自然冷资源的开发利用

本文介绍了我国北方丰富的自然冷资源。提出有控制地储存冬季的冷资源用于农产品的贮藏保鲜。介绍了利用自然冷资源制冰进行贮藏的原理、发展现状和特点,是一种节省能源、投资较少、质量较高的贮藏保鲜的新方法,在我国北方地区具有广阔的应用前景。     

螺旋板载荷试验探讨

螺旋板载荷试验因能旋入地面以下一定深度进行试验而广泛应用于深层地基土及地下水位以下地基土的承载力测试,根据螺旋板载荷试验的原理,经与平板裁荷试验对比,螺旋板载荷试验同样适用于浅层地基土,螺旋板面积的大小对试验成果影响不大,螺旋板载荷试验确定的承载力不再进行深度修正。     

A new shock tube configuration for studying dust-lifting during the initiation of a coal dust explosion

The traditional defence against propagating coal dust explosions is the application of dry stone dust. This proven and effective safety measure is strictly regulated based on extensive international experience. While new products, such as foamed stone dust, offer significant practical benefits, no benchmark tests currently exist to certify their dust lifting performance in comparison to dry stone dust. This paper reviews the coal dust explosion mechanism, and argues that benchmark testing should focus on dust lifting during the initial development of the explosion, prior to arrival of the flame. In a practical context, this requires the generation of shock waves with Mach numbers ranging from 1.05 to 1.4, and test times of the order of 10's to 100's of milliseconds. These proposed test times are significantly longer than previous laboratory studies, however, for certification purposes, it is argued that the dust lifting behaviour should be examined over the full timescales of an actual explosion scenario. These conditions can be accurately targeted using a shock tube at length scales of approximately 50 m. It is further proposed that useful test time can be maximised if an appropriately sized orifice plate is fitted to the tube exit, an arrangement which also offers practical advantages for testing. The paper demonstrates this operating capability with proof-of-concept experiments using The University of Queensland's X3 impulse facility.     

Exposure to insecticides in the use of cold fog generators in greenhouses

The exposure of greenhouse workers to deltamethrin and dichlorvos was studied when low‐volume misters (LVM) were used for the application of these insecticides. Exposure to deltamethrin was mainly by skin contamination and the level of exposure was low. Exposure to dichlorvos was clearly higher than to deltamethrin both through skin and inhalation. These two insecticides are different from chemical structure and character dichlorvos being a highly volatile chemical. The re‐entry period for deltamethrin was calculated to be about ten hours and for dichlorvos two or three days.     

EGSB-CASS-生物滤池工艺处理天然橡胶加工废水

根据某天然橡胶加工企业生产废水的水质特点,采用EGSB-CASS-生物滤池工艺处理天然橡胶加工废水。工程运行结果表明,该工艺对CODCr、氨氮、SS平均去除率分别达到97％,94％,90％,出水水质符合GB8978-1996《污水综合排放标准》一级标准。     

锅炉空预器堵灰的原因分析及处理措施

介绍了某电厂空预器的设计特点,该空预器运行过程中出现了一、二次风压与炉膛压力周期性波动、进出口差压偏大的问题.对该空预器实际运行情况的分析研究表明：燃用煤种含硫量超标、吹灰蒸汽带水、冬天暖风器投用不及时以及蓄热元件布置紧密是造成空预器堵灰的关键问题.通过控制入炉煤含硫量、加强吹灰、提高综合冷端温度和蓄热元件改造等措施,保证了空预器安全经济运行.     

切花保鲜原理与保鲜技术

本文综述了切花保鲜的主要原理及保鲜技术，内容包括：水分与切花衰老的关系及其保鲜技术，激素在切花衰老和保鲜作用中的最新研究进展，冷藏技术在切花贮藏保鲜中的应用，切花保鲜剂的种类及其组分和作用．     

燃煤电厂SCR烟气脱硝系统优化流场分析

以合山电厂600MW燃煤锅炉SCR脱硝反应系统的优化流场分析为例,研究数值模拟和冷态试验在电厂SCR系统流场分析中的应用。结果表明,数值模拟和冷态试验结果较为吻合,验证了数模优化方案的可行性。其中,速度场、浓度场和压降都满足设计要求,烟气经整流格栅优化后可以垂直进入催化剂层,模型中无明显积灰。     

Experimental investigations on a forced convection solar air heater using packed bed absorber plates with phase change materials

In this work, the performance of a forced convection solar air heater was evaluated using using three packed bed absorber plate configurations and compared with flat absorber plate. The phase change material (paraffin wax) was packed in the pin-fin, trianglular and circular absorber plate configurations. The performance parameters such as, outlet air temperature, thermo-hydraulic efficiency, exergy efficiency and pressure drop were predicted and compared. The results showed that the packed bed absorber plate configurations using paraffin wax have higher outler air temperature in the range of 2–5°C with 3–40% higher thermo-hydraulic efficiency and 2–20% higher exergy efficiency when compared to flat absorber plate. However, the packed bed absorver plates have higher pressure drop when compared to flat absorber plate.     

电热板消解ICP-AES法测定农田土壤中的重金属

选用盐酸-硝酸-氢氟酸-高氯酸消解体系,用电热板对土壤样品进行消解处理,采用电感耦合等离子体发射光谱法(ICP-AES)对土壤样品中铜、铅、锌、铬、锰、镍进行定量分析。实验表明,样品中所测重金属含量均满足国家二级标准,结果准确可靠,重复性好。且该方法操作简单,进样量少,定量迅速,准确度高,可同时检测多种元素,能够满足环境样品的分析。