南太湖入湖口蓝藻水华时空分布规律及相关响应因子分析

利用2008年和2009年南太湖蓝藻监测数据,分析研究主要入湖口的蓝藻水华时空分布规律,寻找与蓝藻生长密切相关的响应因子并将其作为蓝藻预警指示指标,为环保部门制定蓝藻应急监测预案、提高蓝藻预警预测的准确性提供科学参考。     

潜艇发射筒保护盖力学性能分析

目的研究艇载发射筒保护盖在深水压力和温度载荷下的力学性能。方法建立保护盖力学载荷和温度载荷模型,采用有限元技术仿真计算保护盖在这些载荷下的形变、应力、温度分布和热结构情况。结果深水压力载荷作用下,保护盖出现的形变大小在0.977~1.47 cm范围内,应力大小在1.22~7.91 MPa范围内。温度载荷下出现的形变大小在0.92~1.38 cm范围内,应力大小在0.272~1.26 MPa范围内。结论两种工况下保护盖最大形变均出现在中部,因此这个部位结构强度需加强,以防其被破坏。     

舰载机机载设备弹射和拦阻冲击试验条件研究

弹射和拦阻冲击试验是舰载机机载设备必要的考核试验之一,而目前相关标准并未明确试验具体量值,且国内缺少试验经验,这会影响试验工作的开展。基于此,从GJB 150.18A—2009规定的阻尼正弦波出发,结合项目研制过程数据,提出波形频率和振幅的确定方法。波形频率可根据类似机型的地面共振试验数据或全机振动模态分析结果确定,这里利用弹性缩比模型地面动响应试验和带通滤波法来预计瞬态波振幅,并说明了阻尼正弦波实施案例和对试验设备冲程的要求。从累积损伤角度出发,认为采用随机振动试验替代弹射和拦阻冲击试验是可行的,而不能采用常规冲击试验进行替代。根据随机振动3σ响应谱和冲击响应谱的对比分析,提出了采用振动功能试验替代弹射和拦阻冲击试验的前提条件——设备安装频率应高于要求值。     

NASA的RIDM风险管理策略及其启示

依据美国国家航空和宇航局(NASA)于2010年4月发布的《基于风险响应的决策方法技术手册》,介绍了NASA采用的基于风险响应的决策方法(RIDM),分析了RIDM风险管理策略的产生背景、运作情况、适用范围、主要特点和成功做法,并对国内开展航天工程项目的风险量化评估以及进行相应领域的风险管理研究提出了若干启示。     

模块化设计在舰载导弹垂直发射装置的应用

分析国内外舰载垂直发射装置模块化设计的基本概况,提高舰载垂直发射装置设计和维修过程中的效能与费用比.解释了舰载垂直发射装置中模块化设计的基本原则和概念,以单元和模块为基本设计元素,介绍了其基本组成,并应用在以热发射、冷发射、电磁弹射为发射方式的舰载垂直发射装置设计上.结合通用化、系列化、适装性、维修性等要求,开展新型舰载垂直发射装置的模块化设计.得出了在役的护卫舰、驱逐舰等舰载垂直发射装置的具体模块组成.模块化设计提高了舰载垂直发射装置研制与维修过程的效能与费用比,降低了研制风险,缩短了研制周期,对新型电磁弹射舰载垂直发射装置的设计提供了参考.     

Cysteine-enhanced reductive degradation of nitrobenzene using nano-sized zero-valent iron by accelerated electron transfer

As an aliphatic amino acid, cysteine (CYS) is diffuse in the living cells of plants and animals. However, little is known of its role in the reactivity of nano-sized zero-valent iron (NZVI) in the degradation of pollutants. This study shows that the introduction of CYS to the NZVI system can help improve the efficiency of reduction, with 30% more efficient degradation and a reaction rate constant nine times higher when nitrobenzene (NB) is used as probe compound. The rates of degradation of NB were positively correlated with the range of concentrations of CYS from 0 to 10 mmol/L. The introduction of CYS increased the maximum concentration of Fe(III) by 12 times and that of Fe(II) by four times in this system. A comparison of systems featuring only CYS or Fe(II) showed that the direct reduction of NB was not the main factor influencing its CYS-stimulated removal. The reduction in the concentration of CYS was accompanied by the generation of cystine (CY, the oxidized form of cysteine), and both eventually became stable. The introduction of CY also enhanced NB degradation due to NZVI, accompanied by the regeneration of CYS. This supports the claim that CYS can accelerate electron transfer from NZVI to NB, thus enhancing the efficiency of degradation of NB.     

