下降了...

During the course of water stress, along with the extension of coercion and the intimidation of the deepening,the Pn of P.euphratica and P.pruinosa experienced three phases:sharp decline-slow, rebound -down and again under moderate and serious stress condition.16 and 24 days later after water stress starting,the reason of Pn drops mainly is the stomatal limit,and 48 days later,primarily is non-sto matal limit.

3在水分胁迫进程中，随着胁迫时间的延长及胁迫程度的加深，中度和重度水分胁迫下胡杨、灰叶胡杨的净光合速率经历了急剧下降-缓慢回升-再下降三个阶段。

In Chapter 2, a nonmonotone trust region method with a line search technique is presented. Unlike traditional trust region methods, our method does not restrict a monotonic decrease of the objective function value at each iteration, but only requires an average of the successive objective function values decreasing.

第二章，我们提出了一类带线搜索的非单调信赖域算法，与传统的信赖域方法不同的是：我们的算法不要求目标函数值在每一步都有充分下降，而是要求目标函数的连续平均值充分下降。

The contents of Chla and Car were sensitive to low temperature stress, it seems that they were vulnerable to low temperature stress and partly decomposed. Relatively, the content of Chlb changed little. The ratio of Chla/b had positive linear correlation with temperature, which meant the photosynthetic ability of podocarpus fleuryi Hickel seedlings declined under winter low temperature stress.

叶片中叶绿素a和类胡萝卜素含量对低温胁迫反应较为敏感，容易遭受低温胁迫而部分地分解破坏，含量下降，而叶绿素b则相对变化较小，Chla／b值呈现与温度的线性正相关，显示了长叶竹柏幼苗在冬季低温胁迫下光合能力的下降情况。

The critical wetting surface tensions and the polar component of surface tensions decrease with the increasing of lengths of hydrocarbon chains of derivatives.

得到了以下规律：颜料的临界润湿表面张力随着铜酞菁衍生物碳氢链长度的改变均有不同程度的下降；颜料的表面自由能、表面自由能的色散成分变化不大，而极性成分下降比较明显。

Once up on top, be careful the euphoria of the summit doesn't get in the way of precautions for the rappel down.

只要你上攀便须要下降；登顶之后，小心登顶的陶醉而忽略了安全的下降。

This process will no doubt cause population declines in other species, just as it has in the salamander species.

这一过程无疑会导致其他物种的种群数量下降，正如它已导致了蝾螈物种的数量下降那样。

In the study of infrared radiation character, different species of tourmaline and Draviteoccurring in pegmatites from Hebei that are different in granularity and heattreatmenttemperature are chose for infrared radiation ratio testing. The result shows:The infraredradiation ratio of tourmaline powder is above 0.80 when the surrounding temperature is 20℃and the testing temperature is below 100℃;Schorl has a close infrared radiation ratio to Dravite,which is higher than Elbaite;No matter to Dravite or Schorl, as the content of ferric oxideincreases, the infrared radiation ratio decreases;tourmaline's size is smaller, its infraredradiation ratio is higher;after tourmaline is heat-treated under 800℃, its infrared radiation ratiodeclines;Dravite heat-treated at 800℃ has the highest infrared radiation ratio, 0.90;andDravite's structure suffers from destruction above 900℃ heattreatment, so its infrared radiationratio goes down.

在红外辐射特性的研究中，本文选择了不同种属电气石、不同粒度和不同热处理温度河北伟晶岩镁电气石进行红外发射率的测试，结果表明：在环境温度为20℃、测试温度为100℃下，电气石粉体红外发射率均在0.80以上；铁、镁电气石红外发射率相近，且大于锂电气石；不论在铁电气石还是在镁电气石中，随氧化铁质量分数的增加，红外辐射率下降；电气石粒径越小，红外发射率越高；电气石在低于800℃以下温度的热处理后，红外发射率下降，800℃热处理电气石红外发射率最高，为0.90，900℃以上电气石结构遭到破坏，红外发射率降低。

The global macroeconomic slowdown, but also resulted in a decline in power generation, coastal coal traffic reduction, resulting in sharp decline in coal sea freight.

全球宏观经济放缓，但也导致了发电，减少沿海煤炭运输的下降，在煤海运费大幅下降造成的。

Undesirable structure and tree species simpleness etc are main problem in existing urban forest, influence urban forest effective exert its zoological function(2) urban forest landscape indexes show: urban forest fragment increased form 1985 to 1995, and decreased form 1995 to 2007, but as a whole, Beijing urban forest fragment is degressive, especially woodland and spinney land.

2在研究时段内北京市城市森林景观指数变化明显，从1985-1995年间破碎化程度增加，而1995-2007年间下降，1985-2007年总体呈下降趋势，其中有林地和灌木林两种主要城市森林用地类型的变化剧烈；城市森林尤其是有林地用地受到人为干扰影响强烈，斑块日益简单化，主要类型城市森林间相互转化现象严重，说明北京市城市森林在研究时段内发生了很大变化。

A centrifugal governor rang an alarm bell if gyro rpm fell too low, and support sprag wheels on either side were automatically lowered to prevent the car falling over.

1离心调速器响了一警钟，如果陀螺转速下降过低，并支持sprag轮子，任何一方被自动降低，以防止汽车下降。

Shop assistant: Please check at the door.

店员：请您到门口柜台交费。

In the end, transportation of PAHs in the environmental matrix was preliminarily investigated and discussed according to PAHs data of soils and sediments from a certain region in Shanghai. The result indicated that there are two or more pathways on PAHs transportation in the environmental matrix.

最后，对上海特定地区内PAHs在环境介质中的迁移径途进行了分析讨论，结果表明上海市土壤和沉积物等环境介质中PAHs的迁移存在多种途径。