics as good L2 readers but poor first language (L1) readers. Combining quantitative (test results, survey, and language logs) and qualitative (focus groups and interviews) data among 21 adolescents in Norway (aged 16–17 years), the study identifies dimensions of individual language use in L1 Norwegian and L2 English. Findings revealed that they explained their English proficiency by the role of interest and their extensive use of English technology and tools outside school. In‐depth analysis identified three profiles: the Gamer, who spends up to 8 hr daily playing online games while using English mainly; the Surfer, who spends hours on the Internet, searching for authentic language situations, commonly involving English; and the Social Media User, who produces and consumes information in English through social media. Additionally, the Gamers read printed novels voluntarily outside the classroom. This study offers unique perspectives and new directions for future L2 research.     

Ground robotics in tunnels: Keys and lessons learned after 10 years of research and experiments

The work reported in this article describes the research advances and the lessons learned by the Robotics, Perception and Real‐Time group over a decade of research in the field of ground robotics in confined environments. This study has primarily focused on localization, navigation, and communications in tunnel‐like environments. As will be discussed, this type of environment presents several special characteristics that often make well‐established techniques fail. The aim is to share, in an open way, the experience, errors, and successes of this group with the robotics community so that those that work in such environments can avoid (some of) the errors made. At the very least, these findings can be readily taken into account when designing a solution, without needing to sift through the technical details found in the papers cited within this text.     

Real-time organic aerosol chemical speciation in the indoor environment using extractive electrospray ionization mass spectrometry

Understanding the sources and composition of organic aerosol (OA) in indoor environments requires rapid measurements, since many emissions and processes have short timescales. However, real-time molecular-level OA measurements have not been reported indoors. Here, we present quantitative measurements, at a time resolution of five seconds, of molecular ions corresponding to diverse aerosol-phase species, by applying extractive electrospray ionization mass spectrometry (EESI-MS) to indoor air analysis for the first time, as part of the highly instrumented HOMEChem field study. We demonstrate how the complex spectra of EESI-MS are screened in order to extract chemical information and investigate the possibility of interference from gas-phase semivolatile species. During experiments that simulated the Thanksgiving US holiday meal preparation, EESI-MS quantified multiple species, including fatty acids, carbohydrates, siloxanes, and phthalates. Intercomparisons with Aerosol Mass Spectrometer (AMS) and Scanning Mobility Particle Sizer suggest that EESI-MS quantified a large fraction of OA. Comparisons with FIGAERO-CIMS shows similar signal levels and good correlation, with a range of 100 for the relative sensitivities. Comparisons with SV-TAG for phthalates and with SV-TAG and AMS for total siloxanes also show strong correlation. EESI-MS observations can be used with gas-phase measurements to identify co-emitted gas- and aerosol-phase species, and this is demonstrated using complementary gas-phase PTR-MS observations.     

Indoor levels of volatile organic compounds at Florentine museum environments in Italy

Indoor Air Quality monitoring in cultural institutions is of particular concern to protect these places and the cultural heritage content. An indoor monitoring campaign was performed in three museums in Florence (Italy) to determine the occurrence and levels of volatile organic compounds (VOCs). VOCs of interest included BTEX (benzene, toluene, ethylbenzene, xylenes), terpenes, aldehydes, organic acids, and cyclic volatile methyl siloxanes (cVMS). The most abundant VOCs in all samples analyzed were BTEX, which were strictly related to the traffic source, followed by siloxanes and terpenes. Among BTEX, toluene was always the most abundant followed by xylenes, ethylbenzene, and benzene. cVMS in exhibition rooms with the presence of visitors showed higher values compared to samples collected when the museums were closed. Terpenes showed not only the influence of vegetation-biogenic sources surrounding a museum but could also be related to the wood used for the construction of showcases and furniture and the use of cleaning products. Data obtained also showed the presence of organic acids and aldehydes whose source can be traced back to exhibits themselves and wood-based furniture. Assessing the levels of organic acids in museums is important because, over time, it can cause deterioration of the artifacts.     

适应不同重力环境的仿壁虎机器人运动仿真

针对不同重力环境下仿壁虎机器人的运动稳定性、运动高效协调性等问题,基于四足机器人的步态规划现状和仿壁虎机器人自身特定的机械结构,设计了仿壁虎机器人在g、0、-g 3种环境下的足端轨迹和运动步态。在ADAMS仿真软件中研究了机器人的运动学和动力学特性,得到了仿壁虎机器人稳定爬行与脚掌黏附力、足端轨迹和运动步态的关系。探讨了仿真结果的合理性和局限性,为仿壁虎机器人在实际环境中的稳定运动奠定了理论基础。     

The effects of augmented virtual science laboratories on middle school students' understanding of gas properties

The Next Generation Science Standards (NGSS) emphasize authentic scientific practices such as developing models and constructing explanations of phenomena. However, research documents how students struggle to explain observable phenomena with molecular-level behaviors with current classroom experiences. For example, physical laboratory experiences in science enable students to interact with observable scientific phenomena, but students often fail to make connections to underlying molecular-level behaviors. Virtual laboratory experiences and computer-based visualizations enable students to interact with unobservable scientific concepts, but students can have difficulties connecting to actual instantiations of the observed phenomenon. This paper investigates how combining physical and virtual experiences into augmented virtual science laboratories can help students build upon intuitive ideas and develop molecular-level explanations of macroscopic phenomena. Specifically, this study uses the Frame, a sensor-augmented virtual lab that uses sensors as physical inputs to control scientific simulations. Eighth-grade students (N = 45) engaged in a Frame lab focused on the properties of gas. Results demonstrate that students using the Frame lab made progress developing molecular-level explanations of gas behavior and refining alternative and partial ideas into normative ideas about gases. This study offers insights for how augmented virtual labs can be designed to enhance science learning and encourage scientific practices as called for in the NGSS.     

The influences of a two-tier test strategy on student learning: A lag sequential analysis approach

Recently, programming skills have become a core competence. Many teaching strategies were developed to improve programming skills. Among them, online tests were widely applied to enhance students learning. Nonetheless, they may not be able to engage students in deep thinking and reflections. Thus, a two-tier test strategy was proposed to address this issue. However, previous research mainly focused on investigating the effectiveness of the two-tier test strategy but there is a lack of studies that investigate why the two-tier test approach is effective. To this end, we developed an online test, where the two-tier test strategy was implemented. Additionally, an empirical study was conducted to explore the influences of the two-tier test approach on students' learning performance and behavior patterns. Pre-test and post-test scores were applied to assess students' learning performance while a lag sequential analysis was used to analyze behavior patterns. Regarding learning performance, the proposed two-tier test can improve students' programming skills. Regarding behavior patterns, the two-tier test approach facilitates students to develop a learning by reviewing strategy, which is useful to improve their programming skills.