沙层水分小尺度地域分异特征 —— 以沙坡头沙区为例

水分是沙漠地区生态环境的限制因子,研究沙漠沙层水分分布规律对在沙区种植人工植物进行固沙有显著指导意义。通过对沙坡头沙区两个典型流动沙丘不同坡向、不同部位以及两个洼地进行采样,研究该区水分平衡与小尺度水分分异特征与规律,结果表明：（1）流动大沙丘顶部沙层水分含量一般在1.00%以下,中部水分含量一般在1.00%—2.00%,底部水分含量一般在2.00%—3.00%,均以薄膜水形式存在。洼地沙层2.0—3.0 m左右深度有饱和重力水甚至地下水出现。（2）流动大沙丘的迎风坡沙层水分高于背风坡,沙丘水分含量均是底部最高,中部次之,顶部最低。（3）沙坡头区沙层水分属于快速入渗型水分正平衡,洼地或平坦地段是大气降水向下入渗的主要渠道。     

Elements of Carbon Balance in Oligotrophic Bogs

Elements of carbon balance of oligotrophic bogs were studied using an example of the landscape profile of the Klyuch River in 1998–2000. Carbon balance was preliminarily calculated taking into account the biological productivity, release of carbon dioxide and methane, and carbon outflow with bog waters. Based on the data obtained on the carbon inflow and outflow, the conclusion was made concerning the progressive peat formation in the region studied.     

县域耕地总量动态平衡规划模式的构建－－以江苏省启东市为例

本文在界定耕地总量动态平衡是由耕地数量、耕地质量和耕地生态环境三者组成的整体平衡的基础之上 ,对耕地总量的评价方法进行了初步研究 ,并以启东市为例 ,构建了耕地生产力总量动态平衡规划模式。     

低压下聚乙烯绝缘层导线火蔓延熔融滴落实验分析

低压导线火蔓延的研究对于飞机和航天器的防火安全具有重要意义。针对镍铬合金线芯、聚乙烯(PE)绝缘层导线火蔓延过程中的熔融滴落现象,在低压舱内开展了不同气压、不同氧气浓度的大量实验研究,获得了导线熔融滴落频率、质量和火蔓延速度,以及不同氧浓度熔融滴落的上下限。结果表明:(1)在熔融滴落过程中,由于滴落会产生向上的动量,从而使火焰在滴落后发生突然的"跳动"现象,火焰高度先增加后降低;(2)滴落上限和滴落下限随着氧浓度的增加而降低,并且可以划分为3个不同的区域:火蔓延仅存区;滴落和火蔓延共存区;无滴落无火蔓延区。滴落上限和滴落下限下降曲线在50%氧浓度、5kPa压力发生会合,此后只有火蔓延而不存在滴落现象。(3)当压力降低时,由于线芯温度增加,线芯传导热量增加,导致绝缘层熔融速率加快,从而使得滴落频率增加,同时液滴的表面张力随着压力的降低而增加,使得低压下液滴的质量变大。     

锅炉蒸汽过热器爆管原因分析及整改措施

针对锅炉过热器管在运行中常见的过热爆管问题 ,从原理及运行工况的角度进行分析 ,并提出了有效的隐患整改措施 ,保证了锅炉的正常运行。     

The relationship between oxygen consumption rate and temperature during coal spontaneous combustion

Spontaneous combustion is a major natural disaster in coal production. In the process of exploring coal self-ignition, a series of hypotheses have been put forward, most scholars agree that the current coal-oxygen compound theory. Oxygen consumption rate reflects the status of coal spontaneous combustion, and it is also one of the parameters necessary for numerical simulation of coal spontaneous combustion. In this paper, a coal heating and oxidation experiment was designed, Experimental device consists of heating and oxidation furnace, gas chromatograph, temperature control and data acquisition systems and other equipment components. Three coal samples whose weight each is 5 g were selected for the study. By experiment, oxygen concentration at the inlet and outlet of temperature oxidation furnace was measured. Oxygen consumption rate is calculated in the heating process of coal according to air flow. In the Cartesian coordinate system, the temperature as abscissa and the oxygen consumption rate for the longitudinal coordinates, drawing the relationship between oxygen consumption rate and temperature plot. And then regression analysis was used to analyze the relationship between oxygen consumption rate and coal temperature during the heating and oxidation process of coal. The results show that the oxygen consumption rate and temperature of coal were linear relationships both before and after the critical temperature when the coal temperature is less than 180 °C. Before the critical temperature oxygen consumption rate is low, however it increases rapidly when coal temperature reaches a critical temperature. The result is important for the prevention and treatment of spontaneous combustion of coal.     

