提升环境监测质量管理水平的探讨

随着当前我国的环境破坏日益严重,环境问题已经威胁着人们的身体健康和生活质量,这就需要加强对环境治理工作的开展实施,做好环境监测的工作。本文先就环境监测的工作方式和工作意义进行简要的阐述,然后就当前环境监测工作中存在的问题,以及如何提高环境监测水平展开详细探究,希望能从理论层面对环境监测深入探究,为解决环境监测中的实际问题起到一定的借鉴作用。     

国家发展和改革委员会、商务部就民营成品油企业经营有关问题发出通知

<正>近日,国家发展和改革委员会、商务部就民营成品油企业经营有关问题发出通知。通知指出,经国务院同意,现就民营成品油企业经营有关问题通知如下:(1)依法规范民营成品油企业经营。(2)     

喷射器在我国热能及动力工程中的应用

本文就我国锅炉给水除氧、供热采暖、凝汽器抽真空等热能及动力工程方面的问题 介绍了喷射器的应用现状,并就应用中存在的问题,提出了喷射的研究方向,对喷射器的发展趋势作了一定的分析.     

高分子电解质在染料敏化太阳电池中的应用

用高分子电解质代替液态电解质是解决电解质密封问题的有效途径。本文就高分子电解质,包括可用作空穴传导材料的导电高分子、高分子凝胶电解质及高分子固态电解质的研究进展及存在的问题进行了综述,并就今后的发展进行了分析。     

政策信息

国家发展和改革委员会就进一步完善电煤价格临时干预措施发出通知；2007年各省自治区直辖市节能目标完成情况;国家发展和改革委员会就抽水蓄能电站建设管理有关问题发出通知；国务院办公厅就深入开展全民节能行动发出通知。     

介入放射学研究生教学改革初探

【摘要】 目前介入放射学研究生教学存在教育质量下降、高端人才流失等问题，本文就介入放射学研究生教学的现状和存在问题及原因进行剖析，并就如何培养综合素质高、迎合学科发展的研究生人才队伍进行初步探讨。
     

城市变电站选址及其对环境影响探讨

对城市变电站建设中公众关注的电磁环境影响及人体健康问题进行探讨,就变电站的选址问题提出建议.     

工厂电压波动和闪变初探

本文阐述目前北方企业存在的电压波动和照明"闪变"的根源.就现象追踪源头,就存在的问题提出相应的解决办法.     

浅议喷油泵维修企业存在的问题及对策

本文就油泵油嘴维修企业现状提出存在的问题,通过对问题的分析,探讨出将来企业发展的对策。     

消防系统施工技术存在的问题及对策分析

随着时代的发展,人民生活水平日益提高,城镇建设不断增加,这就意味着城镇消防工作日益加重,近年来,城镇施工中消防工作越来越多,随之带来越来越多的消防施工问题。由于消防施工中存在的问题,导致越来越多的火灾发生,不仅对城镇施工建设造成一定的阻碍,而且对居民的生命安全也造成了一定的威胁,所以,如何完善城镇消防施工问题是一重要难题,因此,就消防系统施工技术存在的问题以及如何解决这些问题进行了探讨。     

Accurate experimental (p, ρ, T) data of natural gas mixtures for the assessment of reference equations of state when dealing with hydrogen-enriched natural gas

The GERG-2008 equation of state is the approved ISO standard (ISO 20765-2) for the calculation of thermophysical properties of natural gas mixtures. The composition of natural gas can vary considerably due to the diversity of origin. Further diversification was generated by adding hydrogen, biogas, or other non-conventional energy gases. In this work, high-precision experimental (p, ρ, T) data for two gravimetrically prepared synthetic natural gas mixtures are reported. One mixture resembled a conventional natural gas of 11 components (11 M) with a nominal mixture composition (amount-of-substance fraction) of 0.8845 for methane as the matrix compound with the other compounds being 0.005 for oxygen, 0.04 for nitrogen, 0.015 for carbon dioxide, 0.04 for ethane, 0.01 for propane, 0.002 each for n- and isobutane, and ultimately 0.0005 each for isopentane, n-pentane, and n-hexane. The other mixture was a 13-component hydrogen-enriched natural gas with a low calorific value featuring a nominal composition of 0.7885 for methane, 0.03 for hydrogen, 0.005 for helium, 0.12 for nitrogen, 0.04 for carbon dioxide, 0.0075 for ethane, 0.003 for propane, 0.002 each for n- and isobutane, and 0.0005 each for neopentane, isopentane, n-pentane, and n-hexane. Density measurements were performed in an isothermal operational mode at temperatures between 260 and 350 K and at pressures up to 20 MPa by using a single-sinker densimeter with magnetic suspension coupling. The data were compared with the corresponding densities calculated from both GERG-2008 and AGA8-DC92 equations of state to test their performance on real mixtures. The average absolute deviation from GERG-2008 (AGA8-DC92) is 0.027% (0.078%) for 11 M and 0.095% (0.062%) for the 13-component H₂-enriched mixture, respectively. The corresponding maximum relative deviation from GERG-2008 (AGA8-DC92) amounts to 0.095% (0.127%) for 11 M and 0.291% (0.193%) for the H₂-enriched mixture.     

