Nitrate leaching during establishment of willow (Salix viminalis) on two soil types and at two fertilization levels

The production of willow in short rotation is expected to result in low nitrate leaching losses as is the case with other permanent crops. However, there is a risk of leaching of nitrate during establishment when the plant cover is limited. Nitrate leaching was followed for three years from the establishment in 1993 of willow (Salix viminalis) at two sites, a coarse sand at Jyndevad and a loamy sand at Foulum. Two levels of nitrogen, 0 or 75 kg N/ha in NPK, were applied annually, though only 38 N/ha was applied in the first year.

Leaching was calculated from usually weekly measurements of the nitrate concentration in soil solution and relating with the amount of percolation based on measured precipitation and changes in the soil water content over the sampling periods. Mean leaching for the three periods 1993–94, 1994–95 and 1995–96 amounted to respectively 142, 61 and 0 kg N/ha at Foulum and to 130, 9 and 4 kg N/ha at Jyndevad. The high leaching in the first year was caused by an unusually high content of mineral N in the soil at the start of the experiment. The absence of any leaching 1995–96 at Foulum was due to very low precipitation and a consequent lack of percolation. For the first period (1993–94) the fertilized treatment increased leaching by 32 kg N/ha compared to no fertilizer as a mean of the two sites, while the difference for the following two periods was reduced to 1–2 kg N/ha. It is concluded that application of nitrogen should be avoided in the year of planting of willows, while in the following years75 kg N/ha can be given without risk of increased leaching.     

太阳辐照条件下土壤内温湿度场的动态模拟

根据质量守恒和能量守恒定律，同时对土壤非饱和区热湿迁移机理进行分析，建立了土壤非饱和区热湿迁移的理论模型。通过数值分析，模拟了太阳辐照条件下土壤内温度和含水率分布曲线。     

不同应力路径对加筋土应力—应变关系的影响

对加筋土在常规三轴上进行了三种不同应力路径（σ３＝ｃ、ｐ＝ｃ、η＝ｃ）的试验研究。结果表明：不同应力路径对加筋土的应力应变关系及抗剪强度指标—粘聚力ｃ值有较大影响，但是对其抗剪强度指标—内摩擦角φ值影响不大。     

乙炔在磁稳定床中的选择性加氢研究

 制备了一种磁性Pd/Al₂O₃催化剂，采用磁稳定床考察了活性组分负载量、反应条件及CO浓度对乙炔加氢反应性能的影响。结果表明，当反应温度80℃、反应压力1.5MPa、空速9000h－1、磁场强度（H）25kA/m时，乙炔转化率为100％，乙烯选择性可达81％，具有优良的乙炔加氢活性和乙烯选择性，优于相同反应条件下的进口催化剂；250h稳定性实验结果表明，磁性Pd/Al2O3催化剂具有良好的初活性和乙烯选择性，催化剂性能稳定。     

盐渍土地区金属管道敷设质量控制

总结了在盐渍土地区多年来的施工经验，阐述了盐渍土地区地质构造基本形态、盐渍土对金属管道及其外防腐层的作用和盐渍土地区金属管道敷设的质量控制要点，论证了管道敷设方案。敷设方案适用于盐渍土地区输油输气管道施工。     

微晶添加剂的增韧止裂效应及其机理分析

通过水泥土的抗折试验,证明了微晶作为添加剂可以增强水泥土的粘结强度。在室内试验的基础上,建立了水泥土的断裂力学模型,分析发现添加微晶后水泥土的断裂韧度普遍增大。借助SEM照片观察到水泥土的微观形貌,经过适当假设,建立了水泥土的分形弯折裂纹模型,用分形几何的理论分析了微晶水泥土增韧止裂的微观机理。     

水泥土搅拌桩的加固机理及其应用

水泥土桩加固软土地基，一般形成半刚性桩复合地基。从水泥土桩复合地基的构成，对水泥土桩桩身、垫层及桩间土的受力特性及相互作用机理进行了分析和探讨，同时对水泥土搅拌桩复合地基的设计理论进行了阐述，对施工方案及施工注意事项提出相关建议。     

控制复合土钉支护结构变形的对策

在复合土钉支护结构设计与施工中总结性地提出了控制复合土钉支护结构变形的对策，为工程设计和现场施工提供了有用的参考和指导。     

土工合成材料加筋土力学行为研究应用新进展

对目前加筋土体的室内模型试验研究、国内外土工合成材料加筋结构的理论计算分析方法及工程应用等3个方面所取得的研究进展进行了综述，比较了各种理论分析方法的适用条件和局限性，并提出了研究加筋土体的分析方法和模型试验的一些设想。     

宜春市审计局综合楼钻孔扩底灌注桩加后压浆设计分析及应用效果

江西省宜春市审计局综合楼所处场地地层条件复杂，确定合适的持力层是关键。经对地层情况、本地区已有经验以及桩基施工新技术等进行分析评估，大胆地把桩端持力层放在结构松散、性质差异较大、承载力标准值偏低的碎石土层上，采用钻孔扩底灌注桩，以提高钻孔灌注桩的承载力，并运用后压浆技术对桩底及下伏地层进行加强处理。实践证明，该方案技术可行，经济合理。