2005.4
About Instruments Today No. 145
Gas Analysis Methods
The Monitoring of Odorous Gas [ 下載 PDF ]
Yong-Chien Ling, Hsin-Hwa Tseng, Ming-Sheng Hsu, Joseph SW Chen, Ren-Kun Chen, Jen-Yu Liu, Wen-Hsiu Hsiao, Tze-Thun Chou
Human can not survive a moment if without air. Safe and quality life requires good air. The presence of gaseous odor which we have not experienced before, such as fragrance odor could stimulate pleasant mood. On the contrary, offensive odor could make people feel unpleasant or even unsafe. The 2004 Nobel Prize in Physiology or Medicine was awarded jointly to Richard Axel and Linda B. Buck for their discoveries of 'odorant receptors and the organization of the olfactory system', which clearly reflects that olfactory system is important for life quality. This manuscript first introduces the organization and fundamental of olfactory system, followed by both domestic and foreign environmental regulations concerning odor. The instrumental and olfactory measurements of offensive odor are introduced next. Finally, application cases of monitoring odorous gases are provided to demonstrate the capability and extent of instrumental measurements.
The Environmental Monitoring Instrument of VOCs [ 下載 PDF ]
Chieh-Heng Wang, Jia-Lin Wang
Volatile organic compounds (VOCs) are pervasively present in the air and affect air quality in two aspects. The sources of VOCs are numerous and can be categorized into biogenic or anthropogenic with the latter being dominant and also posing greater hazards in terms of direct toxicity. Because the abundance of individual VOC is often low with several pptv to several tens of ppbv being the common levels, measurement of each individual VOC species with optimal precision and accuracy demands sample treatment and separation prior to detection. Direct measurement with absorption spectrometry although is fast and can obtain average abundance over a long distance, the accuracy, precision, sensitivity and compound coverage are often inadequate. Recently, the environmental monitoring of VOCs has been more relying on gas chromatographic (GC) based techniques owing to its high sensitivity, species resolution and time resolution in the range of minutes to an hour. Both flask sampling (off-line technique) and continuous automated GC measurement (on-line technique) are the two basic operation modes that account for the majority of the VOC measurement applications. In particular the on-line GC for continuous monitoring ambient VOCs is emerging as the more effective solution than the off-line usage. In this review article the basic principles of VOC analysis is reviewed; and also the basic designs or configurations of on-line systems developed in our laboratory and also found in commercial instruments are illustrated and compared.
The Real-time Gas Detect Technologies for National Security [ 下載 PDF ]
Hsin-Hwa Tseng, Yong-Chien Ling, Deng-Nan Horng, Chia-hung Lu
The most important key element in the bio-chemical agent detection process is to identify the species of the agent quickly and accurately. The sensitivities and accuracies of the sensing device are also playing a vital role. With the advance warfare agent manufacturing technology, the new generation and mixed agents have been created. This will make the present detective devices inadequate; therefore the more sophisticated and precise detective devices are needed. This paper will first review some of the present in-time detection techniques and then focus on the principle and capacities of the new generation detector — electronic nose. We also discuss the potential of electronic nose to become the bio-chemical in-time detection method in the near future.
Introduction of the Taiwan Air Quality Monitoring Stations [ 下載 PDF ]
Yu-Sung Yeh
Taiwan Air Quality Monitoring Network (TAQMN) of the Environmental Protection Agency (EPA) has established 76 air quality auto-monitoring stations and 2 movable vans. To evaluate the monitoring data is reliable and accurate, EPA has an authorized regular performance organization and an independent private sector to enforce checking for air quality monitoring annually. The items of air quality monitoring has SO2, NOx, CO, O3, HC, PM10, and meteorological data. About the data of the acid rain, UV-radiation and vaporized organic chemicals (VOCs) is also building.
Sampling and Analysis of AMC in Fab Air [ 下載 PDF ]
Sylvia Huang
The importance of monitoring of airborne molecular contaminants (AMC) has increased with the shrinkage of line width in semiconductor manufacturing. The definition of AMC, their impact on semiconductor production, possible sources, timing for sampling and the off-line technique of sampling (impinger, adsorbent tube, canister, witness wafer and surface wiping) and methods of analysis are introduced. Two application examples are also included, one is MA analysis and the other is sulfur containing compound analysis.
