SBIR Phase I: Development of Particulate Mass and Count Monitoring Instruments Using Micro-Electro-Mechanical Resonant Balances

小型企业创新研究第一阶段项目旨在开发基于微机电谐振纳米天平的低成本轻量化小型化仪器，用于实时监测空气中微/纳米颗粒的浓度和尺寸分布。直径从纳米到微米的气溶胶颗粒在空气质量、人类健康、大气能见度、地球辐射平衡（气候变化）和平流层臭氧消耗方面发挥着重要作用。工业洁净室中的气溶胶污染物会限制集成电路元件的尺寸和质量。在过去的几十年里，在轻质和低成本的气溶胶颗粒监测技术方面没有取得足够的进展，现有的技术不能满足所有现有的需求（例如在半导体工业中）。本文提出的创新方法将微/纳米级机电谐振平衡集成在小型化的微孔级联冲击器中。级联冲击器根据颗粒的大小分离气流中的颗粒，并将其沉积在指定的微/纳米级机电谐振质量天平上，进行实时质量测量。所提出的仪器可以对周围的空气进行采样，将空气中的颗粒分离成几个尺寸范围，并测量每个尺寸范围内颗粒的单个和/或累积质量。该项目的更广泛的影响/商业潜力是开发一种能力更强、成本效益更高的空气微粒监测仪。目前可用的颗粒监测系统可分为两大类：1。2.基于激光的计数器；惯性撞击。除了相对昂贵和笨重以及需要频繁校准之外，成本较低的激光计数器只能检测直径小至0.3 μ m的颗粒。另一方面，惯性撞击器可以收集直径小到几纳米的颗粒，但这种系统通常不提供自动化或实时处理能力。在这种系统中收集的颗粒物质在采样足够大体积的空气后手动称重。该技术的成功开发允许使用低成本、轻重量的仪器实时监测几纳米尺度的空气悬浮颗粒。拟议仪器的目标市场可分为两个主要部分：a)洁净室/受控环境监测。这包括半导体/微制造和制药洁净室，手术室等；b)在易于产生和扩散过量微/纳米颗粒的工业环境中用于工作场所安全的个人微粒质量暴露监测仪。这包括纳米材料加工厂、矿山（如煤矿）、金属加工厂等。

This Small Business Innovation Research Phase I project aims to develop low-cost light-weight miniaturized instruments, based on micro-electro-mechanical resonant nanobalances, for real-time monitoring of concentration, and size distribution of airborne micro/nano-particles. Aerosol particles in the diameter range from nanometers to microns play important roles in air quality, human health, visibility in the atmosphere, the radiation balance of the earth (climate change), and stratospheric ozone depletion. Aerosol contaminants in industrial cleanrooms can limit the size and quality of integrated circuit elements. There has not been enough progress in light weight and low-cost aerosol particle monitoring technologies over the past decades and the existing technologies cannot address all the existing needs (e.g. in semiconductor industry). The innovative approach proposed here integrates micro/nanoscale electromechanical resonant balances within miniaturized micro-orifice cascade impactors. Cascade impactors separate particles in the air flow based on their size and deposit them on designated micro/nanoscale electromechanical resonant mass balances performing real time mass measurement. The proposed instrument can sample the surrounding air, separate airborne particles into several size ranges, and measure the individual and/or cumulative mass of particles in each size range.The broader impact/commercial potential of this project is development of a more capable and cost effective category of airborne particulate monitors. Currently available particulate monitoring systems can be divided into two major categories: 1. Laser-based counters, and 2. Inertial impactors. Other than being relatively costly and bulky and their need for frequent calibration, lower cost laser-based counters can only detect particles with diameters as small as 0.3µm. Inertial impactors on the other hand can collect particles with diameters as small as a few nanometers, but such systems generally offer no automated or real time processing capability. Collected particulate matter in such systems is manually weighed after sampling a large enough volume of air. Successful development of the proposed technology allows real time monitoring of nanoscale airborne particles down to a few nanometers size range using low cost, light weight instruments. The target market for the proposed instruments can be divided into two major sections: a) Cleanroom/controlled environment monitoring. This includes semiconductor/micro-manufacturing and pharmaceutical cleanrooms, operating rooms, etc.; b) Personal particulate mass exposure monitors for work place safety in industrial environments prone to excessive micro/nanoparticulate generation and dispersion. This includes Nanomaterials processing plants, mines (e.g. coal mines), metal processing plants, etc.