VMA1000胶料流动性分析仪在橡胶加工中的应用

针对目前橡胶行业普遍运用门尼黏度表征胶料加工流动性的现状,阐述了门尼黏度与流动性的不同以及产生流动性差异的原因。重点运用新型VMA1000胶料流动性分析仪,对实际胶料生产进行检测与质量控制,分析了影响胶料加工流动性的因素和流动性对橡胶加工的重要意义。     

Sub-micrometer particulate air pollution and cardiovascular mortality in Beijing, China

Background

While the link between particulate matter and cardiovascular mortality is well established, it is not fully investigated and understood which properties of the aerosol might be responsible for the health effects, especially in polluted mega-city areas.

Objectives

Our goal was to explore the association between daily cardiovascular mortality and different particle metrics in the sub-micrometer range in Beijing, China.

Methods

We obtained daily counts of cause-specific cardiovascular deaths in the Beijing urban area for the period March 2004 to August 2005. Concurrently, continuous measurements of particle number size distributions were performed. Particle number concentrations (NC) between 0.003 μm and 0.8 μm were converted to particle mass and surface area concentrations assuming spherical particles. Semi-parametric Poisson regression models adjusting for trend, seasonality, day of the week, and meteorology were used to estimate immediate, delayed and cumulative particle effects. Additionally, effect modification by air mass origin was investigated.

Results

We observed associations between daily cardiovascular mortality and particle NC for a 2-days delay. Moreover, nearly all particle metrics showed 2-days delayed associations with ischemic heart disease mortality. The strongest association was found for particle NC in the size range 0.03-0.1 μm (7.1% increase in daily mortality with a 95%-confidence interval of 2.9%-11.5%, per an increase of 6250 particles/cm³). Results for surface and mass concentrations with a lag of two days indicated effect modification by air mass origin, whereas effects of particle NC were not modified.

Conclusions

Results show an elevated risk of cardiovascular mortality in Beijing from short-term exposure to particulate air pollution in the sub-micrometer range. Results also indicate that locally produced smaller particles and regionally transported particles may exhibit different effects in Beijing.     

One Pot Cooking of Rice Grains for Preparation of Rice-Gel Samples Using a Small-Scale Viscosity Analyzer: Small-scale Rice-gel Preparation from Grains

Rice-gel prepared by the following three steps: rice grain cooking, shearing of the cooked rice, and cooling for gel formation, is expected as a novel food ingredient for modification of various food products such as bread and noodles. To meet the demand for high-throughput systems for research and developments on the new rice gels, herein we established a mini-cooking system for preparation of rice gel samples from grains using a small-scale viscosity analyzer (Rapid Visco Analyzer; RVA). Polished rice grains (4 g) were cooked with 22 mL of water in a canister, and the paddle equipped in the canister was rotated at 2,000 rpm for 30 min (80 °C was used as a representative) to shear the cooked rice. The sheared paste was cooled to 10 °C at 160 rpm, and the initial gelation property was evaluated by viscosity analysis within the RVA. Alternatively, the sheared paste was transferred to an acrylic mold and kept at 4 °C for 0, 1, 3, and 5 days for determination of the hardness with a compression test. Compressive forces required to penetrate 20 % thickness for three tested rice cultivars were measured, and the trend of the value shifts during preservation is similar to the corresponding trend obtained in 300-g grain scale laboratory tests, whereas the individual values were halved in the former. This small cooking method could offer a useful assay system for a rapid evaluation in the breeding programs and in the high-throughput screening of additives for the modification of properties.     

矢量网络分析仪的校准方法

该文简单介绍矢量网络分析仪的工作原理,重点阐述误差修正原理以及与误差修正相关的校准件、校准方法和如何进行校准质量的评估。     

MEMS质谱仪研究综述

近年来,小体积、低功耗、价格低廉、使用方便的MEMS质谱仪成为了质谱领域的研究重点和热点。目前国外对MEMS质谱仪及其相关技术的研究已取得了一些成果,甚至研发出了较为完整MEMS质谱仪。但是整体而言,MEMS质谱仪的性能还很低,其研究主要还处于对其元件分别进行微型化的阶段。其中,MEMS离子源以对电喷雾离子源的研究为主;MEMS质量分析器以对离子阱的研究为主;MEMS离子检测器以对法拉第筒的研究为主。本文总结了MEMS质谱仪的最新成果,同时分析了可能面临的问题。     

旋流器内空气核的形成机理和形状的实测研究

首次采用先进的高速摄象机对旋流器内空气核的出现、发展直至形成的整个过程以及形成后的形状进行了全面系统的实测研究。研究发现空气核的形成经历了孕育、发展及形成三个不同的阶段;在旋流器内不同的高度,空气核的形状有所不同,在底流口上端发生最大程度的偏摆,而在溢流管内出现类似“葫芦”形状;旋流器的进口流量和锥角对空气核的形成过程及形状尺寸有着重要的影响。空气核的形成运动过程为一随机过程,这是造成分离过程具有随机特性的主要因素之一。     

Athena 120全自动离散化学分析仪测定水中硝酸盐/亚硝酸盐的研究

本文研究了使用Athena 120全自动离散化学分析仪测定水中硝酸盐/亚硝酸盐方法,采用硝酸盐还原酶还原硝酸盐为亚硝酸盐（还原效率接近100%）后,与Griess试剂反应进行吸光度检测。结果显示：硝酸盐和亚硝酸盐测定线性范围分别为0.5～10mg/L（r〉0.999）,0.001～10mg/L（r〉0.999）,质控样测定结果满意,硝酸盐的精密度1.25%,亚硝酸盐精密度0.29%,对实际样品进行加标回收测定,回收率均在在91.4%～108%之间,样品分析通量120样/小时,硝酸盐还原采用酶法和镉柱法进行t配对,无显著性差异。     

操作站与分析仪显示不一致的故障分析与处理

介绍一起由信号干扰引起的粗氩冷凝器出口氩含量在线分析仪显示与DCS控制系统操作站上显示不一致的故障现象,并提出了相应的整改措施。     

Ion dynamics in plasma processing for the fabrication of ultrafine structures

The flux, energy and angular distribution of ions generated from inductively coupled argon plasma were measured, using a gridded retarding field ion analyzer, to investigate the dynamics of ions in the plasma. The ion flux and the ion density at the sheath edge were found to increase with power, but to decrease with pressure. The ion energy was modulated, showing two peaks in the argon plasma, because the ratio of the ion transit time to the rf period was less than or comparable to unity. The peak, mean, minimum, and maximum ion energy decreased with increasing pressure, but were nearly constant as power was varied. The ion angular distributions had a Gaussian distribution peaked at zero angle from surface normal. The full-width-at-half-maximum was increased with increasing both power and pressure. The ion temperature was readily obtained from the ion angular distributions, and the value was in the range of 0.08–0.14 eV, agreeing with typical ion temperature values measured previously in inductively coupled plasmas.     

分布式半导体激光在线气体分析仪在安全生产中的应用

本文论述了在煤气净化过程中含氧量高的危害，介绍了LGA-3100分布式半导体激光在线气体分析仪的组成及其测量原理，给出了分析仪在线测量的控制方法，系统运行可靠。