Second harmonic generation from a ferroelectric film

We derive an expression for transmittivity (T_SHG) of second harmonic generation (SHG) signals from a ferroelectric (FE) film. Intensities of up and down fields in the medium are investigated in relation to T_SHG. The derivations are made based on undepletion of input fields and nonlinear wave equation derived from the Maxwell equations. We present two cases: film without mirrors and with partial mirrors. Expressions for the newly derived nonlinear susceptibility coefficients of SHG for real crystal symmetry [J. Opt. Soc. Am. B 19 (2002) 2007] are used to get more realistic results. Variations in T_SHG with respect to film thickness are illustrated.     

Susceptibility of Listeria monocytogenes strains to disinfectants and chlorinated alkaline cleaners at cold temperatures

Minimal inhibitory concentration (MIC), suspension and biofilm tests were used in evaluating the disinfecting efficacy of eight commercially available disinfectants and four chlorinated alkaline cleaners against 10 strains of Listeria monocytogenes at refrigerated temperatures. The adaptive response and cross-adaptation of L. monocytogenes to the disinfectants and chlorinated alkaline cleaners were investigated. The bactericidal components in the agents used were chlorine, quaternary ammonium compound (QAC), peracetic acid, ethanol and isopropanol. With some exceptions the disinfectants were efficient against the L. monocytogenes strains. One alkaline hypochlorite containing disinfectant was not efficient in the suspension and MIC tests at the lowest concentration recommended by the manufacturer. The chlorinated alkaline cleaners were effective against L. monocytogenes. A QAC-based disinfectant was found to be the least-effective agent on both glass bead-blasted polyethylene and stainless-steel surfaces. Adaptive and cross-adaptive responses of L. monocytogenes strains were observed towards the QAC-based agent, but over 2-fold increases to other agents were not observed. These results suggest that the adaptive responses of L. monocytogenes to disinfectants or chlorinated alkaline cleaners are of a minor concern.     

初生空化与液体抗拉强度的关系

自1983年开始以液体的抗拉强度作为其空化临界压强研究初生空化的比尺效应以来,该方法已得到进一步的应用和完善。本文就研究中遇到的一些问题,如关于空化灵敏度仪的校正,“零抗拉强度”的概念,试验设备中液体抗拉强度的动态变化以及在空化试验中使用该方法的技术和意义等作详细的阐述。     

阀门组件老化敏感点预警值的确定及老化缓解对策

对大亚湾核电站死管段相关的核一级电动阀阀门组件的机械老化机理进行了讨论,并针对阀门组件的失效模式,对老化敏感点进行了识别,选出最重要的老化敏感点进行分析讨论,确定其预警值,最后提出并归纳了一些适合大亚湾核电站实际情况的老化缓解对策。     

Quantitative analysis of time-course development of motion sickness caused by in-vehicle video watching

It has been common and popular to watch videos in moving vehicles. An important issue in developing comfortable in-vehicle video watching systems is to understand how passengers get motion sickness. With this in mind, the goals of this paper are (1) to introduce an experimental protocol and a statistical analysis procedure for quantitatively evaluating how motion-sickness is developed during car-driving, and (2) to demonstrate their practical usefulness with a working experimental study. In the experimental protocol, motion sickness was induced to subjects by requiring them to watch an in-vehicle video during 15-min driving, and the time-course development of motion sickness was recorded by asking subjects to evaluate their degree of motion sickness every one minute. A main difficulty in analyzing data from these studies is how to incorporate the individual difference in motion-sickness susceptibility. Since susceptibilities are markedly different among subjects, within-subject design experiments are preferred. However, it is practically difficult to conduct complete set of trials because subjects who are not willing to continue experiment (due to heavy motion sickness) should be able to withdraw from the subsequent series of trials in accordance with ethical requirement. To cope with this incomplete data issue, we introduce a statistical data analysis procedure that enables to estimate and impute missing entries in the within-subject design table. Using a working example, we demonstrated that the protocol and the procedure are useful for quantitative assessment of the time-course motion sickness development. We conducted an in-vehicle motion-sickness study with 31 subjects, where the time-course motion sickness developments of video-watching, book-reading, and normal riding conditions were compared. The results indicate that video-watching brings on 2.7 times more severe motion sickness than normal riding, but 25% less severe than book-reading.     

