茂金属耐热聚乙烯管材料的结构与性能

对3种茂金属耐热聚乙烯（PE-RT）管材料（ M 1,M 2和M 3）的基本物性、热性能、相对分子质量及其分布、力学性能、流变性能等进行分析表征,考察了3种PE-RT管材料的性能差异。结果表明: 3种PE-RT管材料均属于中密度聚乙烯产品,熔体流动速率相近;3种PE-RT管材料中,国产料M 1,M 2的分子质量分布较宽,熔点较低,结晶度小,韧性较好;进口料M 3的熔体拉伸强度较大,可拉伸性最佳,弯曲弹性模量高,具有良好的刚性。     

Research-by-design framework for integrating education and research in an intercultural parallel design studio

Intercultural student exchange can positively impact education, research, and society. Research-by-design has been put forward in design education as an approach to explicitly address the integration of education and research. The problem is that design schools develop their own interpretation of this approach, which brings difficulty in virtually comparing and learning from the generated design proposals. This case is evident in intercultural parallel design studios that deal with diverging socio-cultural and institutional traditions. In addressing this problem and maximizing the benefits of intercultural exchange, this study proposes to adopt a meta perspective and use the design as co-evolution model as a framework for analyzing and comparing design data generated by different research-by-design approaches. The study applies this meta perspective on an intercultural architectural design studio jointly organized by Ton Duc Thang University (Vietnam) and Hasselt University (Belgium).     

Short-and long-term effects of architecture on the brain: Toward theoretical formalization

The physical environment affects people’s behavior and wellbeing. Some effects can be easily noticed through observation, whereas others require an in-depth study to be understood and measured. Although many alterations can be positive, some can also negatively influence wellbeing, decision-making, and mental and physical health. Some of these effects are not easily associated with physical space. Thus, people may be unaware of the real triggers for changes in behavior, mood, and wellbeing. Although many studies have been performed on environmental psychology, detailed research to understand the impacts of architecture on the brain using neuroscience is limited. Some difficulties experienced by researchers in this field are on the isolation of each stimulus to understand its effects individually and measurement of brain changes in people interacting with the environment because some brain scans, such as fMRI, require people to be inside the machine. Nonetheless, the several ways a space can impact its users should be discussed to understand how architecture influences individuals and to help architects and urban planners in designing efficient and healthy spaces. This study aims to describe and analyze the results of previous research works and propose a way of organizing them to facilitate further investigation on this field.     

地下水生态系统服务价值评估

地下水作为人类生产生活中可直接利用的自然资源,是维持自然界生态系统平衡的重要支撑,但人们往往只重视其使用价值,而忽略了其生态价值,造成地下水不合理利用,引发了一系列生态环境问题,因此对地下水生态系统服务进行系统性价值评估显得尤为重要。按利用地下水方式,将地下水生态系统分为三大类、服务类型分为四大类,并以此为基础,对赋存于地下水中的生态系统建立由10项服务指标、9种评估模型构成的价值评估体系。最后以邯郸市为例,2015年为基准年,对其涉及到的7项服务指标进行了价值评估。结果表明,2015年邯郸市赋存于地下水中的生态系统服务总价值合计为105.18亿元,直接使用价值为38.49亿元,间接使用价值为66.69亿元,间接使用价值是直接使用价值的1.73倍。研究认为地下水生态系统服务间接使用价值巨大,应在全面认识地下水价值的基础上,合理开发利用地下水资源,使其服务价值最大化。研究成果可为地下水生态系统服务价值评估提供参考。     

雅砻江流域径流演变特征及成因

利用M-K检验、滑动t检验等方法系统地分析了雅砻江流域两河口、锦屏、官地和二滩4个水文站点径流情况,研究其年内分配、年际变化、趋势特征、突变点等径流过程变化特征,并探讨其成因。结果表明,雅砻江流域年内径流量主要集中在6～10月,约占年径流总量的75.46%;各站点年径流量整体呈下降趋势,从月径流量变化趋势来看,4站均在5、9月呈不显著上升趋势;雅砻江流域径流突变点为1987年,与流域内实际的水利工程建设时间基本一致,两种突变检验方法相结合提高了突变点识别的准确率。气象因素是1953～2011年径流变化的主要驱动因素,但大量水电站的开工与建成导致雅砻江流域径流在1987年发生变化。     

光纤传感器不同布设方式对应变传递的影响分析

为对比不同光纤传感器布设方式对光纤应变传递率的影响,分别建立表贴式和埋入式两种光纤与被测结构的应变传递模型,推导相应的传递系数,通过有限元模型分析验证传递系数的准确性,并基于埋设长度进行敏感性对比分析。结果表明,当埋设长度为1m时,两种方式下光纤中段80%以上区域应变传递率接近1,基体应变均可有效传递至纤芯,两种布设方式均适用于类似结构。光纤两端区域传递率存在不同程度的降低,与埋入式相比,表贴式光纤的两端传递效率低的区域范围更大。敏感性分析表明,随着长度增加,光纤与基体之间的平均应变传递率增高,埋入式始终高于表贴式。因此,对于小型被测基体,布设埋入式光纤更合理;考虑施工及检修,表贴式适合应用于已建大型结构。     