Study of Nanotribological Properties of Hard Coating Materials by Friction Force Microscopy [ 下載 PDF ]
Hsin-Yu Lin, Yu-Ju Chen, Tsu-Hsien Ku, Heh-Nan Lin, Yu-Ching Fang, Shan Torng
The nanotribological properties of hard coating materials have received great interest in recent years due to the use of film thickness below 100 nm. A quantitative friction measurement technique with nanoscale resolution is highly desirable for the evaluation of film homogeneity and tribological properties. For this purpose, atomic force microscopy with friction measurement, which is also called friction force microscopy, is well-suited for nanotribological research. In this paper, a quantitative friction measurement technique is introduced. The friction coefficients between a silicon tip and titanium nitride and diamond-like-carbon films have been obtained. In addition, a repeated scanning on a specific surface region up to several tens or hundreds of times can cause surface wear. By comparing the surface morphologies before and after the repeated scanning, the nanotribological properties of the two films have been evaluated.
Application of Two Photon Microscopy in Biomedical Optics [ 下載 PDF ]
Yen Sun, Wesley Chen, Chang-Chun Lee, Yuan Liu, Chen-Yuan Dong
The recent rapid development of laser application has led to breakthrough like growth in two-photon microscopy. Two-photon microscopy with femtosecond pulsed laser has demonstrated the possibility of optical biopsy. The advantages of this imaging technique include less photodamage and greater imaging depth. It allows in vivo observation and avoids many problems associated with histology. The characteristics of two-photon microscopy have clear advantages in the field of biomedical imaging. This article gives an introduction to the theory and experimental setup of twophoton microscopy, and describes the application of the technology to the investigation of transdermal drug delivery, thermal damage of collagen, and liver cirrhosis.
Superconducting Quantum Interference Devices and Biomagnetism [ 下載 PDF ]
Hong-Chang Yang
Superconducting quantum interference device (SQUID) is the most sensitive detector of the magnetic flux. Since the discovery of the high-Tc superconductor substantial effort has been expended to develop SQUID devices that can be operated at temperature above the boiling temperature of the liquid nitrogen. The grain-boundary and the step-edge Josephson junctions are the promising devices for high-Tc SQUIDs. Typical levels of white flux noise are a few µΦ0/Hz1/2 for low-Tc SQUID and ∼ 10 – 40 µΦ0/Hz1/2 for high-Tc SQUIDs. This corresponds to a magnetic field sensitivity of 1 – 5 fT/Hz1/2 and ∼ 10 – 40 fT/Hz1/2 for low-Tc and high-Tc SQUID magnetometers respectively. The low frequency 1/f noise from thermally activated motion is a much bigger issue for high-Tc SQUID than low-Tc SQUID because the low pinning energy in high-Tc superconductors at 77 K. The noise level depends strongly on the YBa2Cu3Oy (YBCO) film quality and much effort has been devoted to improve the quality of the YBCO film. There is a considerable effort to apply high-Tc SQUID in biomagnetism, for example, magnetocardiology, immunoassay, nuclear magnetic resonance imaging in low magnetic field, detection of the DNA and boimagnetic field from the heart cells, and other novel research.
Introduction to Plastic Coatings and Its Fabrication Process [ 下載 PDF ]
Han-Chang Pan, Hung-Pin Chen
There is an interest to replace glass with polymeric materials in many applications, such as automobile, transportation, architectures and flexible optoelectronics due to its lightweight and enhanced impact resistance. The main limitation of plastic-based components is the softness of their surface, which corresponds to low abrasion resistance and weak adhesion between the films and the plastic substrate. Protecting hard coating and surface modification should be carried out prior to deposit functional coating on the plastic surface to increase its durability. In this paper, a barrier layer coating, surface modification, novel low-temperature leaser annealing technique and characterization of mechanical properties are discussed in order to obtain a high-quality plastic coating components.
