VIS/NIR spectroscopy,chlorophyll fluorescence,biospeckle and backscattering to evaluate changes in apples subjected to hydrostatic pressures

Chlorophyll fluorescence, VIS/NIR spectroscopy as well as biospeckle and backscattering at 635 nm, 690 nm, 830 nm, and 1060 nm, were used to detect changes in apples stored for 7 d (20 °C), either intact or subjected to high hydrostatic pressures: 100 MPa, 150 MPa and 200 MPa. Biospeckle at 635 nm, 690 nm and 830 nm, and backscattering at 690 nm, 830 nm and 1060 nm showed a high potential for determining changes during storage of intact fruit, while chlorophyll fluorescence, VIS/NIR spectroscopy and backscattering measured at 830 nm, and 1060 nm were appropriate to detect changes in fruit subjected to high hydrostatic pressures. Spectral measurements of apples treated with 150 and 200 MPa showed mainly textural changes and, during post-pressure storage, changes in chemical composition. Decrease in physiological activity and increased rates of enzymatic processes in pressure-treated apples may be responsible for the inability of biospeckle to detect pressure-induced changes.     

高压均质鸡蛋卵黄对猪冷冻精子凋亡的影响

为探究高压均质鸡蛋卵黄对猪冷冻精子凋亡的影响，本试验采集5头健康状态良好的杜洛克公猪精液，以普通鸡蛋卵黄+Tris-柠檬酸-葡萄糖（TCG）冷冻基础稀释液为对照组，以添加高压均质处理的鸡蛋卵黄+Tris-柠檬酸-葡萄糖（TCG）冷冻基础稀释液为试验组；精液冷冻-解冻后观察精子活力、DNA完整性、线粒体膜电位变化、细胞凋亡率、多种Caspase活性；同时利用qRT-PCR检测相关凋亡功能基因的mRNA表达水平，并进行数据统计。结果表明，经高压均质处理后，猪精子冻后活力、活率和顶体完整率显著高于对照组（P<0.05），为87.64%、87.14%和66.61%，较对照组分别提高了12.58%、5.82%和12.48%；线粒体膜电位和DNA完整率显著高于对照组（P<0.05），为0.74和61.76%；精子凋亡水平显著减少（P<0.05），为37.74%；试验组的Caspase-3、Caspase-8和Caspase-9活性为17.15、11.19和15.18，较对照组分别减少了6.17、2.18和3.51（P<0.05）；对照组的Bax、TNF-α、Caspase-9基因表达均明显高于试验组（P<0.05），Bcl-2基因表达量较试验组降低（P>0.05）。综上，高压均质鸡蛋卵黄能提高猪精子冻后质量，促进线粒体功能完整性、降低精子细胞早期凋亡水平和细胞内Caspase活性，同时降低凋亡相关基因mRNA表达量。     

Fine‐scale movement ecology of a freshwater top predator,Eurasian perch (Perca fluviatilis), in response to the abiotic environment over the course of a year

Fine‐scale underwater telemetry affords an unprecedented opportunity to understand how aquatic animals respond to environmental changes. We investigated the movement patterns of an aquatic top predator, Eurasian perch (Perca fluviatilis), using a three‐dimensional acoustic telemetry system installed in Kleiner Döllnsee (25 ha), a small, shallow, mesotrophic natural lake. Adult piscivorous perch (N = 16) were tagged and tracked in the whole lake at a minimum of 9‐s intervals over the course of one year. Perch increased swimming activity with higher water temperature and light intensity. Air pressure, wind speed and lunar phase also explained perch movements, but the effects were substantially smaller compared to temperature and light. Perch showed a strong diel pattern in activity, with farther swimming distances and larger activity spaces during the daytime, compared to the night‐time. To investigate the influence of prey distribution, we sampled the prey fish in both littoral and pelagic zones in both day and night monthly using gill nets. We found that the prey fish underwent diel horizontal migration, using the littoral zone during the day and the pelagic zone during the night. However, perch showed the opposite patterns, suggesting either that the prey fish avoided predation risk or that the horizontal diel migration of perch was driven by other mechanisms. Our results collectively suggest that the movement ecology of piscivorous perch is mainly governed by a foraging motivation as a function of abiotic variables, especially temperature and light.     

