《中国21世纪议程》战略规划即将出台

最近，国家计委和国家科委联合举办了《中国21世纪议程》首期培训班，为实施《中国21世纪议程》作准备。     

京津冀晋地区80年代的干旱及其对水资源的影响

本文利用１９５１～１９８９年气象资料及１９５６～１９８４年水文资料，统计分析了京津冀晋地区降水量和水资源各分量的变化趋势，强调了８０年代干旱对水资源的影响，建立了水资源总量与降水量之间关系的统计模式。     

1．2L Harttman管式与20L球型爆炸测试装置爆炸猛度实验研究

随着现代工业的发展,粉尘爆炸的危险性几乎涉及到所有的粉体工业部门,因此对粉尘爆炸危险场所进行危险性分析成为一种必然。粉尘爆炸的猛度参数是危险性分析的重要参数,反应了粉尘爆炸的猛烈程度,同时也是设计和选用泄爆、隔爆、抑爆等不同防爆技术方法的基础。然而,对于不同的测试装置所测得猛度参数有所不同。本文分别利用1．2L Haitmann管与20L球形爆炸装置对玉米淀粉的爆炸猛度参数进行了测试,并对相应结果进行了对比分析。     

21世纪初厦门市环境保护策略探索

在21世纪初厦门基本实现现代化的关键时期，厦门市如何坚持可持续发展战略，营造滨海生态城市，该文提出了环境保护的发展方略。     

打击官煤勾结任重道远

这是诞生在20世纪50年代中期的《青年友谊圆舞曲》里的一段歌词。在当年下乡插队的日了里，我们这些来自城市的知识青年，常常在狭窄、崎岖、蜿蜒而泥泞的乡路上哼唱。不仅因为喜欢它欢快的旋律，也因为向往歌中那种大路宽阔的城市生活。那种哼唱如同一根灯草，续燃着我们回归城市生活的希望与梦想。     

Effects of temperature change and tree species composition on N2O and NO emissions in acidic forest soils of subtropical China

Tree species and temperature change arising from seasonal variation or global warming are two important factors influencing N2O and NO emissions from forest soils. However, few studies have examined the effects of temperatures(5–35℃) on the emissions of forest soil N2O and NO in typical subtropical region. A short-term laboratory experiment was carried out to investigate the influence of temperature changes(5–35℃) on soil N2O and NO emissions under aerobic conditions in two contrasting(broad-leaved and coniferous) subtropical acidic forest types in China. The results showed that the temporal pattern of N2O and NO emissions between the three lower temperatures(5℃, 15℃, and 25℃) and 35℃ was significantly different for both broad-leaved and coniferous forest soils. The effects of temperature on soil N2O and NO emission rates varied between broad-leaved and coniferous forest soils. Both N2O and NO emissions increased exponentially with an increase in temperature in the broad-leaved forest soil. However, N2O and NO emissions in the coniferous forest soil were not sensitive to temperature change between 5℃ and 25℃. N2O and NO emission rates were significantly higher in the broad-leaved forest soil as compared with the coniferous forest soil at all incubation temperatures except 5℃. These results suggest that the broad-leaved forest could contribute more N2O and NO emissions than the coniferous forest for most of the year in the subtropical region of China.     

湖底发电厂参观记

20世纪60年代初,新西兰政府为了建这座发电厂决定在玛纳波里湖上游筑坝,抬高水位30多米。消息一出,立即遭到了新西兰人的反对……     

与自行车结缘

不知什么缘故,从小就对自行车有着一种特殊的感情。那是个物质匮乏的年代,人们的衣食住行都十分简单,收入也不高,家里如果有一辆自行车,那就不得了了,算得上是一件奢侈品,骑进骑出十分神气,车还没到,就能听到一阵悦耳的铃声,引来众人羡慕的眼光。骑车者的神气劲,不亚于今天开"宝马"。那时,难得的星期天,家里有自行车的,都在忙着清洗、擦拭。     

Effect of initial material bulk density and easily-degraded organic matter content on temperature changes during composting of cucumber stalk

To inactivate the potentially pathogenic microorganisms and safely utilize vegetable waste compost, ultra-high temperatures( 70°C) should be maintained during the composting without having an inhibitory effect on maturity. This study investigated the influence of bulk density(part 1) and easily-degraded organic matter content(EDOMC, part 2) on temperature evolution during vegetable waste composting: Part 1: corn straw with different particle sizes was used to achieve different bulk densities in the composting material(BD1–BD3); Part 2: partial or total substitution of the corn straw by corn starch was carried out to obtain different EDOMC(ED1–ED4). The composting experiments were conducted in a labscale reactor(1.75 kg material) and lasted for 30 d. Temperature and CO2 emission were recorded daily, and the organic matter, lignocellulose, microbial activity, germination index(GI) and C/N of the samples were measured at different stages. The highest temperature(65.7°C) in part 1 occurred in the treatment with the bulk density of 0.35 g/cm3, which also had the longest thermophilic phase. Bulk density was found to seriously influence the utilization efficiency of O2 and heat transfer through materials, rather than heat production from organic matter degradation. In experiment part 2, the highest temperature was obtained with EDOMC of 45%(71.4°C). Therefore, adjusting the bulk density to 0.35 g/cm3 and the easily-degraded organic matter content of the initial material to 45% was the best combination for reaching temperatures above 70°C during composting, with no inhibitory effect on the maturity of the compost product.     

某20#钢腐蚀穿孔失效原因分析

目的 某船20#钢管投运不久后管段出现严重的腐蚀穿孔,通过对失效管段进行研究,以分析其失效原因。方法 通过电感耦合等离子体发射光谱仪、碳硫分析仪、金相显微镜等对材料材质进行材质符合性分析及金相组织分析。通过场发射扫描电子显微镜观察蚀坑微观形貌,并结合X射线衍射仪及显微拉曼光谱仪,对失效部位周围的腐蚀产物进行成分分析。通过电化学测试及微生物鉴别培养,进一步确定腐蚀的发生原因及机理。结果 材料符合性分析说明,此20#钢管束成分符合标准要求。通过形貌观察发现,20#钢蚀坑边缘呈阶梯状,具有明显的攀爬现象,蚀坑周围呈黑色。X射线能谱仪分析结果表明,20#钢腐蚀穿孔处内表面异常存在大量硫元素。通过拉曼分析及XRD分析发现,硫元素主要以硫酸盐及硫化物的形式存在。电化学测试结果表明,在含硫化物的溶液中,20#钢的腐蚀速率明显提升。进一步对腐蚀产物进行微生物培养,发现了硫酸盐还原菌的存在。结论 微生物腐蚀是引起20#钢管束穿孔的主要原因。