温度对烟蚜茧蜂发育、生殖的影响

烟蚜茧蜂发育速率与温度的关系符合逻辑斯蒂曲线,即25℃从卵至羽化所需历期最短(10.67d),30℃发育历期稍有延长(11.6d)。卵至羽化的发育起点温度为3.3℃,有效积温为266.0日度。烟蚜茧蜂雌蜂羽化当天即可产卵,在产卵期的前4天产出总卵量的90%(15-30℃);在6:30-22:30产出总卵量的80%。温度>25℃对烟蚜茧蜂雌蜂的寿命、生殖力,以及对僵蚜体重和羽化率均造成显著的负影响。烟蚜茧蜂雌蜂的寿命、性比、生殖力及僵蚜的体重和羽化率均在20℃时达最佳,结合发育历期的结果,认为该蜂大规模人工繁殖和释放的最佳温度范围是20-25℃。就研究结果在生物防治中的应用也进行了讨论。

Sleeping sites of black-and-white snub-nosed monkeys (Rhinopithecus bieti) at Baima Snow Mountain, China

Data on sleeping sites of a group of black-and-white snub-nosed monkeys Rhinopithecus bieti (Colobinae, Primates) were collected between April-July and September-December 2001 to try to determine the factors affecting site selection at Nanren (99 degrees

A matrix-calculation-based algorithm for numerical change propagation analysis

Engineering changes (ECs) are raised throughout the lifecycle of engineering products. A single change to one component produces knock-on effects on others necessitating additional changes. This change propagation significantly affects the development time and cost and determines the product's success. Predicting and managing such ECs is, thus, essential to companies. Some prediction tools model change propagation by algorithms, whereof a subgroup is numerical. Current numerical change propagation algorithms either do not account for the exclusion of cyclic propagation paths or are based on exhaustive searching methods. This paper presents a new matrix-calculation-based algorithm which can be applied directly to a numerical product model to analyze change propagation and support change prediction. The algorithm applies matrix multiplications on mutations of a given design structure matrix accounting for the exclusion of self-dependences and cyclic propagation paths and delivers the same results as the exhaustive search-based Trail Counting algorithm. Despite its factorial time complexity, the algorithm proves advantageous because of its straightforward matrix-based calculations which avoid exhaustive searching. Thereby, the algorithm can be implemented in established numerical programs such as Microsoft Excel which promise a wider application of the tools within and across companies along with better familiarity, usability, practicality, security, and robustness. © 1988-2012 IEEE.

Closing the Energy Efficiency Gap: A study linking demographics with barriers to adopting energy efficiency measures in the home

This paper presents a study which linked demographic variables with barriers affecting the adoption of domestic energy efficiency measures in large UK cities. The aim was to better understand the 'Energy Efficiency Gap' and improve the effectiveness of future energy efficiency initiatives. The data for this study was collected from 198 general population interviews (1.5-10 min) carried out across multiple locations in Manchester and Cardiff. The demographic variables were statistically linked to the identified barriers using a modified chi-square test of association (first order Rao-Scott corrected to compensate for multiple response data), and the effect size was estimated with an odds-ratio test. The results revealed that strong associations exist between demographics and barriers, specifically for the following variables: sex; marital status; education level; type of dwelling; number of occupants in household; residence (rent/own); and location (Manchester/Cardiff). The results and recommendations were aimed at city policy makers, local councils, and members of the construction/retrofit industry who are all working to improve the energy efficiency of the domestic built environment. © 2012 Elsevier Ltd.

库布齐沙地三年生人工藻结皮发育特征及微生物分布

对库布齐沙地4种三年生不同立地条件下人工藻结皮的发育特征和微生物分布进行研究,结果表明:(1)将荒漠蓝藻接种到沙面,形成的人工藻结皮经过3年的生长和发育,结皮的平均厚度达到2.23—5.36mm,呈现深黑色和灰绿色,结皮盖度大于70%。其中沙柳(Salixcheilophila Schneid.)-羊草(Aneurolepidium chinensis)-藻(algae)结皮(SAA)发育最好、生物量最高,且演替成苔藓结皮。在人工藻结皮区普遍出现沙生植物的拓殖和大量生长,如沙米(Agriphyllum s

Properties of trench defects in InGaN/GaN quantum well structures

The structural and optical properties of trench defects, which are poorly understood yet commonly occurring defects observed on the surfaces of InGaN multiple quantum wells (MQW), are reported. These defects comprise near-circular trenches which enclose areas of MQW which give rise to a red shift in peak photoluminescence emission and a change in cathodoluminescence intensity with respect to the surrounding material. Atomic force microscopy shows that the height of trench-enclosed areas differs from that of the surrounding quantum well structure, and that trenches are unrelated to the commonly observed V-defects in InGaN films, despite being occasionally intersected by them. Cross-sectional electron microscopy analysis of trenches with raised centres suggests that the red shift in the observed cathodoluminescence peak emission may be due to the quantum wells being thicker in the trench-enclosed regions than in the surrounding quantum well area. The mechanism of trench formation and its implication for the control of the emission properties of light-emitting diodes is discussed. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Linear quadratic game and non-cooperative predictive methods for potential application to modelling driver-AFS interactive steering control

This paper is concerned with the modelling of strategic interactions between the human driver and the vehicle active front steering (AFS) controller in a path-following task where the two controllers hold different target paths. The work is aimed at extending the use of mathematical models in representing driver steering behaviour in complicated driving situations. Two game theoretic approaches, namely linear quadratic game and non-cooperative model predictive control (non-cooperative MPC), are used for developing the driver-AFS interactive steering control model. For each approach, the open-loop Nash steering control solution is derived; the influences of the path-following weights, preview and control horizons, driver time delay and arm neuromuscular system (NMS) dynamics are investigated, and the CPU time consumed is recorded. It is found that the two approaches give identical time histories as well as control gains, while the non-cooperative MPC method uses much less CPU time. Specifically, it is observed that the introduction of weight on the integral of vehicle lateral displacement error helps to eliminate the steady-state path-following error; the increase in preview horizon and NMS natural frequency and the decline in time delay and NMS damping ratio improve the path-following accuracy. © 2013 Copyright Taylor and Francis Group, LLC.

控制沙尘暴的植被快速建设技术途径研究——以库布齐沙漠东缘为例

本文根据恢复生态学和景观生态学的基本原理,遵循自然规律和经济规律,依据当地生态条件和地表流沙分布状况,从水土资源优化配置角度出发,结合沙地植物自然分布的趋水性特征,采取以封育措施为主,因地制宜适度造林种草育藻,构建了一种创新的乔灌草藻四为一体的综合快速复合治沙模式,初步实现了脆弱生态系统趋于稳定,生物多样性明显增加,沙尘暴危害被有效遏制的目标。

两湖平原六个湖泊水生植物多样性的比较研究

为了揭示人为干扰对淡水湖泊水生植物多样性的影响 ,本文采用断面法 ,应用全球定位系统 (GPS)技术与地理信息系统 (GIS)技术 ,比较研究了所受干扰强度各不相同的两湖平原的白莲湖、海口湖 (轻度干扰 )、长湖、西凉湖 (较强度干扰 )、大通湖与武山湖 (重度干扰 )水生植物多样性的现状及其 2 0年来的变化 ,并探讨了人为干扰强度与植物多样性丰富程度及丧失程度间的关系。主要结论是 (1) 2 0 0 1年白莲湖、海口湖、长湖、西凉湖、大通湖与武山湖各分布有水生植物 6 9、 6 7、 98、 77、