龙凤山站大气CO2浓度2种筛分方法对比研究

针对黑龙江龙凤山区域本底站2009年1月~2011年12月大气CO2在线观测数据,研究基于地面风、日变化等大气本底/非本底数据筛分方法(SWDV)和稳健局部近似回归大气本底/非本底数据筛分方法(REBS)在龙凤山区域本底站的适用性.研究表明:2种筛分方法在春、秋和冬季都能很好反映龙凤山大气CO2浓度的趋势变化及局地源汇对观测CO2浓度的影响,对于高浓度的非本底数据都能够较好的识别,但在夏季使用REBS方法会影响筛分的准确性,不建议在龙凤山区域本底站使用REBS筛分方法.SWDV和REBS法筛分出的本底数据分别占总数据量的30.7%和 58.9%.2种方法均筛分为本底浓度和非本底浓度的数据分别占总数据量的21.5%和32.0%.二者筛分的本底季平均浓度在春季相差最小为(0.1±0.3)×10-6(摩尔比,下同),冬季和秋季次之,在夏季相差最大为(4.2±1.0)×10-6.典型个例分析表明,SWDV法会将白天一些受西南污染气流影响的CO2浓度误筛分为本底浓度,REBS法会将个别在静稳天气条件下受局地影响大的CO2观测值误筛分为本底浓度.夏季局地污染状况可能被植被强烈的光合作用抵消,CO2浓度变化不大,使得REBS误筛分为本底浓度,以及对于一些较低的CO2浓度值,REBS误筛分为非本底浓度,这些因素导致2种筛分方法在夏季本底浓度差别较大.     

A new context-based approach to assess marine mammal behavioral responses to anthropogenic sounds

Acute effects of anthropogenic sounds on marine mammals, such as from military sonars, energy development, and offshore construction, have received considerable international attention from scientists, regulators, and industry. Moreover, there has been increasing recognition and concern about the potential chronic effects of human activities (e.g., shipping). It has been demonstrated that increases in human activity and background noise can alter habitats of marine animals and potentially mask communications for species that rely on sound to mate, feed, avoid predators, and navigate. Without exception, regulatory agencies required to assess and manage the effects of noise on marine mammals have addressed only the acute effects of noise on hearing and behavior. Furthermore, they have relied on a single exposure metric to assess acute effects: the absolute sound level received by the animal. There is compelling evidence that factors other than received sound level, including the activity state of animals exposed to different sounds, the nature and novelty of a sound, and spatial relations between sound source and receiving animals (i.e., the exposure context) strongly affect the probability of a behavioral response. A more comprehensive assessment method is needed that accounts for the fact that multiple contextual factors can affect how animals respond to both acute and chronic noise. We propose a three-part approach. The first includes measurement and evaluation of context-based behavioral responses of marine mammals exposed to various sounds. The second includes new assessment metrics that emphasize relative sound levels (i.e., ratio of signal to background noise and level above hearing threshold). The third considers the effects of chronic and acute noise exposure. All three aspects of sound exposure (context, relative sound level, and chronic noise) mediate behavioral response, and we suggest they be integrated into ecosystem-level management and the spatial planning of human offshore activities.     

β-甘露聚糖酶基因在枯草芽孢杆菌中的克隆及表达

从Bacillus subtilis JNA 3-10中克隆出β-甘露聚糖酶基因成熟肽链编码序列manA1和含信号肽的β-甘露聚糖酶基因manA2,在B.subtilis 168中克隆表达,分别筛选获得高效分泌表达β-甘露聚糖酶的重组菌株BPM1001(pMA5-manA1/B.subtilis 168)和BPM1002(pMA5-manA2/B.subtilis 168),结果表明菌株BPM1002总酶活力是菌株BPM1001的9.65倍,是原始菌株的13.1倍.在基因manA2下游引入His序列克隆出β-甘露聚糖酶基因manA3,获得枯草芽孢杆菌168重组菌株BPM1003.采用Ni-NTA柱纯化重组菌株BPM1003分泌表达的β-甘露聚糖酶,并研究其酶学性质,该酶促反应的最适pH为6.5,最适温度为65℃,在37℃条件下保存一个月酶活力依然保留有77.8%.5 L发酵罐放大实验结果表明魔芋粉对于产β-甘露聚糖酶具有明显的诱导作用,酶活力最高可达2 748.82 U/mL.图9表3参19     