电机生产线噪声故障自动识别

电机振声信号蕴涵着丰富的电机状态信息,因此提出利用电机振声信号实现电机生产线噪声出厂检测。考虑工业现场环境的影响,系统首先采用小波分析对振声信号进行消噪,提取有用信号;再利用小波技术多分辨率的特点,从能量分布角度出发,结合概率论参数区间估计法获得各频段能量区间,对故障电机进行自动识别。系统基于LabVIEW软件平台,实现电机振声信号的实时采集、分析和后处理。现场应用表明,该系统效果良好。     

脂肪醇醚硫酸酯钠盐/α-烯烃磺酸钠二元阴离子液体餐洗剂的配方改进及性能评价

本文以脂肪醇醚硫酸酯钠盐(SLES)和α-烯烃磺酸钠(AOS)两种阴离子表面活性剂所组成的二元餐洗剂配方为基础,通过引入两性离子[椰油酰胺丙基甜菜碱(CAB)]、非离子表面活性剂[椰油二乙醇酰胺(DEA)、脂肪醇聚氧乙烯醚(C_(12)–C_(15)–7EO,C_(10)–7EO和 C_9–C_(11)–7EO)、月桂基氧化胺(AO))对其进行配方改进。对比研究了6个餐洗剂配方(SLES/AOS、SLES/AOS/CAB/AO、SLES/AOS/DEA/AO,SLES/AOS/C_(12)-C_(15)-7EO/AO,SLES/AOS/C_(10)7EO/AO 和SLES/AOS/C_9–C_(11)–7EO/AO)的表面张力、临界胶束浓度(CMC)、清洗能力、发泡性、生物降解性和刺激性,以及温度的影响(17.0,23.0和42.0℃)。结果发现:相对于起始的二元配方,各种非离子表面活性剂的引入可以降低cmc和表面张力,提高餐洗剂配方的清洗能力和发泡性能,而对生物降解性和刺激性影响较小;相对于其他配方,配方6(SLES/AOS/C_9–C_(11)–7EO/AO)展现了最小的cmc和表面张力值,以及最佳的清洗效果;无论低温清洗(17℃)还是正常清洗(42℃),阴离子-非离子表面活性剂的餐洗剂配方(SLES/AOS/ethoxylated alcohols/AO)均具有明显的协同效应,展现出更好的应用性能。     

Sources of enterococci in Idiazábal-type cheese

Enterococci are a ubiquitous group and are natural constituents of the intestinal flora of nearly all animals and humans and can reach high levels in a variety of farmhouse cheeses. The purpose of this study was to determine the origin of the different enterococcal strains present in cheeses at different stages of ripening by typing the enterococci isolated from the raw milk, the cheeses, the cheesemaking environment, and from the faecal matter of the ewes and humans associated with cheese production. The potential presence of vancomycin-resistant enterococci (VRE) at all stages of the process and in the cheeses was also considered. The study was carried out at two separate cheesemaking dairy plants, and samples of the ewes' faeces, the shepherds' and cheesemakers' stools, teat cups, vat, brine, holding tank milk, vat milk, and the cheeses after brining and after 1, 15, and 60 days of ripening were collected. Cheesemaking procedures at the two plants were similar, yet the enterococcal levels and species observed differed at all the sample collection points, though E. faecalis predominated in all the milk and cheese samples. The traceability study performed for the species E. faecalis present at all the sample collection points suggested that the cheesemaker and the cheesemaking equipment were the source of the enterococci in the cheeses, though other possible non-faecal sources remain to be determined. VanC1 and vanC2/C3 enterococcal strains were isolated from the ovine faeces, teat cup, brine, and vat samples at cheesemaking dairy plant A, while only two vanC2/C3 strains were isolated from ovine faeces samples at dairy plant B. No VRE strains were detected in any of the milk or cheese samples.     

Effect of environmental factors and cell physiological state on Pulsed Electric Fields resistance and repair capacity of various strains of Escherichia coli

The aim was to determine the resistance variation of four strains of Escherichia coli to Pulsed Electric Fields (PEF), the role of the sigma factor RpoS in PEF resistance, as well as the influence of several environmental factors and the cell physiological state on the PEF resistance and repair capacity. The rpoS null mutant, E. coli BJ4L1, exhibited decreased PEF resistance as compared with its wild-type parent, BJ4. W3110 and O157:H7 were the most PEF-resistant strains: whereas 2 and more than 3 Log10 cycles of BJ4 and BJ4L1 cells, respectively, were inactivated after 50 pulses at 35 kV/cm, only 0.5 Log10 cycle of inactivation of W3110 and O157:H7 was attained. A different pattern was observed and the resistance variation among strains was largely reduced, when selective recovery media were used. At exponential growth phase, the resistance of the four strains was lower, and more than 4 Log10 cycles of inactivation of all strains tested were attained at 30 kV/cm. Previous heat and cold shock treatments scarcely influenced cell PEF resistance. PEF survival increased with the reduction in water activity of the treatment medium to 0.94: the occurrence of sublethally injured cells was negligible, and less than 1 Log10 cycle of inactivation was attained at 35 kV/cm. PEF-treated cells were sensitive to a subsequent storage at pH 4.0 or in the presence of sorbic acid, attaining a final inactivation of 4-5 Log10 cycles after 24 hour-incubation. In conclusion, the work confirms the role of rpoS in PEF resistance. E. coli strains exhibit large differences in PEF resistance. These differences were less important when cells were recovered under selective conditions. Both resistance variation among strains and occurrence of sublethal damage were noticeably influenced by the environmental factors tested.