Space use in territorial amberwing dragonflies: are residents female maximizers or neighbor minimizers?

Residents of mating territories interact with different categories of conspecifics: females, nonneighbor males, and neighbor males. Interaction with these different types of conspecifics is likely to have different costs and benefits; for example, interactions with females will be beneficial, while interactions with neighbors are more likely to be costly. In this study, we investigated patterns of intrusions and space use in territorial male amberwing dragonflies (Perithemis tenera) to test the idea that residents will adjust their use of space to maximize their beneficial interactions with conspecifics while minimizing their costly interactions with conspecifics. Because territories were arranged linearly around the edge of a pond, each resident had two neighbors, one of which was often closer to the focal resident than the other. Residents experienced more intrusions by neighbors and fewer intrusions by females on the side of their closer neighbor. Residents generally perched on the side of their territory that experienced the fewest intrusions by neighbors and the most intrusions by females, but the pattern was more strongly related to neighbor intrusions than female intrusions. Subsequent to pursuits of neighbors and females, residents tended to shift their perches away from where they pursued neighbors but toward where they pursued females. Nonneighbor intrusions were not affected by neighbor proximity, nor did residents adjust their space use in response to nonneighbor intrusions. Our results suggest that residents do adjust their space use in response to intrusions by conspecifics, that their adjustment depends on the type of conspecific that intruded, and that residents may be using a simple decision rule such as "move away from male intrusions, move closer to female intrusions" to adjust their within-territory space use.Communicated by D. Gwynne     

临海航天发射场设施设备腐蚀控制策略研究

针对临海航天发射场设施设备金属结构腐蚀严重的问题,基于金属腐蚀机理,对发射场设施设备的差异性腐蚀损伤进行了统计和梳理,得出腐蚀成因,并提出腐蚀控制策略和研究方向的建议,为进一步提升我国航天发射场维修保障能力提供理论和技术支撑.     

Pattern formation and individual-based models: The importance of understanding individual-based movement

This paper demonstrates that while pattern formation can stabilize individual-based models of predator–prey systems, the same individual-based models also allow for stabilization by alternate mechanisms, particularly localized consumption or diffusion limitation. The movement rules of the simulation are the critical feature which determines which of these mechanisms stabilizes any particular predator–prey individual-based model. In particular, systems from well-connected subpopulations, in each of which a predator can attack any prey, generally exhibit stabilization by pattern formation. In contrast, when restricted movement within a (sub-)population limits the ability of predators to consume prey, localized consumption or diffusion limitation can stabilize the system. Thus while the conclusions from differential equations on the role of pattern formation for stability may apply to discrete and noisy systems, it will take a detailed understanding of movement and scales of interaction to examine the role of pattern formation in real systems. Additionally, it will be important to link an understanding of both foraging and inter-patch movement, since by analogy to the models, both would be critical for understanding how real systems are stabilized by being discrete and spatial.     

埋设管网系统地震危险性分析方法

埋设管网系统有如下三个特点,即:埋于地基中、在平面内延伸分布范围广、具有生命线工程的重要性,故其抗震设计与地震危险性分析方法也与一般房屋建筑不同。为此,本文提出了一种同时考虑给定地震下地震动场的空间相关性、局部场地条件及地震发生非确定性影响的地震危险性分析方法。本文建议的方法中给定地震下地震动场的确定包括四方面的工作:①确定地震动场的参数,用场内各点之间的相对运动(如相对变形)而不是单点的运动(如加速度);②在频域内确定场内单个点的地震动,以幅值谱与相位谱表示;③用若干个离散点的地震动来描述地震动场;④考虑局部场地的影响。地震动空间相关性与地震发生非确定性同时考虑之间的矛盾问题在本文方法中也得到了处理,采用这一方法的优点是在地震动场中同时考虑了震级、距离及场地的影响,本文提出的方法也可以用于在平面上分布范围较广的其它生命线网络工程。