Evaluation of aerosol lead measurement techniques using laboratory generated super-micrometer particles

High levels of lead in some occupational environments still exist. These include lead paint abatement sites, smelting operations, small arms firing ranges, and other construction scenarios. New emerging technologies provide the capability to provide an on-site alternative to conventional laboratory methods for airborne lead. In this paper we describe the evaluation of two such technologies using laboratory prepared lead-laden super-micron aerosol particles. Size measurements by TSI Aerodynamic Particle Sizer™ indicated the fluctuation of the peak particle sizes varying less than 1% among different runs for a given solution concentration. The content of lead embedded in the particles varied from 14 to 18% between runs of three different lead solution concentrations. A commercially available instrument for airborne lead measurement, AeroLead™, showed promise of becoming fully validated with the addition of design enhancements, although not fully validated by the end of the research program. Some of these areas being reworked by the manufacturer include working electrode issues, such as a more uniform surface area. Once these have been addressed, the manufacturer plans to complete the field and laboratory validation procedures. In a subsequent study, the ABF-LIPS results shown in this paper indicated that the technology could be used to quantify lead in aerosol form with a signal-to-noise ratio of three or larger of approximately 100 μg m⁻³ or higher quantity in a few minutes of measurement interval. The estimated detection limit for Pb using the ABF-LIPS prototype was approximately 60 μg m⁻³. In comparison the Resource Conservation and Recovery Act (RCRA) limit for Pb emission is 250 μg m⁻³.     

浅谈MPLS技术

近年来,随着企业对信息需求的不断提高,为增强自身的竞争力,企业逐步完善和发展自己的Intranet.本文介绍多协议标记交换技术.     

体育院校排球术科合作学习方式的实验教学研究

根据体育教育专业培养目标的特殊要求,经排球普修课术科教学中运用合作学习方式的实验研究结果表明:新的学习方式在转变学生学习态度、构建良好学习氛围,增进人际交往、提升合作意识与能力,培养教学能力、全面提高教学质量等方面成效显著。     

理科开设程序设计课程的教学思考与实践

理科开设计算机程序设计课程教学中应以解决问题为出发点，帮助学生熟悉程序设计的过程，提高应用软件的使用能力，提高学生的思维能力，同时，促进学生自主学习，加强实践环节的训练，重在落实检查．     

碳铵添加剂的生产和使用管理

简要介绍了碳铵添加刑的生产工艺、生产成本与价格、质量与消泡剂的关系以及使用问题，阐述了在碳铵添加刑的使用过程中出现的起泡带液问题、分层问题以及添加剂加入的工艺流程和操作管理等，提出了相应的解决措施。     

染色体核型研究的方法及应用

本文综述了染色体核型研究的5种基本方法及应用领域，讨论了每种方法的优点及其局限，并对核型研究的方法及应用进行了展望．     

Fabrication of a curved linear grating by using a laser direct writer system

We present the lithography technique to fabricate a curved linear grating by using a Cartesian coordinates laser direct writer (LDW) system. The grating with the period of 15 μm is made on the convex lens surface. This is a new application of the LDW system. After the chromium coating and the photoresist removing procedures, a convex reflecting grating is obtained.     

Application of mesoscale modeling optimization to development of advanced materials

The rapid development of computer modeling in recent years offers opportunities for materials preparation in a more economic and efficient way. In the present paper, a practicable route for research and development of advanced materials by applying the visual and quantitative modeling technique on the mesoscale is introduced. A 3D simulation model is developed to describe the microstructure evolution during the whole process of deformation, recrystallization and grain growth in a material containing particles. In the light of simulation optimization, the long-term stabilized fine grain structures ideal for high-temperature applications are designed and produced. In addition, the feasibility, reliability and prospects of material development based on mesoscale modeling are discussed.     

测量技术在机械制造生产线中的应用

论述了恰当的测量技术在机械制造生产线中的重要作用，分析比较了各种测量方法的优劣，提出应将能有效监督生产运行状况的质量报告单制度应用于生产实践中。     

On the multistability of spatial solitons in waveguide and optical lattice

Properties of spatial solitons in channel waveguide and optical lattice are studied with the help of projection operator approach. The nonlinearity is assumed to be of cubic-quintic type. The stability consideration of the fixed point solutions of the ODE’s governing the evolution of soliton parameters indicates to the existence of more than one branch of soliton, giving rise to multistability. Explicit numerical analysis gives more information than the standard Vakhitov–Kolokov criterion. A systematic numerical simulation of the soliton profile gives detailed information about the nature of trapping and structure of the different branches of the pulse. It is observed that even under different launching conditions the solitons do not radiate but get trapped.