Thermoelastic Equilibrium of Some Semi-Infinite Domains Subjected to the Action of a Heat Source

By using the integral representations for main thermoelastic Green's functions (MTGFs) we prove a theorem about new structural formulas for MTGFs for a whole class of boundary value problems (BVPs) of thermoelasticity for some semi-infinite Cartesian domains. According to these new structural formulas many MTGFs for a plane, a half-plane, a quadrant, a space, a quarter-space and an octant may be obtained by changing the respective well-known GFPE and their regular parts. The crucial moment of our investigation consists of elaboration of a new technique for calculating some generalized integrals containing products of two different GFPEs. Also, the types of boundary conditions for volume dilatation considered and GFPE for temperature differ on a single boundary only. As example of application of the obtained new structural formulas, the new MTGFs for a concrete BVP of thermoelaesticity for an octant are derived in elementary functions. The MTGFs obtained are validated on a known example for a BVP for half-space. Graphical computer evaluation of the derived in elementary functions new MTGFs is included.     

高速铰削双层合金材料的硬质合金铰刀

阐述叶片叶轮两种不同性能合金钢装配后的铆钉孔铰削问题,论述了加工铆钉孔用铰刀材料选择及刀具结构和几何角度设计,给出加工铆钉孔的工艺参数,说明了使用效果。     

Comparative studies on Ar and He closed-cycle MHD power plants combined with fossil fuel

Comparative studies on Ar and He closed-cycle MHD power plants combined with fossil fuel are performed. The sizes of a regenerative heat exchanger and a boiler are expected to be smaller for He than for Ar. The pressure loss of a working gas in a regenerative heat exchanger is reduced for He. The purification subsystem for He is expected to be more compact and economical than that for Ar; but a larger compressor is required for He than for Ar.     

Comparative impacts of wind and photovoltaic generation on energy storage for small islanded electricity systems

This paper addresses the annual energy storage requirements of small islanded electricity systems with wind and photovoltaic (PV) generation, using hourly demand and resource data for a range of locations in New Zealand. Normalised storage capacities with respect to annual demand for six locations with winter-peaking demand profiles were lower for wind generation than for PV generation, with an average PV:wind storage ratio of 1.768:1. For two summer-peaking demand profiles, normalised storage capacities were lower for PV generation, with storage ratios of 0.613:1 and 0.455:1. When the sensitivity of storage was modelled for winter-peaking demand profiles, average storage ratios were reduced. Hybrid wind/PV systems had lower storage capacity requirements than for wind generation alone for two locations. Peak power for storage charging was generally greater with PV generation than with wind generation, and peak charging power increased for the hybrid systems. The results are compared with those for country-scale electricity systems, and measures for minimising storage capacity are discussed. It is proposed that modelling of storage capacity requirements should be included in the design process at the earliest possible stage, and that new policy settings may be required to facilitate a transition to energy storage in fully renewable electricity systems.     

Development of methods for evaluating hydrogen compatibility and suitability

The embrittlement of metals exposed to hydrogen environments is well documented. With the deployment of hydrogen fuel cell vehicles in the consumer sector, there is a need to improve the engineering basis for the selection of materials of construction for equipment that stores and distributes high-pressure gaseous hydrogen. This brief overview summarizes publicly available guidance for evaluating materials compatibility with high-pressure gaseous hydrogen. Additionally, a new standard for measuring engineering data in gaseous hydrogen and evaluating materials suitability for service in gaseous hydrogen is introduced: the CHMC1 standard provides a general framework for qualifying materials for hydrogen service. The CHCM1 standard is unique in its broad scope and performance-based strategy for quantitatively assessing materials in their service environment and for the intended structural requirements.     

Forest biomass and Armington elasticities in Europe

The purpose of this paper is to provide estimated Armington elasticities for selected European countries and for three forest biomass commodities of main interest in many energy models: roundwood, chips & particles and wood residues. The Armington elasticity is based on the assumption that a specific forest biomass commodity is differentiated by its origin. The statistically significant estimated Armington elasticities range from 0.52 for roundwood in Hungary to approximately 4.53 for roundwood in Estonia. On average, the statistically significant Armington elasticity for chips & particles over all countries is 1.7 and for wood residues and roundwood 1.3 and 1.5, respectively. These elasticities can provide benchmark values for simulation models trying to assess trade patterns of forest biomass commodities and energy policy effects for European countries or for the EU as a whole.     

浅谈外压圆筒及其加强圈的设计

介绍了外压圆筒的设计方法、加强圈最大间距的计算、加强圈截面尺寸的确定方法、加强圈的快速计算方法及外压圆筒的程序计算。     

Chemical looping reforming of ethanol for syngas generation: A theoretical investigation

Chemical looping reforming (CLR) is a novel technology that can be used for reforming of cheaply available abundant biofuel like ethanol for the production of hydrogen/syngas for fuel cells. A systematic thermodynamic study for the CLR process using selected oxygen carriers was done to analyze the products and energy requirements of the CLR process in the temperature range of 500–1200 °C at 1 bar pressure for ethanol. The results showed favorable conditions for syngas manufacture from this process. Fe₂O₃ was found to be the best performing oxygen carrier followed by calcium and sodium sulfates, while Mn oxides were the least preferred oxygen carriers for CLR of ethanol process. The optimum process temperature was found to be 1000 °C. The actual CLR‐ethanol process shows exothermicity against the theoretical endothermic partial oxidation of ethanol. The results obtained in this theoretical study can pave the way for experimental programs for syngas generation for SOFC‐type fuel cells. Similar studies can be undertaken for other fuels for fuel processor development by CLR process. Copyright © 2012 John Wiley & Sons, Ltd.     

ND5型机车主轴瓦碾瓦前的光谱数据分类及其应用

通过对机车出现故障前的光谱数据分析,总结和归纳数据异常的特征,并对其进行分类,明确各类型的特征和扣检时机,形成数据分析的参照样本,从而指导数据分析,以减少漏报和误报的发生,是光谱分析标准的细化和重要补充。