飞机外场腐蚀损伤检测方法研究

目的研究飞机外场条件下适用的腐蚀损伤检测方法。方法针对某型飞机铝合金和结构钢的腐蚀损伤特点,采用X射线CR(计算机放射成像系统,Computed Radiography,简称CR)、X射线DR(Digital Radiography,简称DR)、红外热波检测等无损检测方法对铝合金和结构钢的典型腐蚀损伤件进行检测,优选及并验证适合用于飞机腐蚀损伤的外场检测方法。结果 X射线CR检测方法可检测铝合金和结构钢单层隐蔽腐蚀损伤和多层隐蔽裂纹,X射线DR检测方法可检测铝合金和结构钢单层/多层隐蔽腐蚀损伤/裂纹,红外热波检测方法只可检测铝合金和结构钢单层隐蔽腐蚀损伤。结论相较于X射线CR和红外热波检测方法,X射线DR成像检测方法能够更可靠、便捷地检测铝合金和结构钢单层/多层结构隐蔽腐蚀/裂纹损伤,更适于飞机结构腐蚀损伤的外场检测。     

强化混凝对二级处理出水中溶解性有机物特性的影响

以沈阳市B污水处理厂二级处理出水为研究对象,采用FeCl3.6H2O作为混凝剂,研究了强化混凝对二级处理出水中溶解性有机物(DOM)的卤代活性和荧光特性的影响.按照DOM在XAD树脂上的吸附特性将其分为5个部分:疏水性有机酸(HPO-A)、疏水性中性有机物(HPO-N)、过渡亲水性有机酸(TPI-A)、过渡亲水性中性有机物(TPI-N)和亲水性有机物(HPI).结果表明,强化混凝(混凝剂投加量为80mg.L-1,pH=5.00)对DOC的去除率为55.3%.强化混凝对HPO-A的去除率最高,而对HPI的去除率最低.强化混凝后,HPO-N的三卤甲烷生成活性(STHMFP)上升,而其他4种DOM组分的STHMFP下降.强化混凝能够有效去除类富里酸荧光物质和具有高环数和高聚合度的稠环类芳香性荧光物质.强化混凝对DOM组分的去除率和DOM组分的荧光强度下降率的相关性不显著.     

Analysis of the selected optical parameters of filters protecting against hazardous infrared radiation

The paper analyses the selected optical parameters of protective optic filters used for protection of the eyes against hazardous radiation within the visible (VIS) and near infrared (NIR) spectrum range. The indexes characterizing transmission and reflection of optic radiation incident on the filter are compared. As it follows from the completed analysis, the newly developed interference filters provide more effective blocking of infrared radiation in comparison with the currently used protective filters.     

基于FLAC3D的盾构隧道施工过程建模影响因素分析

基于FLAC3D对盾构隧道施工过程模拟,研究建模影响因素及其影响程度。首先,综合隧道开挖过程中盾构机前体与岩土层间相互作用的影响因素来模拟隧道开挖过程,确定地表沉降和隧道垂直（Z）方向应力;然后,分别模拟去除其中一种因素后的隧道开挖过程,并求出相应的地表沉降和隧道垂向应力;最后,基于傅里叶变换对各种情况下的地表沉降量和应力应变状况进行比较分析,找出各因素对建模的影响程度,从而为利用FLAC3D进行盾构隧道施工模拟时的影响因子的选择提供参考。研究结果表明：一方面,建模过程中的各种因素对地表沉降的影响大于对隧道Z向压力影响;另一方面,盾构机推进给作业面土体压力、盾尾灌浆延迟于管片拼装造成的暂时对土体支护力不足、盾构机刀盘转动给作业面土体的扭力等因素对模型解算造成的影响最大。     

COMPARISON OF THERMAL SCANNING AND IN SITU TECHNIQUES FOR MONITORING THERMAL DISCHARGES1

ABSTRACT: In situ and remote sensing techniques for measuring thermal plumes are compared for data taken at the Point Beach Nuclear Power Plant on Lake Michigan for five separate occasions. The in situ method employed a boat whose position was determined with a microwave ranging system. Temperatures at the surface and at various depths were measured with fast response thermistor probes. The remote sensing technique utilized an infrared scanner in the 8 to 14 micron range. Comparison of the plumes indicates good agreement with respect to plume configurations, areas within isotherms and centerline temperature decays for all except one occasion, a calm day characterized by no waves, low wind and ambient current velocities. Robable reasons for disagreement under such ambient conditions are discussed. The inherent advantages and disadvantages of each method are discussed in light of the results of the five sets of data. This includes both the data collecting and data analyzing procedures. It is concluded that judicious combination of both methods offers a better picture of thermal plumes than can be obtained by either technique alone.     