基于HHT的煤岩破裂微震信号分析

微震信号处理是目前研究微震监测技术应用领域中的一个重要课题,应用ESG微震监测系统采集煤巷炮掘过程中产生的煤岩破裂微震信号,针对所采集微震信号具有明显的持续时间短、突变快等特点,选用希尔伯特黄变换(HHT)对其进行处理。HHT包括EMD分解和Hillert变换两部分,微震信号经过EMD自适应分解得出9个IMF分量和一个残余分量,对各IMF分量进行Hillert变换做出Hillert谱,从Hillert谱中得出煤岩破裂微震信号频率响应主要集中在500-800Hz,用边际能量谱加以验证得出Hillert谱在应用中的准确性,为进一步认识煤岩破裂的机理和预测煤岩动力灾害提供了有效的技术途径。     

交通信号倒计时对车速与交通安全的影响

研究交通信号倒计时对自由流车速及交通安全的影响。选择城市道路交叉口,使用雷达测速设备采集进口道自由流车速等数据。运用描述统计、方差分析、列联表等统计方法,进行数据分析。数据显示,仅考虑单因素影响时,交通违法检测设备存在与否对车速均值有显著影响,而绿灯信号倒计时则无显著影响;考虑多因素相互影响时,在有绿灯信号倒计时但无交通违法检测设备的情况下,车辆速度均值会更高,且绿灯倒计时会对超速率产生影响。红灯倒计时对车速离散程度有明显的影响。结果表明,使用绿灯信号倒计时应同时安装交通违法检测设备,红灯倒计时路口应确保充分的绿灯间隔时间。     

Spectrum characteristics analysis of microseismic signals transmitting between coal bedding

This study was performed to investigate the propagation law of microseismic signals transmitting along the direction parallel and vertical to the bedding in the process of coal rock rupture under uniaxial compression. Microseismic signals during the whole process of coal-rock deformation fracture until burst failure was tested by using the coal rock rupture microseismic experimental system. The empirical mode decomposition graphic, Hilbert spectrum and time-frequency spectrum were obtained by using Hilbert-Huang Transform or HHT. Also the microseismic signals transmitting along the direction parallel and vertical to the bedding in the process of coal rock rupture were spectrum comparative analyzed with EMD analysis method. Results show that amplitude and velocity of microseismic signals changed very small along the parallel direction to bedding in the process of propagation, but microseismic signals delayed and amplitude weakened obviously along the vertical direction to bedding. Signal delay and signal attenuation were confirmed that bedding impact on microseismic wave transmitting.     

纳米材料对心血管系统影响的研究进展(Research Progress of the Influences of Nanoscale Materials on the Cardiovascular System)

随着纳米材料生物安全性及纳米毒理学相关研究的深入,纳米尺度物质对心血管系统的潜在危害受到极大关注.论文综述了纳米尺度物质对心血管系统影响的流行病研究和实验研究的最新进展,探讨了纳米尺度物质对心血管系统影响的分子机制,提出了心血管系统是纳米尺度物质所致毒性效应的主要靶点之一的观点,在此基础上对纳米尺度物质对心血管系统影响研究的发展方向进行了展望.     

在数字信号处理中二进制数量化引起的有限字长效应

在数字信号处理中,采用不同的二进制数的表示方法及量化方式,其误差相距甚远.本文首先分析二进制数的不同表示方式是产生有限字长误差的直接原因,然后对三种二进制数的表示方法及两种量化方式做了详细的说明及分析,同时,还利用MATLAB对不同量化方式的误差敏感性进行了分析,并针对具体问题进行了归纳和总结,提出了相应的解决方案.信号处理在林业森林生态信息处理以及林业生产安全信息处理等方面具有重要的意义.     

基于HHT方法的公路运输振动信号时频分析

目的分析具有非线性、非平稳特征的公路运输振动信号的时频信息。方法利用Hilbert-Huang变换算法,在对公路运输的振动信号进行EMD分解的基础上,开展Hilbert谱和各IMF的功率谱密度计算,并与常规的功率谱进行比较。结果基于IMF分量的功率谱可以克服传统Fourier功率谱计算在低频偏低、高频偏高的误差。结论基于HHT的公路运输振动信号时频分析方法是一种有效的运输振动非平稳信号分析手段。     

基于RBF网络的火灾探测信号处理算法研究

本文通过建立火灾探测信号处理的RBF网络模型,并与通常的BP网络模型和期望结果进行对比,结果表明:在进行火灾探测信号处理中,RBF网络可避免BP网络的局部极小以及收敛速度慢等缺点,在精度、训练速度等方面均优于BP网络。该研究为处理火灾探测信号等非结构问题提供了一种行之有效的方法。