基于熵权系数评价模型的烟田灌排工程综合效益分析

针对烟区土壤连作障碍、病虫害、灌溉设施落后等问题,设计不同的灌排处理,对不同处理烤烟增产效益、提质效益和灌排工程的经济效益进行分析,同时引入熵权系数评价模型,对不同灌排工程方案进行优选和评价。结果表明:不同灌排工程均具备较好的增产效益和提质效益(W1除外),微喷灌工程的增产和提质效益总体要优于低压管道;W2~W5灌排工程均具备了经济可行性,不同工程方案以W5经济效益最优,EIRR、ENPV和EBCR值分别达到27.80%、2 894.35%和2.04;本试验中综合效益最佳的灌排方案为微喷灌灌溉结合暗管排水,其中暗管间距为6m,埋深0.8m。     

橡胶树乳管膨压的测定技术及其变化规律

橡胶树胶乳是其韧皮部乳管在受到伤害胁迫后排出的液体细胞质。胶乳的再生和排出均与乳管膨压存在一定关联。本文综述了橡胶树乳管膨压的测定技术及其变化规律的研究结果,发现现有的几种乳管膨压测定技术均存在一定缺憾,对乳管膨压变化规律的研究也因测定方法等的限制不够深入、系统,且未与目前生产上普遍使用的乙烯利刺激割胶制度联系起来;并展望了将植物细胞压力探针技术改进后用于橡胶树乳管膨压测定研究的可能性。     

低矮房屋屋面实测峰值风压分析

通过作者研制的一套可移动实验房及测试系统对近地登陆台风风速和房屋表面风压进行同步观测，研究登陆台风近地边界层风场和低矮房屋风效应.基于0801“浣熊”台风实测数据，分析了实验房屋面角部区域局部峰值负压分布特征和相关性，探讨了角部区域峰值压力时间和空间的平均拆减效应.结果发现,峰值负压系数大于现行规范规定值；并运用广义极值概率模型极值III型对角部测点峰值负压进行极值分析，角部测点峰值负压系数与其实测峰值负压相比要大26.4％.相对良态天气条件，在台风天气作用下低矮房屋屋面角部区域局部易形成较高吸力远大于现行规范推荐值.     

液压机的应用及发展

液压机是一种利用液体静压力来加工金属、塑料、橡胶、木材、粉末等制品的机械。它是利用帕斯卡定律制成的利用液体压强传动的机械和用来传递能量以实现各种工艺的机器。现在液压机不仅可用于锻压成形,也可用于压装、压块、压板、打包和矫正等工艺。比较常见的工艺有压制工艺和压制成形工艺,比如:冲压、锻压、翻边、弯曲、压装、冷挤、校直、粉末冶金、薄板拉深等。     

船舶柴油机工况监视器的设计

为了监测船舱柴油机运行时的各种温度、转速、压力等参数值,设计了一种采用单片机控制的柴油机工况监视系统。整个系统分为主系统模块和从系统模块两部分,主系统安装在机仓内,对柴油机的各种工作参数进行采集处理,并能在液晶显示器上显示出来,当参数异常时能报警。从系统模块安装在驾驶室内,与主系统模块进行无线连接,同步显示柴油机的工况参数并能在参数异常时声光报警。主从系统采用一定的协议规范来进行通信,具有较强的抗干扰能力,从而保障了系统运行的可靠性和稳定性。     

振冲碎石桩在粉砂地基中的应用

以设计为依据,结合工程实际情况,通过碎石桩在粉砂地基中的试桩实验,提出如何控制碎石桩施工时的水压、电流、留振时间等施工要点,以便更好的提高碎石桩的使用效果。