发育不良的

Our country firstly put forward such design principle of Qinghai-Tibet railway engineering as "lower temperature actively, reduce the heat into the subsoil, and assure the heat stability of frozen earth for the quality stability of construction", creatively adopt such corresponding measures of frozen earth construction problem as: for the poor frozen earth developing section, line should avoid as possible;for the geology of ice at high temperature and unstable frozen earth zone, the method of bridge instead of subgrade shall be adopted;in subgradeconstruction, such facilities as heat stick, rubble ventilation subgrade , rubble ventilation berm, ventilation pipe subgrade and laying heat preservation board etc shall be adopted to raise the stability of frozen earth subgrade;during the excavation of bridge, culvert , foundation pit and scouring prevention trough, creatively adopt single-tooth knapper and solve the problem of frozen earth excavation;during the construction of bridge and culvert, durable concrete and three-step maintenance method are adopted to assure the outside and inside beauty of structure.

我国在世界上首次提出"主动降温、减少传入地基土的热量、保证多年冻土的热稳定性，从而保证修筑在上面的工程质量的稳定性"的青藏铁路工程设计原则，创造性地采取了解决冻土施工难题的相应对策：对于不良冻土现象发育地段、线路尽量绕避；对于高温极不稳定冻土区的高含冰量地质，采取"以桥代路"的办法；在路基施工中采用了热棒、片石通风路基、片石通风护道、通风管路基、铺设保温板等多项设施，提高冻土路基的稳定性；在桥涵基坑、挡水埝基槽开挖中，创造性地应用了单齿破碎器，解决了冻土开挖难题；在桥涵工程施工中，采用了耐久性混凝土，采用了三步养生法，保证了结构物内实外美。

ResultsCyromazine had a great toxicity to firs t-instar larvae of housefly with LC 50 value of 43.896 mg/L, and showed less toxic actio n to third-instar larvae and adults of housefly, but reduced the pupate, ecl osion, female oviposition and egg hatch.

结果 灭蝇胺对家蝇 1日龄幼虫的 48h的LC5 0 值为 43 。896mg/L ，对 3日龄幼虫和成蝇的毒杀效果较差，但可引起幼虫化蛹率、羽化率以及雌成蝇产卵量和卵孵化率明显下降；阿维菌素对家蝇 1日龄、3日龄幼虫和成蝇表现出较强的急性毒杀作用，其 48hLC5 0 值分别为 0 。162 1mg/L、1.5546mg/L和 0 。2 10 3mg/L ，而对家蝇生长发育无不良影响。

The local factors such as topography, vegetations and soil moisture contents, have great influences on the distribution, ground temperatures, and ground ice contents of permafrost. About 50 km of wetlands have been identified along the China-Russia crude oil pipeline route. In these segments, the surficial deposits consist of peat and humic layers on the top of thick ground-ice, or ice-rich permafrost. The frozen ground engineering geology conditions in wetlands generally are the worst for building and operating the pipeline. The hazardous periglacial processes, such as the widespreadpresence of pingos, icings and frost mounds due to the extensive occurrence of the frost-susceptible soils and ample supplies of surface and ground waters in winter pose significant threats on pipeline operation.

地形地貌单元、植被分布、地表水分条件的变化等局部因素对多年冻土的分布和地下冰的赋存产生重要的影响，管道沿线大约分布有50 km左右的沼泽湿地，其表层为腐殖质土及泥炭层，泥炭层下面分布着含土冰层或地下冰，是管道沿线最差的冻土工程地质地段；由于中俄原油管道沿线水系发育多，冻胀丘、冰椎和冰幔等不良冻土现象广泛分布。

I am sure after a few weeks of adaptation and familiarization I will have no difficulty in functioning on a daily basis in an English speaking society or in participating fully in graduate studies.

在大学的三年的学习生活不仅给予我自身的充实，更重要的是磨练和培养了我较强的自觉能力和严谨，踏实的作风以及不怕困难的精神，对未来充满了信心！

As the first volcanoes erupted, one of the gases that bellowed out was steam.

在第一批火山喷发时，喷出的气体之一就是水蒸汽。