万家寨能源基地不同立地类型对新疆杨生长的影响

文章介绍了万家寨水利枢纽能源基地在不同的立地类型、不同的土壤质地条件下新疆杨生长情况。分析研究了在荒漠化区、干旱、半干旱黄主立改区影响新疆杨生长的主要立地因子，并提出一些合理配置造林树种的建议。     

LLDPE/PS塑料合金及其与木纤维形成复合材料的研究

研究线性低密度聚乙烯(LLDPE)与聚苯乙烯(PS)共混制备的塑料合金的性能并用不同制备条件的塑料合金与木纤维复合形成塑料合金/木纤维复合材料,研究该种复合材料的外观质量及物理力学性能.结果表明:不同共混比例与共混温度对制备的塑料合金熔体流动性、力学强度有较显著影响.塑料合金/木纤维复合材料的性能与塑料合金共混比例及共混温度有较强的相关性.2种塑料在共混比为50/50,共混温度为200℃时,形成的塑料合金与木纤维具有相对最好的相容性和最好的材料外观质量与力学性能.DMA试验表明:塑料合金/木纤维复合材料的耐热性明显优于相应的塑料合金.     

中国木材产业资源基础及可持续性分析

论述了发展中国木材产业的战略重要性;通过分析国内木材资源与国际木材资源供给,得出了中国木材产业资源基础薄弱的结论;以实现资源基础可持续性为目的,论述了构筑中国木材产业资源基础的途径。     

重庆荣昌国家麻竹生物产业基地发展对策研究

重庆荣昌"国家麻竹生物产业基地"是我国第1个竹类生物产业基地,也是重庆市第1个国家林业生物产业基地,大力发展麻竹生物产业,对荣昌区域经济发展和城市竞争力提高具有重要意义。文章在系统调研麻竹生物产业基地发展现状的基础上,从麻竹产业分类、基地建设的功能以及生物产业发展的目标、措施、技术支撑和动力等方面详细分析了荣昌发展麻竹生物产业的优势与劣势,提出了促进"国家麻竹生物产业基地"建设的具体建议,包括:科学制定发展思路,加快发展麻竹二、三产业,重视科技创新与成果转化,注重专业人才培养,加强政策扶持,建立多元化的投资体系等。     

云和县雪梨产业化建设进展与思考

分析了云和雪梨产业化建设的提出背景,总结了雪梨产业化建设进程中取得的经验与方法,同时在建立土地流转机制、发挥政府在雪梨产业化进程中的作用、培植龙头企业、科技创新与推广树立精品意识等方面进行了深入的思考.     

千岛湖森林康养基地发展路径探析——基于千岛湖龙川湾的调查研究

国家相关管理部门联合提出按照“环境优良、服务优质、管理完善、特色鲜明、效益明显”的要求建设一批国家森林康养基地。以浙江千岛湖龙川湾为例,分析其森林资源、地理区位、产业链、发展规模、社会合作、管理保障、三大效益等方面建设森林康养基地的优势,整合提升游憩观赏、研学文化、垂钓休闲、扶犁耕地、康养保健、疗养康复、健身拓展区域空间布局与发展举措,从康养体验、休闲体验、运动健身等方面增强千岛湖龙川湾森林康养基地功能,推进森林康养产业发展。     

Deforestation effects on soil degradation and rehabilitation in western Nigeria. IV. Hydrology and water quality

Hydrological and water-quality measurements were made on a 44·3 ha watershed under forest cover and following deforestation and conversion to an agricultural land-use. Under secondary tropical rainforest, water yield ranged from 2·2 per cent to 3·1 per cent of annual rainfall. Deforestation of 7 per cent of the watershed area increased water yield to 7·0 per cent of annual rainfall. Baseflow increased with deforestation, and increased progressively with time after deforestation. It was 5·1 per cent of annual rainfall in 1979, 15·1 per cent in 1980, 16·4 per cent in 1981 and 17·9 per cent in 1982. In comparison, surface flow was 4·5 per cent in 1979 and 6·2 per cent in 1980, but decreased to 2·3 per cent in 1981 and 2·4 per cent in 1982. Total water yield following deforestation and conversion to agricultural land-use ranged from 9·6 per cent to 21·3 per cent of the annual rainfall received. The dry season flow decreased with time as the dry season progressed, but increased over the years following deforestation. Surface runoff during the rainy season depended on ground cover and soil quality. The extent and severity of soil degradation affected the dynamics of surface flow. Because of actively growing crops, plant nutrient concentrations in surface runoff were low. Forested lysimeters had higher seepage losses than cropped lysimeters, and the water-use efficiency was 1·9–3·6 kg ha⁻¹ mm⁻¹ for cowpeas compared with 6·1–11·0 kg ha⁻¹ mm⁻¹ for maize. The delivery ratio was high immediately after deforestation and decreased to a steady value of about 3·2 per cent within 7 years. The data show five distinct phases of soil degradation in relation to generation of surface runoff. © 1997 John Wiley & Sons, Ltd.     

地下灌排兼用系统中田间土基透水管的机理分析及其现场成型机研制

通过对现有地下灌溉系统的分析，论述了田间地下土基透水管灌溉、排水兼用的可行性及机理分析。在对国内外暗管施工机进行分类归纳的基础上，研制出土基透水管现场成型机，可现场一次完成土基管的成型、固壁、防渗、镶嵌渗水条等工序，初步对样机进行了田间试验，验证其结构合理性、经济性、并对土壤的破坏成型机理进行了分析     

Base Cation Fluxes in Mountain Landscapes of Lake Baikal Southern Shore

Abstract

Assessing base cation [calcium (Ca²⁺), magnesium (Mg²⁺), potassium (K⁺)] fluxes is necessary for determining ecosystem stability. This study was conducted in the Osinovka River catchment located on the Khamar‐Daban Ridge, South Baikal, which is characterized by high precipitation (more than 1700 mm per annum). The contributions of different ecosystem components such as atmospheric deposition, soil exchange pool, minerals, vegetation, surface water, and groundwater into the total base cations flux were evaluated, combining the strontium isotope approach and budget study. Results show the leading role of atmosphere in ecosystem supply with base cations. The atmosphere contributes 48% of total base cations flux, and its contributions to plant‐available nutrition pools of both organic and mineral horizons are equal to 50%. This makes the vitality of vegetation, to a great extent, dependent on the stability of atmospheric chemistry.     

固液反应球磨制备Al-Cu-Ni三元金属间化合物粉末

利用固液反应球磨技术制备了Al-Cu-Ni三元合金粉末.采用Ni球球磨wAl-33.2%wCu,wAl-54%wCu(Al2Cu)和wAl-70%wCu(AlCu)二元合金熔体,在893 K分别球磨wAl-33.2%wCu熔体12 h和24 h后均生成了Al7Cu4Ni粉末;在893 K球磨wAl-54%wCu12h后生成Al7Cu4Ni粉末,在993 K和1 123 K球磨wAl-54%wCu(Al2Cu)24 h后均生成Al0.28Cu0.69Ni0-粉末;在1 123 K球磨wAl-70%wCu(Al2Cu)24 h后生成Al0.28Cu0.69Ni0-粉末.同时,对Al-Cu-Ni三元合金相形成规律进行了研究,对固液反应球磨机理进行了探讨.