支持向量机方法在南京太阳总辐射推算中的应用

利用1981、1996和2001年逐日南京站太阳总辐射和日照时数观测资料,建立了基于支持向量机(support vector machine,SVM)方法的太阳总辐射推算模型,预测了1982、1997和2002年的太阳总辐射,并把推算结果和采用线性的气候学方法所得到的推算结果分别与实测值进行对比。采用线性方法得到的1982、1997和2002年的太阳总辐射预测值与实测值间基于1:1线的决定系数(R~2)分别为0.800、0.859和0.838,均方根误差(RMSE)分别为3.250、2.649和2.925 MJ·m~(-2)·d~(-1)。采用SVM方法得到的1982、1997和2002年的R~2分别为0.894、0.938和0.936,RMSE分别为2.353、1.726和1.804 MJ·m~(-2)·d~(-1)。SVM方法得到的太阳总辐射预测值与实测值之间的误差较小,预测精度高于线性方法,更适用于实际太阳总辐射的计算。     

中国公路运输全要素生产率时空演化及区域竞争——基于Hicks-Moorsteen指数框架

运用Hicks-Moorsteen TFP指数法对中国公路运输业全要素生产率进行测度和演化分析。结果发现：2009~2012年中国公路全要素生产率实现了增长,2013~2015年出现下降。2009年来技术进步推动了东部地区公路运输全要素生产率的增长,而运营效率提升则在推动中西部地区公路运输全要素生产率增长时起到了关键作用。中西部地区公路运输效率增长优于东部地区。东部地区在引领技术进步的同时,应注重公路运输效率的提升;中西部地区应注意加大先进技术的引进。政府和主管部门对中西部公路运输应推出持续性支持政策。     

Oxidized Nitrogen in the Remote Pacific: The Role of Electrical Discharges over the Oceans

Simulations of oxidized nitrogen performed withglobal transport tracer models systematicallyunderestimate the concentrations of total nitrate atremote marine locations in the Mid-Pacific. Higheremission rates in the models of nitrogen oxides( ) from continental sources or alarger influx from the stratosphere do not seem tobe able to account for the shortfall. We are led toconclude that there has to be a substantial sourcelocated in oceanic areas. We speculate that -emission from electrical discharges overthe oceans could be the source we are looking for.Airborne observations of atmospheric concentrationsof oxidized nitrogen and ozone in the remoteatmosphere and observations of nitrate wetdeposition in remote sites are used as additionalconstraints to check the plausibility of thishypothesis. We find that a larger emission of due to lightning activity over the oceansindeed results in a much improved simulation oftotal nitrate in the remote Pacific, particularly inthe Equatorial and Tropical South Pacific and thatsuch a scenario is generally consistent withavailable observations of nitrate wet deposition andatmospheric concentrations of oxidized nitrogen andozone. An alternative hypothesis is that there is ahitherto unknown in situ source of over thePacific Ocean.     

From highly polluted inland city of China to “Lanzhou Blue”: The air-pollution characteristics

Air quality was improved considerably and the so-called "Lanzhou Blue" appeared frequently in Lanzhou due to implementation of some strict emission-control measures in recent years. To better understand whether the concentration of each air pollutant had decreased significantly and then give some suggestions as to urban air-quality improvement in the near future, the variations of the Air Quality Index (AQI) and six criterion air pollutants (PM_2.5, PM₁₀, CO, SO₂, NO₂, and O₃) at five state-controlled monitoring sites of Lanzhou were studied from 2013 to 2016. The AQI, PM_2.5, PM₁₀, and SO₂ gradually decreased from 2013 to 2016, while CO and NO₂ concentrations had slightly increasing trends, especially in urban areas, due to the large number of motor vehicles, which had an annual growth rate of 30.87%. The variations of the air pollutants in the no-domestic-heating season were more significant than those in the domestic-heating season. The increase of ozone concentration for the domestic-heating season at a background station was the most significant among the five monitoring sites. The vehicle-exhaust and ozone pollution was increasingly severe with the rapid increase in the number of motor vehicles. The particulate-matter pollution became slight in the formerly highly polluted Lanzhou City. Some synergetic measures in urban and rural areas of Lanzhou should be taken by the local government in the near future to control fine particulate-matter (PM_2.5) and ozone pollution.     

