太阳能集热器的热流气体对砾石的蓄放热特性研究

太阳能的蓄放热特性的研究对清洁能源太阳能的开发和利用具有重要意义。该文利用冬季太阳能集热器的热流气体,对砾石的蓄放热特性进行了研究。以居民居住的标准房间（4 m×2.7 m）为依据进行了模拟;利用太阳能集热器的热能与直径为50～100 mm的砾石铺设成150 mm厚度的地下蓄热系统进行蓄热和放热试验,研究昼夜之间室内砾石的蓄热和放热特性;通过测试太阳能集热器的内部温度、砾石层内部及室内地表面的温度,研究了太阳能集热器的蓄热效率和转换效率,同时分析了蓄热层及室内地表面的热传递特性;为进一步开拓针对冬季寒冷地区太阳能蓄热型居民建筑物内部热环境方面的基础研究提供了科学的依据。     

Three‐dimensional scanning for measurement of bulk density in gravelly soils

The measurement of bulk density in gravelly soils (>15% soil particles >2 mm) is more time‐consuming than for other soils. The excavation method, usually employed for measurement of bulk density in gravelly soils, includes excavating a void and calculating volume of the void from the weight and density of the material (e.g. sand and plaster cast) used to fill the void. A 3‐dimensional (3D) scanning system was developed to measure the volume of the void created when using the excavation method. The 3D scanning system combined a time‐of‐flight camera (Kinect ™), the KinectFusion algorithm, MeshLab and a portable computer to produce a 3D model of the void or plaster cast. Experiments were completed at three field sites where soil gravel (>2 mm) content ranged from 35 to 71% to assess the performance of the system. The void volume measured using the 3D scanning system was highly correlated with measurements using the plaster cast method (r  = 0.99). The cumulative time taken to measure soil bulk density using 3D scanning was significantly (P  <  0.001) less than for the sand replacement at 0–10, 10–20, 20–30 and 30–40 cm depth. The faster measurement of subsurface bulk density is a significant advantage of the 3D scanning system; the time taken to measure bulk density to 40 cm in 10 cm increments using the 3D scanning system was about one‐third of the sand method.     

浅谈水井钻进方法与成井工艺

作者依据多年水文地质钻探工作的经验,阐明了在不同地质条件的情况下,所选用不同的钻进方法和成井工艺,对确保成井质量具有决定性作用。     

路面基层水稳砂砾裂缝分析及防治办法

结合黑龙江省水泥稳定砂砾施工裂缝的防治、分析及处理办法,从选定料源,进场材料控制,施工含水量、摊铺时间进行控制,就能有效减少裂缝病害的出现。     

路用砾石混凝土级配探讨

主要根据砾石混凝土的性能指标,对混凝土进行室内试验,通过混凝土配合比设计,进行多次调配,得出合理配合比,并对试验结果进行分析、探讨。得出:水泥用量越大其抗析强度越高、集料粒径对混凝土的影响也很明显,砾石混凝土的抗析强度完全能满足路用要求。     

Soil mulching can mitigate soil water deifciency impacts on rainfed maize production in semiarid environments

Temporaly irregular rainfal distribution and inefifcient rainwater management create severe constraints on crop production in rainfed semiarid areas. Gravel and plastic iflm mulching are effective meth...     

Research and developments in selecting subsurface drainage materials

Subsurface drainage requires appropriate materials to ensure a proper functioning of the drainage system. The materials normally applied for subsurface drainage are drain pipes and envelopes. Besides a review of the materials used for drain pipes, their hydraulic characteristics — discharge capacity and entrance resistance — have been treated. Much attention is paid to subsurface drainage envelope materials because of practical problems and a serious gap in knowledge, in spite of considerable research efforts. After treating the aim of drainage envelopes, a review of the used materials is given. Practical experience with gravel envelopes, still often used in irrigated areas, shows serious shortcomings. Since organic envelopes are vulnerable to deterioration, the only possible alternative are synthetic envelopes. Their property to retain soil particles is characterized by the so-called filter criteria. Laboratory research and field experiments to evaluate the blocking and clogging aspects of synthetic envelopes are discussed and selection criteria given.     

卡拉贝利工程区植物的防风蚀效果

[目的]研究新疆卡拉贝利工程区植物防风固沙效果,为该地区的风沙治理措施提供理论依据,[方法]对该地区的植被进行了防风蚀效果的调查研究,主要收集了植被的盖度、冠幅、高度等植被特征和植被积沙特征的数据,采用SPSS等统计软件进行数据的统计分析,并利用曲线估计的方法建立植物形态与积沙量的回归模型,量化分析植物形态特征与植物积沙的关系。[结果]该地区植被以盐爪爪为主,并伴有少量骆驼刺、假木贼等植物;不同砾石覆盖度对植被的密度和盖度影响较大,对植物的高度、冠幅影响较小,且砾石覆盖度越高植被密度和盖度越低;植物积沙量、植物积沙丘的厚度与宽度均随着植物高度和冠幅的增加而呈指数增加;植物形态对积沙量增加的影响程度表现为:植物高度纵向冠幅横向冠幅。[结论]该地区植被具有一定的防风蚀能力,其防风蚀效果的大小与植被的形态以及地表砾石含量存在很大的关系。     

泥石流堆积层理结构的分析研究

应用层理结构的分类指标——流核比 ,对泥石流堆积层理的正粒序、反粒序和混杂粒序等进行成因差异分析。当粘性泥石流体的流核比在 12～ 5 0之间时 ,砾石质点在蠕动流场中作向上垂直运动 ,形成筛积的层理结构。     

路面基层材料水泥稳定沙砾抗冻性研究

水泥稳定砂砾以其强度高,板体性好以及一定的水稳定性和耐久性,广泛应用于公路路面基层,但也存在一定的抗冻性问题。以半刚性基层材料水泥稳定沙砾为研究对象,在总结国内外研究成果的基础上,通过室内试验确定不同级配的水泥稳定砂砾在不同含水量、不同温度下、经冻融循环后的耐久性。对水泥稳定砂砾的低温性能进行比较,以确定保证半刚性基层材料水泥稳定砂砾强度的最佳配合比,以期指导工程实践。