大学英语课堂教学的创新与实践

当今社会对大学生的英语水平及综合应用能力提出了新的更高要求,大学英语教学也因此面临新的挑战。作者根据自己的教学实践,阐述了在大学英语教学中的一些做法与体会,期望起到抛砖引玉的作用。     

Cross‐resistance,mode of inheritance and stability of resistance to emamectin in Spodoptera litura (Lepidoptera: Noctuidae)

BACKGROUND: Spodoptera litura (F.) is a cosmopolitan pest that has developed resistance to several insecticides. The aim of the present study was to establish whether an emamectin‐selected (Ema‐SEL) population could render cross‐resistance to other insecticides, and to investigate the genetics of resistance. RESULTS: Bioassays at G₁ gave resistance ratios (RRs) of 80‐, 2980‐, 3050‐ and 2800‐fold for emamectin, abamectin, indoxacarb and acetamiprid, respectively, compared with a laboratory susceptible population Lab‐PK. After three rounds of selection, resistance to emamectin in Ema‐SEL increased significantly, with RRs of 730‐fold and 13‐fold compared with the Lab‐PK and unselected (UNSEL) population respectively. Further studies revealed that three generations were required for a tenfold increase in resistance to emamectin. Resistance to abamectin, indoxacarb, acetamiprid and emamectin in UNSEL declined significantly compared with the field population at G₁. Furthermore, selection with emamectin reduced resistance to abamectin, indoxacarb and acetamiprid on a par with UNSEL. Crosses between Ema‐SEL and Lab‐PK indicated autosomal and incomplete dominance of resistance. A direct test of a monogenic model and Land's method suggested that resistance to emamectin was controlled by more than one locus. CONCLUSION: Instability of resistance and lack of cross‐resistance to other insecticides suggest that insecticides with different modes of action should be recommended to reduce emamectin selection pressure. Copyright © 2010 Society of Chemical Industry     

轻型门式刚架结构中关于稳定分析问题的探讨

针对现行《门式刚架轻型房屋钢结构技术规程》（CECS 102:2002）中关于稳定分析的部分条款,通过大量系统的有限元分析,指出上述条款中存在的问题,并提出改进的建议：1）对单跨门式刚架变截面柱计算长度系数的取值提出了修正,并扩充了取值范围;2）对带摇摆柱门式刚架变截面柱计算长度放大系数的公式提出了修正;3）对工字形截面构件腹板有效宽度系数的公式提出了修正;4）提出了新的风吸力下冷弯薄壁檩条稳定承载力计算公式.以上工作为《上海市轻型钢结构技术规程》的修订提供了理论依据.     

2种不同形状诱芯田间诱蛾效果比较

在田间比较了双孔扁垫柱型诱芯和反口钟型长效诱芯不同使用期对小菜蛾的诱集效果和持效期。结果表明,随着使用时间的延长,2种诱芯的诱蛾效果均逐步下降,前期双孔扁垫柱型诱芯诱蛾效果好于反口钟型长效诱芯,后期二者差异不显著。     

棉花穴盘育苗移栽高产示范试验

采用对比设计,研究了棉花穴盘育苗移栽栽培方式与地膜直播栽培方式（CK）对棉花生长和产量的影响。结果表明：棉花穴盘育苗移栽栽培方式的棉花生育期较CK长12 d,虽然全生育期整齐度和苗期生长势较CK差,但花期和絮期的生长势好于CK,单株成铃数明显增多,增产显著。棉花穴盘育苗移栽栽培方式可以在生产上大面积推广应用。     

高简并引物小温度范围不规则降落PCR在庞大基因家族扩增中的应用（摘要）

[目的]探讨了高简并性引物扩增庞大基因家族基因的特殊方法。[方法]采用常规高简并引物对鲤鱼基因组DNA分析进行了常规PCR扩增、常规降落PCR扩增以及优化后的小温度范围不规则跳跃降落PCR扩增。[结果]采用PCR仅得1条明显条带,得到的基因较少;采用常规降落PCR法仅得到弥散性扩增,无明显条带出现;而采用小温度范围的不规则跳跃降落PCR则得到了得到了3条明显条带和多个基因,扩增结果理想。[结论]为庞大基因家族扩增条件中的优化与选择提供了理论依据。     

六茜素注射液的亚慢性毒性试验

为了研究六茜素注射液的安全性,进行了六茜素注射液的亚慢性毒性试验。试验每天给大白鼠灌服六茜素注射液80、160、320 mg/kg,对各组大白鼠的体重变化、脏器系数、血液生理生化指标及心脏、肝脏、脾脏、肾脏、胸腺等脏器病理变化进行了测定和分析。结果表明,试验组大白鼠的各脏器无明显肉眼可见剖检病变;试验组大白鼠的各脏器系数与对照组差异不显著(P>0.05);320 mg/kg剂量组大白鼠的肝脏和肾脏器官出现轻微的病理变化。结果说明,六茜素注射液毒性低,可以安全用于动物。     

Influence on new tunnel mechanics behaviorinduced by construction about adjacent spacing

This paper takes Chongqing Two-River Tunnel as the research background, based on the system for structure and surrounding rockmass of the highway tunnel, conducts a three-dimension model test about forked tunnel with different altitude to study new tunnel’s mechanics behavior induced by construction, and uses numerical simulation to analyze model domain. The results show that the displacement on new tunnel’s left hance is larger than the displacement on its right hance. Left hance displacement is larger than hance displacement of the single tunnel, and the right hance displacement is less than hance displacement of the single tunnel. The trend of hance displacement and crown settlement with different adjacent spacing is got. Normalizing hance displacement and crown settlement of model test, the relation between displacement and adjacent spacing is disclosed. The hance displacement and crown settlement gained by numerical simulation is close to the converted result of model test, which indicates that the model test data is consistent with the result of numerical simulation.     

注射用硫酸链霉素细菌内毒素检查法的探讨

按照《中国兽药典》二○○五年版一部[1]中注射用硫酸链霉素细菌内毒素检查法对样品复核检验,试验表明该方法是可行的;并与《美国药典》进行了比较,结果说明《中国兽药典》注射用硫酸链霉素细菌内毒素检查法对细菌内毒素的限值表达比《美国药典》29版[2]更合理、更科学。     

吡喹酮注射剂含量测定方法比较

采用两种不同的色谱条件测定吡喹酮注射剂中吡喹酮的含量,色谱柱为迪马DiamonsilC18（4．6mm×250mm,5μm）柱,流动相为甲醇-水及乙腈-水,检测波长为263nm及210nm,流速1mL/min。结果显示,在两个不同的检测范围内,线性关系均良好（分别为r=0．9998和r=0．9996）,吡喹酮的平均回收率为100．38％和99．90％,RSD=1．13％和1．1％（n=9）。两种方法简便易行,精密度、回收率、重现性均符合要求。结果表明,两种方法均可用于吡喹酮注射剂的含量测定。