广义形态滤波器在振动信号处理中的应用研究(简报)

为了更好地滤除振动信号中包含的各种噪声干扰,在研究数学形态学基本变换的基础上,提出了一种采用广义形态滤波器来处理旋转机械振动信号的方法。采用广义形态滤波器对振动信号进行降噪处理,无需考虑振动信号的频谱特征,通过开－闭、闭－开组合的广义形态滤波器对振动信号滤波处理后即可消除噪声干扰。仿真试验表明广义形态滤波器能更好地剔除脉冲和降低随机噪声干扰,提高信噪比。广义形态滤波器具有良好的滤波效果,而且算法简单,运算速度快,具有较好的适用价值     

苹果园中2.4 GHz无线信道在不同高度的传播特性

为解决苹果园中无线传感器网络的规划和部署问题,该文研究了苹果成熟时苹果园中2.4GHz无线信道在不同高度的信号衰减和丢包率情况。通过实地试验测量了沿着一列果树由距离地面高度0.50m主干处至3.00m处冠层顶部9个高度下各10个距离点的接收信号强度和丢包率,并对试验数据进行回归分析。研究表明:在不同高度层,2.4GHz信号衰减均符合对数路径损耗模型,模拟的相关系数在0.915～0.983之间;高度1.00～2.25m之间信号衰减均较快。高度大于2.25m时,衰减速度随着高度的增加递减,在冠层顶部高3m处达到最小值。因此,苹果园中天线最宜部署在高约3.00m处的冠层顶部或略高于此,其次为高度大于2.25m的冠层上部且较高的位置。同时,建立了用于预测2.4GHz信号在成熟期果园中的信号衰减模型并用额外的数据进行了验证。结果表明:该模型能较好地预测不同高度处不同传输距离点的接收信号强度,为苹果园中无线传感器网络的应用提供了技术支持。     

污染土壤中硝基苯热脱附研究

以南京黄棕壤和江西红壤为实验土样,通过实验室批量热脱附试验,研究了热脱附温度、热脱附时间、土壤含水率、初始浓度以及土壤类型等对污染土壤中硝基苯热脱附效率的影响。结果表明,当土壤含水率2%,硝基苯初始浓度165.54 mg/kg,脱附温度300℃,脱附时间30 min时,硝基苯的热脱附效率为85.88%,处理后土壤中硝基苯残留浓度为23.37 mg/kg,远低于展览会用地土壤环境质量评价标准（HJ350-2007）（暂行）中的B级标准限值（100 mg/kg）。土壤含水率过高和过低都不利于硝基苯的脱附,当含水率为15% 时,达到了最佳的热脱附效果。硝基苯初始浓度对其脱附效率有较大的影响,随初始浓度的增加,硝基苯脱附效率呈现增大的趋势。而土壤类型对硝基苯热脱附效率的影响较小,在实际修复过程中可以忽略。研究结果可为热脱附法修复硝基苯污染土壤的实际应用提供科学依据。     

活性氧介导的甘蓝型油菜细胞分裂及信号传递机制研究

为了解甘蓝型油菜抗寒机制中活性氧(ROS)的作用机理,探索ROS在甘蓝型冬油菜16NTS309中的产生、分布和信号传递.以16NTS309为材料,结合NBT组织化学染色和组织切片技术,进行O2-亚细胞定位.研究发现,在正常情况下具有较强细胞分裂能力的根尖分生组织、茎尖分生组织、叶原基、叶边缘和愈伤组织细胞中可检测到O2...     

多功能昆虫鸣声信号采集和分析系统及其在褐飞虱鸣声研究中的应用

建立了一套多功能昆虫鸣声信号采集和分析系统(DAASIAS),该套系统界面友好、操作简单、功能齐全,可以对昆虫鸣声信号进行实时采集和各种时频分析,实现了昆虫行为观察与信号分析同步。DAASIAS首先运用在褐飞虱 Nilaparvata lugens  (Stal) 鸣声的采集和分析,结果证明该套系统性能稳定,为昆虫声通讯的深入研究提供了必需的技术平台。     

Effect of relative humidity on thermal degradation of Norway spruce (<Emphasis Type="Italic">Picea abies</Emphasis>) wood

The rate of thermal degradation of wood as a function of the extent of heat-bath treatment was investigated. At both 150°C and 170°C, the rate of degradation increased along with increasing relative humidity in the heating atmosphere. However, up to intermediate relative humidity (in the vicinity of 50%), the higher the temperature, the less was the effect of increasing relative humidity on the degradation rate. Furthermore, the greater the relative humidity, the less was the effect of increasing temperature on the degradation rate. On the other hand, between intermediate relative humidity and water-saturated conditions, the effect of increasing relative humidity on the degradation rate was the same regardless of the temperature, and the effect of increasing temperature on the degradation rate was the same regardless of the relative humidity. In moist conditions, significant thermal degradation occurred at temperatures as low as 150°C.     

利用气象卫星遥感监测土壤含水量

本文介绍了利用极轨气象卫星ＮＯＡＡ／ＡＶＨＲＲ资料遥感监测土壤水分的表观热惯量方法及其原理。同时对土壤含水量与土壤表观热惯量分级之间进行了相关分析,发现二者之间存在显著的正相关关系,并通过回归分析,初步建立了二者关系的数学模型。基于上述数学模型和土壤表观热惯量数字图象,可以生成土壤水分等级图     

Effect of Phenobarbitone Treatment Against Signal Grass (Brachiaria decumbens) Toxicity in Sheep

The effect of phenobarbitone against signal grass (Brachiaria decumbens) toxicity was studied in 26 male crossbred sheep. Grazing on signal grass significantly decreased the concentration of cytochrome P-450 and the activity of drug metabolizing enzymes, viz. aminopyrine-N-demethylase, aniline-4-hydroxylase, UDP- glucuronyltransferase and glutathione-S-transferase in liver and kidneys of affected sheep.Oral administration of phenobarbitone (30 mg/kg body weight) for five consecutive days before grazing on B. decumbens pasture, and thereafter, for three consecutive days every two weeks, resulted in significant increases in hepatic and renal activities of drug-metabolizing enzymes. The induction of drug metabolizing activity in sheep grazing on signal grass group was found to be lower than in animals given phenobarbitone alone. Induction by phenobarbitone provided a degree of protection against the toxic effects of B. decumbens as indicated by the delay in the appearance of signs of toxicity. Furthermore, these were much milder compared to those in the sheep not treated with phenobarbitone. The present study suggests that phenobarbitone-type cytochrome P-450 isoenzyme-induction may increase resistance against signal grass (B. decumbens) toxicity in sheep.     

玉米的厌氧代谢与耐涝性

综述了玉米在低氧和厌氧条件下根系缺氧胁迫的伤害原因和代谢变化,以及厌氧忍而与逃避的适应机制。