Efficacy of ozone against adults and immature stages of phosphine susceptible and resistant strains of Rhyzopertha dominica

Ozone was investigated as a potential alternative to control phosphine resistant strains of the lesser grain borer, Rhyzopertha dominica (F.). The efficacy of 0.21 and 0.42 g/m³ concentrations of ozone against one phosphine-susceptible laboratory and two phosphine-resistant field strains of R. dominica was evaluated. Vials holding 20 adults with 0 and 10 g of wheat were exposed to each ozone concentration for up to 24 h to estimate lethal doses required for 50 (LD₅₀) and 99% (LD₉₉) mortality. After ozone exposure, mortality was assessed 5 d later. There were no significant differences between LD₅₀ values of the samples exposed to 0.21 and 0.42 g/m³, regardless of strains and presence or absence of wheat. The small amount of wheat (10 g) affected efficacy at 0.21 g/m³, but showed a non-significant effect at 0.42 g/m³. Ozone tends to react with active sites on the surface of wheat kernels prior to reaching an effective lethal concentration for insects. High ozone concentration in the supply air reduced the time to saturate all active sites and ensured that lethal levels of free ozone were available to kill insects.Ozone successfully suppressed the adult progeny production for all tested strains. Emergence of adults from eggs of all three strains was reduced by 96.3–100% only after 72 h exposure to an ozone concentration of 0.42 g/m³. At the same ozone concentration, emergence of adults from young and old larvae was reduced by 97.1–99.7% after a 24 to 34 h exposure. However, reduction in emergence of adults from ozone exposed pupae at 10 h varied among the strains and ranged from 32.8 to 96.6%. After 2 and 6 h of exposure the reduction in emergence of adults from pupae ranged from 19.6 to 76.5%.     

高氡暴露地区人群中代谢酶GSTM1基因多态性与肺癌易感性关系的研究

本文采用病例-对照研究方法,以多重聚合酶链反应扩增技术,对高氡暴露地区53例肺癌患者和72例对照人员进行了代谢酶GSTM1基因多态性检测,并分析了不同人群中该基因多态性与肺癌发病风险的关系,以探讨高氡暴露地区人群中GSTM1基因多态性与肺癌易感性的关系。结果表明,GSTM1基因功能型和缺陷型在肺癌组分布分别是38.9%、64.1%,在对照组分布分别为43.1%、56.9%。GSTM1基因缺陷型的肺癌发病风险为1.35倍(95%可信限0.652～2.81),有效剂量<50mSv的人群中GSTM1基因缺陷型的肺癌发病风险是功能型的1.14倍(95%可信限0.198～6.60)。从以上结果可以看出,GSTM1基因功能型在肺癌组的分布频率低于对照组的分布频率,而缺陷型在肺癌组的分布频率高于对照组的分布频率;GSTM1基因缺陷型使肺癌的发病风险有增高的趋势,但未见显著性差异。     

Sasobit对沥青感温性能的影响分析

通过对Sasobit与沥青配伍性的研究,表明Sasobit与沥青之间的混合时间、混合温度以及混合方法对其性能稳定性影响不大,故采用在1300C下人工搅拌15min的方法进行Sasobit沥青的制备。利用不同剂量的Sasobit沥青在不同温度下的针入度、粘度和软化点等性能指标的测试结果,计算了Sasobit沥青的感温性能指标：针入度指数、粘温指数、针入度粘度指数和针入度软化点指数。由计算结果可知,在沥青中添加不同剂量的Sasobit会提高其在不同温度区域内的感温性能,且各个感温性能指标之间有很好的相关性,根据其感温性能的变化可以确定在沥青中添加3％Sasobit最为合适。     

土壤磁性在石油天然气早期勘探中的应用

基于“氧化还原灶”原理的非地震石油天然气的一般物化探方法,常不易于区分油气及相关因素形成的次生异常和由成岩成土作用形成的原生异常,以及测量的结果随昼夜,年季节,年份的变化,直接提取油气因素导致异常信息,开发可记录的油气作用随时间积累的勘探指标,将有可能成为非地震油气勘探的研究前沿课题,近年来,油气田上方的微磁异常和土壤磁化率异常的研究有了重要的进展,异常的含铁矿物与油气渗漏的烃类物质,氧化还原细菌     

Correlating reaction time and nausea measures with traditional measures of cybersickness

We provoked cybersickness in participants by immersing them in one of two virtual roller coaster rides using a head-mounted display. As simulation technology is often used in training, our main intention was to examine the effect of the experience on their cognitive function. Participant reaction times before and after the experience were measured by averaging their response time to a visual stimulus over a number of trials. We measured a significant reduction in response time before and after the virtual experience. We also examined the changing state of nausea experienced by participants using some simple nausea measures. These included a repeated nausea rating recorded by participants at two-minute intervals. At the completion of the experience, we averaged these ratings to create a standard nausea score. As participants could decide to stop the experience at any time, we also recorded the voluntary duration of the experience. We correlated our measures with two traditional simulator sickness measures, namely the Motion Sickness Susceptibility Questionnaire (MSSQ) and Motion Sickness Assessment Questionnaire (MSAQ). The standard nausea score provided a simple measure of nausea that could be collected at regular intervals with minimal interference to the immersive experience, and was significantly correlated with both the MSSQ and MSAQ scores.