基于定量化植物防御效应的臭氧通量模型的优化

继SUM06、AOT40之后,基于气孔臭氧累计吸收通量（AFstY）的研究方法被广泛应用于臭氧风险评估中.然而通量模型中的阈值Y并不能很好地代表植物对臭氧的抗氧化能力以及自我修复能力,如何动态模拟植物自身的防御机制对于提高臭氧风险评估的准确性尤为重要.本文基于前人的研究成果探讨如何定量化植物对臭氧的防御效应,运用光合定量方法动态模拟伤害阈值并计算臭氧有效吸收通量,运用SODA模型从气孔吸收和质外体解毒两个方面探讨细胞内抗坏血酸对臭氧原生质膜通量的影响,旨在为臭氧通量模型研究开辟一个新的视角,并为后续的臭氧胁迫效应研究打下基础.     

Impact of Taihu Lake on City Ozone in the Yangtze River Delta

The lake-breeze at Taihu Lake generates a different specific heat capacity between the water body and the surrounding land. Taihu Lake has a significant impact on the atmospheric conditions and the air quality in the Yangtze River Delta. This phenomenon is referred to as the Taihu Lake effect. In this study, two simulations were conducted to determine the impact of the Taihu Lake effect in the reference experiment(R-E) and sensitivity experiments(NO TH). The control simulations demonstrated that the meteorological field and the spatial distribution of ozone(O3) concentrations over Taihu lake obviously changed once the land-use type of water body was substituted by cropland. The surface temperature of Taihu Lake was reduced under the impact of Taihu Lake, and a huge temperature difference caused a strong lake-breeze effect. The results also showed that the difference in the average concentrations of O3 between the R-E and NO TH experiments reached 12 ppbv in most areas of Taihu Lake, all day, on 20 May 2014. During daytime(0800–1600 LST, LST=UTC+8), the influence of the Taihu Lake effect on O3 in the Suzhou region was not significant. However, the influence of the Taihu Lake effect on O3 in the Suzhou region was obvious during nighttime(1800–2400 LST). The larger changes in the physical and chemical processes were horizontal and vertical advections under the influence of the Taihu Lake effect in Taihu Lake.     

全站仪三角高程新方法及精度估算

利用传统三角高程原理和方法推导一种全站仪三角高程测量新方法计算公式。该方法的优点是在观测的过程中不需要量测仪器和棱镜高,从而达到提高精度的目的;并利用误差传播定律进行精度估算和分析,通过与《工程测量规范》中相应的水准闭合差比较,得出在一定条件下该方法可以代替三、四等水准测量。此方法用在施工测量中可以大大地提高工作效率和缩短工程工期。     

基于全站仪交会的变形监测方法的应用研究

介绍了全站仪前方交会和后方交会法相结合的测量方法,方便简捷地解决了测量人员不能进入的水域、高速公路、机场跑道、天线、塔、矿山危险采场等特殊位置的测量问题,并通过对该方法的精度分析,论证了其可行性和有效性,对类似的测量工作提供经验和依据。     

大型刚体精密定位与调整系统的设计和实现

在分析大型刚体构件安装测量技术现状和应用背景的基础上,讨论了大型刚体构件安装自动测量系统的设计方案和运作流程,对某些设计细节作了较为详尽的介绍。     

BHA受压失稳的模型及临界钻压公式

在教学及实践中发现,欧拉压杆模型与底部钻具组合(BHA)受压失稳模型之间存在较大差别,使用欧拉模型计算钻具的临界失稳钻压有很大的局限性。为此,推导了钻具在自重作用下失稳的临界钻压及临界失稳长度公式,以便使公式更符合BHA自身的受力特点,提高计算准确性。