Measuring particle size-dependent physicochemical structure in airborne single walled carbon nanotube agglomerates

As-produced single-walled carbon nanotube (SWCNT) material is a complex matrix of carbon nanotubes, bundles of nanotubes (nanoropes), non-tubular carbon and metal catalyst nanoparticles. The pulmonary toxicity of material released during manufacture and handling will depend on the partitioning and arrangement of these components within airborne particles. To probe the physicochemical structure of airborne SWCNT aggregates, a new technique was developed and applied to aerosolized as-produced material. Differential Mobility Analysis-classified aggregates were analyzed using an Aerosol Particle Mass Monitor, and a structural parameter Γ (proportional to the square of particle mobility diameter, divided by APM voltage) derived. Using information on the constituent components of the SWCNT, modal values of Γ were estimated for specific particle compositions and structures, and compared against measured values. Measured modal values of Γ for 150 nm mobility diameter aggregates suggested they were primarily composed of non-tubular carbon from one batch of material, and thin nanoropes from a second batch of material – these findings were confirmed using Transmission Electron Microscopy. Measured modal values of Γ for 31 nm mobility diameter aggregates indicated that they were comprised predominantly of thin carbon nanoropes with associated nanometer-diameter metal catalyst particles; there was no indication that either catalyst particles or non-tubular carbon particles were being preferentially released into the air. These results indicate that the physicochemistry of aerosol particles released while handling as-produced SWCNT may vary significantly by particle size and production batch, and that evaluations of potential health hazards need to account for this. Disclaimer: The mention of any company or product does not constitute an endorsement by the Centers for Disease Control and Prevention. The findings and conclusions in this paper are those of the authors and do not necessarily represent the views of the National Institute for Occupational Safety and Health.     

曲轴激光淬火工艺

为实现在将曲轴水平放置绕主轴转动条件下,对单拐或多拐曲轴的主轴和曲柄轴进行激光淬火和激光熔覆,建立了激光作用于曲拐表面形成螺线时的光斑轨迹方程。根据802D数控四轴联动激光淬火通用机床的运动特性,采用圆弧插补方法,以四轴联动方式编程,设计了激光网纹淬火数控程序。在四轴联动激光加工通用机床上实现了曲轴水平放置绕主轴转动对曲柄轴面的网纹进行激光淬火和激光表面熔覆。由于主轴匀速转动,定位不需要配重铁,工作过程稳定,可以一次装夹,不再改变曲轴回转中心,即可完成单拐或多拐曲轴的主轴和曲柄轴的激光淬火和激光熔覆,使802D数控四轴联动激光加工通用机床的功能得到发挥。     

加固显示器抗干扰滤波器设计

着重介绍加固显示器抗干扰滤波器设计的方法与技巧。介绍了共模电流对显示器干扰的影响,提出了消除干扰源的措施,给出了滤波器电路与阻抗的关系以及抗干扰滤波器在工程设计中的注意事项,并结合实践中的实例进行设计与应用。     

IP网络视频监控前端接入解决方案的研究

文中分析了目前广泛使用的几种网络视频监控前端接入方案，即DVR＋光纤收发器、DVR＋光端机、视频服务器＋光纤收发器和视频服务器＋光端机，并针对各种方案指出了其不足之处，并提出了改进措施。     

新型数字监控系统在发射机中的应用

数字电路在发射机电路设计中已受到越来越多的重视。文章结合数字电路的优势,提出了一种发射机中新型数字监控系统的设计方法,并给出了详细的设计思想及研究方案。     

电信综合告警集中显示系统方案

目前,电信现有的各类网管和监控系统的监控终端都各自独立,告警的显示都完全不同.监控中心的监控人员如果需要查看各系统的告警,必须要在不同终端上打开各自的告警界面,这样一来不能及时发现各系统的告警,二来费时费力.通过对各种网管监控系统结构的分析,论述了各类网管系统的告警信息的采集方法,并给出了综合告警的集中显示和确认的方案.     

数字电视分前端系统集成的讨论

讨论地市级分前端系统构成与维护，分析不同节目源的特点及后续处理方法，结合本地节目插入对技术指标保障作具体分析，并就EPG信息的统一规划进行细致论述。     

Constrained cost-coupled stochastic games with independent state processes

We study non-cooperative constrained stochastic games in which each player controls its own Markov chain based on its own state and actions. Interactions between players occur through their costs and constraints which depend on the state and actions of all players. We provide an example from wireless communications.     

Linear interval equations with symmetric solution sets

Criteria for symmetry and boundedness are found for the combined solution set of a system of linear algebraic equations with interval coefficients. It is shown that the problem of the best inner interval estimation of a symmetric solution set can be exactly solved by linear programming methods.     

网上黑客工具——木马探讨（续一）

5木马的危害 木马的危害主要表现在远程控制方面。木马连接建立后，控制端端口和木马端口之间将会出现一条通道。