An experimental study on the burning rate of a continuously released n-heptane spill fire on an open water surface

Spill fires are common during oil product storage and transportation after a loss of containment. Since the burning fuel is moving and the fuel depth is quite shallow, the burning rate in a spill fire is different from that of a pool fire with a static burning zone. Unlike pool fires, which have been studied for decades and have well-established correlations for burning rate, research on spill fires is inadequate. In this paper, continuously released n-heptane spill fire experiments were conducted on open water surfaces with varying fuel discharge rates. The pool diameters were measured, and the spill fire burning rates were estimated based on a dynamic balance between fuel supply and combustion. The burning rates in n-heptane pool fires from the literature were reviewed and compared with the estimated burning rates in spill fires of the same dimension. The spill fire burning rate was found to be close to that in a pool fire during the initial burning phase but lower than that in a bulk burning pool fire and that in a “fuel-level-controlled” pool fire. The distinction between the burning rates of spill fires and pool fires is explained by the heat balance analysis of the fuel layer. A model for the spill fire burning rate was proposed accordingly. The results calculated with the presented model are closer to the measured data than those calculated with pool fire models.     

施肥对华北高产区土壤NO-3-N淋失与作物NO-3-N含量及产量的影响

利用4a的平衡施肥定位试验，研究太行山山前平原高产区冬小麦、夏玉米轮作制度下施肥对潮褐土中硝态氮的分布、移动、积累、植株吸收以及作物产量的影响。结果表明，土壤剖面中硝态氮含量与施肥量直接相关，过量施用氮肥使硝态氮在土壤中大量积累并向下层快速移动；氮磷对作物的养分供应存在着既相互促进又相互竞争的关系，施用适量磷肥可以促进小麦、玉米对氮素的吸收，提高作物产量，减少氮素在土壤中积累和淋失，但施磷量太高，由于氮磷之间的竞争作用，作物吸氮量反而下降，从而导致土壤中硝态氮的积累和淋失加剧，施用钾肥抑制了土壤硝态氮积累，促进了两季作物植株对氮素的吸收，从减少土壤硝态氮积累和淋失的角度，提出该区合理的施肥配比为组合N2P2K2，即ρA(N)=200kg hm^-2，ρA(P)=32．5kg hm^-2，ρA(K)=150kg hm^-2。图6参13。     

山谷型垃圾填埋场渗沥液水量计算方法比较研究

山谷型垃圾填埋场渗沥液水量是工程设计中的一个重要基础参数，主要由场内降雨转化为场外地下径流组成。对于场外地下径流，目前国内外尚无成熟的计算方法。作者针对几种常用的水量平衡法，通过实验，验证了每种方法的精度。结果表明，考虑了树冠戴流、表层土调蓄作用等因素的模型具有相当的精度，可以作为场外地下径流的计算模型。     

Modelling the impacts of land-use and drainage density on the water balance of a lowland–floodplain landscape in northeast Germany

This study presents the modelling approach and impact assessment of different strategies for managing wetland water resources and groundwater dynamics of landscapes which are characterised by the hydrological interactions of floodplains and the adjacent lowlands. The assessment of such impacts is based on the analysis of simulation results of complex scenarios of land-use changes and changes of the density of the drainage-network. The method has been applied to the 198 km² Lower Havel River catchment as a typical example of a lowland–floodplain landscape. The model used consists of a coupled soil water and groundwater model, where the latter one is additionally coupled to the surface channel network. Thus, the hydrological processes of the variable saturated soil zone as well as lateral groundwater flow and the interactions between surface water and groundwater are simulated in an integrated manner. The model was validated for several years of significantly different meteorological conditions. The comparison of lateral and vertical water balance components showed the dominance of lateral flow processes and the importance of the interactions between surface water and groundwater for the overall water balance and the hydrological state of that type of landscape.The simulation of land-use change scenarios showed only minor effects of land-use change on the water balance and groundwater recharge. Changes of groundwater recharge were particularly small within the wetland areas being part of the floodplain where interactions between surface water and groundwater are most pronounced. Alterations in vertical groundwater recharge were counter-balanced by the lateral interaction between groundwater and surface water. More significant deviations in groundwater recharge and storage were observed in the more peripheral areas towards the catchment boundaries which are characterised by greater groundwater distance from the surface and less intense of ground water–surface water interactions.However, the simulation results assuming a coarsening of the drainage network density showed the importance of drainage structure and geometry for the water balance: The removal of the artificial draining ditches in the floodplain would result in significant alterations of total groundwater recharge, i.e., less recharge from winter to early summer and an increase of groundwater recharge during summer and autumn. Furthermore the different effects of groundwater recharge alterations on the dynamics of groundwater stages within the wetland areas close to the floodplains compared to the more peripheral areas could be quantified. Finally, it will be discussed that a well-adjusted co-ordination of different management measures is required to reach a sustainable water resources management of such lowland–floodplain landscapes.