Effect of nitrogen/phosphorus concentration on algal organic matter generation of the diatom Nitzschia palea: Total indicators and spectroscopic characterization

Critical algal blooms in great lakes increase the level of algal organic matters(AOMs),significantly altering the composition of natural organic matters(NOMs) in freshwater of lake.This study examined the AOM's characteristics of Nitzschia palea(N.palea),one kind of the predominant diatom and an important biomarker of water quality in the great lakes of China,to investigate the effect of AOMs on the variation of NOMs in lakes and the process of algal energy.Excitation–emission matrix fluorescence(EEM) spectroscopy,synchronous fluorescence(SF) spectroscopy and deconvolution UV–vis(D-UV) spectroscopy were utilized to characterize AOMs to study the effects of nutrient loading on the composition change of AOMs.From results,it was revealed that the phosphorus is the limiting factor for N.palea's growth and the generation of both total organic carbon and amino acids but the nitrogen is more important for the generation of carbohydrates and proteins.EEM spectra revealed differences in the composition of extracellular organic matter and intracellular organic matter.Regardless of the nitrogen and phosphorus concentrations,aromatic proteins and soluble microbial products were the main components,but the nitrogen concentration had a significant impact on their composition.The SF spectra were used to study the AOMs for the first time and identified that the protein-like substances were the major component of AOMs,creating as a result of aromatic group condensation.The D-UV spectra showed carboxylic acid and esters were the main functional groups in the EOMs,with –OCH_3,–SO_2NH_2,–CN,–NH_2,–O– and –COCH_3functional groups substituting into benzene rings.     

热重-红外联用分析纸厂废弃塑料的热解特性

利用热重-红外联用技术(TG-FTIR)对纸厂废弃塑料的热解特性及气体释放特性进行了研究。研究表明,塑料的热解过程主要为2个阶段:第1阶段为氯的析出,第2阶段为碳链断裂。随着升温速率的增加,塑料热解的失重速率有所增加,且析出峰向高温方向移动。使用Doyle积分方法进行活化能计算,发现塑料热解所需要的活化能随着反应程度的增加而有所增大。塑料热解脱氯阶段符合三维扩散,球形对称Jander方程;碳链断裂阶段符合二维扩散,圆柱形对称方程。TG-FTIR结果表明,热解的第1阶段析出产物主要为HCl,第2阶段的热解产物主要为烃类化合物。     

Climate Trends but Little Net Water Supply Shift in One of Canada's Most Water‐Stressed Regions over the Last Century

The southern interior ecoprovince (SIE) of British Columbia, Canada represents the northernmost extent of the great western North American deserts, it is experiencing some of the nation's fastest economic and population growth making it one of Canada's most water‐stressed regions, and it includes two headwater basins of the transboundary (Canada‐US) Columbia River. Statistical trend analyses were performed on 90‐year regional indicator time series for annual conditions in observed temperature, precipitation, and streamflow reflecting the three major SIE river basins: the Thompson, and transboundary Okanagan and Similkameen. Results suggest that regional climate has grown warmer and wetter, but with little net impact on total water supply availability. The outcome might reflect mutual cancellation of increases in precipitation inputs vs. evapotranspiration losses. Conclusions appeared largely insensitive to low‐pass data filtering, Pacific Decadal Oscillation effects, or solar output variability. Ensemble historical global climate model runs over the same time interval support this absence of appreciable trend in regionally integrated annual runoff volume, but a possible mismatch in precipitation results suggests a direction for further study. Overall, while important changes in hydrologic timing and extremes are likely occurring here, there is limited evidence for a net change in overall water supply availability over the last century.     

人工养殖与野生扬子鳄卵中重金属含量分析

以原子吸收分光光度法，测定了人工养殖与野生的扬子鳄卵中Cu、Zn、Cd、Pb等重金属元素的含量，并对上述4种元素的分布状况和差异性进行了探讨。实验表明，人工繁殖卵中重金属元素含量高于野生卵，人工饲养过程中所提供的饮水和饲料中重金属元素含量高于自然界，值得关注和重视。     

基于IRGA通量箱法的草坪夏季晴天CO2净交换量日动态

利用红外气体箱式法(Infrared Gas Analyze,IRGA),于2008年8月晴天对福州市马尼拉草坪(Zoysia matrel-la)的生态系统CO2净交换(NEE)和环境因子进行观测,阐明NEE及其组分的昼夜动态变化特征和影响因子。马尼拉草坪NEE的昼夜变化呈现为单峰型曲线,昼间其变化规律较强,夜间呈波动状态。NEE(取绝对值)最大值出现在10:00,最小值出现在16:00左右。太阳辐射、腔室内空气相对湿度和气温与NEE的相关性均为极显著(p<0.01),太阳辐射、腔室内空气相对湿度和5cm土壤温度共同解释NEE速率昼夜变异的89.30%。太阳辐射和腔室内空气相对湿度是影响草坪生态系统CO2净交换量日动态的主导环境因子;其中,太阳辐射可以单独解释NEE速率昼夜变化的79.70%,腔室内空气相对湿度可以单独解释NEE速率昼夜变化的50.40%;夏季晴天草坪生态系统在日尺度上表现为净吸收,平均CO2净交换速率为-4.11μmol/(m2.s)(负值表示吸收),平均日总通量为-0.18 mol/(m2.d)。