小麦条锈菌的紫外诱变处理及致病性变异体的筛选

用紫外线以不同时间处理小麦条锈菌水源致病类型1-4、条中29-3、条中23-2,当夏孢子致死率达90%左右时,确定为最适诱变时间分别为12、8、5min.以紫外线12min处理水源致病类型1时,经6批次筛选未获得突变体.以8 min处理条中29-3,得到在Hybrid46上表现3型的菌系,在尤皮Ⅱ号上表现4型的菌系和在阿夫上表现2型的菌系,分别命名Hybrid46菌系、尤Ⅱ菌系和阿夫菌系,三菌系经4代转接该品种,最后获得2个稳定的突变菌系,包括毒性突变产生的尤Ⅱ菌系和非毒性突变产生的阿夫菌系.以5 min处理条中23-2得到两个突变菌系：在尤皮Ⅱ号上表现3型的菌系和在水源11上表现2型的菌系,分别命名为尤Ⅱ-23菌系和水源11菌系,其中尤Ⅱ-23菌系经4次转接仍保持毒性.     

利用云量估算南京地区日总辐射方法的研究

为填补实测太阳辐射资料的空缺,利用南京地区1961年-2010年常规气象资料建立了由总云量反演逐日太阳辐射的模型,并对南京地区近50年来太阳总辐射的变化特征进行了分析.首先采用南京气象站1961年-2000年实测太阳总辐射数据借助粒子群优化算法确定了模型参数,然后利用2001年-2010年数据对模型效果进行了检验.结果表明:辐射模型模拟值与实测值拟合程度较好,Nash-Sutcliffe效率系数(NSE)、均方根误差(RMSE)和皮尔逊相关系数(r)分别为0.74、48.6W/m2和0.8.南京地区太阳总辐射受云量影响较大,其年内变化趋势基本与晴空辐射相吻合,但又存在差异,这主要是与梅雨季节有关.     

关于铀、钚和铀核裂变产物的若干问题——兼谈2011年福岛核事故泄露的放射性物质

文章以日本福岛核电站7级核事故两周年为契机和切入口,主要涉及:常用的核裂变材料———铀;铀原子核裂变("两分裂")产物;另一种核裂变材料———钚;福岛核电站核事故后外泄的放射性物质等。文章还以福岛核电站7级核事故为例,立足于传播基础核知识、核能知识及有关新信息,文章以铀、钚及其裂变为中心,对核事故与核污染等做了些介绍、说明,意在让更多的人科学地认知相关事件与现象。     

Information recall of younger and older skilled athletes: The role of display complexity,attentional resources and visual exposure duration

This study was concerned with the interactive role of experience of athletic skill with other relevant environmental variables (display complexity, attentional resources, exposure time of stimuli) on perception (recall) of structured handball game situations. Nineteen experienced (older) and 19 less experienced (younger) handball players were assigned randomly either to ball‐bouncing (diverted attention) or to calm seated (focused attention) conditions. In each of the two conditions, the subjects were exposed to a total of 36 slides containing 2–3, 5–6 and 8–10 players. Eighteen slides were exposed for 0.5 s and 18 for 1.0 s. All the slides contained structured defence and offence situations. Recall scores were subjected to repeated‐measures ANOVA using attention condition and age as between‐subject factors and task complexity and exposure duration as within‐subject factors. The results showed that the recall of less experienced players deteriorated more than the recall of more experienced players following exposure to complex displays (≥ 8 players) while engaging in a secondary task (bouncing). The findings suggest that research paradigms should be applied in the field of sport which share both ecological validity and a potential to discover the cognitive substrates underlying experience and age in skilled motor performance.     

从极端天气事件演变规律和地理环境看昆明长水机场低能见天气成因及安全运行措施

昆明长水国际机场因地理环境特殊造成大雾等天气致使低能见度天气发生频率相对偏多。本课题从地理环境分析出长水国际机场大雾天气的成因,对比分析了大雾造成昆明长水国际机场和原巫家坝机场低能见度天气情况,得出长水国际机场大雾天气远多于原巫家坝机场的结论,最后就低能见度天气条件下机场、管制部门和航空公司等多家单位确保航班安全运行的措施和应对航班大面积不正常情况下快速恢复航行提出建议。     

红外传感式延时光控路灯

本文利用红外热辐射探测传感器与光控元件设计出一种节能,方便的延时路灯.文章阐述了其工作原理及设计构思,并给出了具体电路及有关参数据供读者参考.     

人工紫外线照射对家兔几项生理指标,心电图及眼睛的影响

采用30瓦水银石英紫外灯照射健康家兔18小时,测定了紫外线对家兔几项生理指标、心电图及眼睛的影响。结果,兔体温、红细胞渗透脆性不受影响;心电图变化不明显,呼吸数、红细胞数、血红蛋白含量、白细胞数在照射后均有增加(P>0.05),但是,白细胞数在照射6小时后显著增加(0.01相似文献   

对辐射场通过自旋相互作用发射光子的探讨

本文对辐射场依赖自旋相互作用发射光子的理论进行了深入探讨,作为特例计算出依赖自旋相互作用氢原子2S态的寿命,从而说明在辐射量子理论中忽略电子自旋相互作用的原因。     

Children’s Reading Comprehension and Oral Reading Fluency in Easy Text

This study explored third-graders’ oral reading fluency (ORF) in easy text in relation to their third- and fourth-grade reading comprehension. It also examined the children’s performance on two different measures of text exposure, a self-report questionnaire and a title-recognition test. Although third-graders’ ORF related significantly to their reading comprehension, oral language comprehension accounted for most of the variance in reading comprehension, whereas single word reading speed accounted for most of the variance in ORF. Third-grade reading comprehension and ORF each predicted unique variance in children’s scores on a fourth-grade state-mandated reading comprehension assessment. Scores on the self-report questionnaire correlated significantly with third-grade ORF and fourth-grade reading; the self-report accounted for reliable variance in ORF even with all of the other reading ability variables entered first. Results are consistent with the viewpoint that text exposure affects reading fluency. They also demonstrate that ORF is a valuable predictor of middle-elementary children’s reading comprehension, even when the ORF measure employs very easy text in which children achieve near-perfect word accuracy.     

二能级原子在高斯驻波中所受辐射力

计算在高斯分布的弱电磁驻波中沿Ｚ轴方向运动的二能级原子所受的辐射力，并讨论近共振情况下高斯驻波对原子的作用．说明下失谐（△＜０）时，高斯驻波有可能冷却和囚禁二能级原子．