Browsing by Author "Chang, SY"

Now showing 1 - 5 of 5

Differences in PM10 concentrations measured by beta-gauge monitor and hi-vol sampler
(2001-11-01)
Chang, CT
;
Tsai, CJ
;
Lee, CT
;
Chang, SY
;
Cheng, MT
In this paper. differences between the 24-h average PM10 concentrations of Wedding beta -gauge monitor and Andersen or Wedding hi-vol sampler were studied. When the deliquescent point is not exceeded, PM10 concentrations of the beta -gauge are close to those of the manual samplers. The ratio of beta -gauge PM10 to Andersen PM10 and Wedding PM10 is 1.08 +/-0.06 and 1.09 +/-0.12, respectively. However, when the deliquescent point is exceeded, water absorption by the inorganics of aerosols leads to higher PM10 concentrations of the beta -gauge compared to those of the manual sampler. The ratio of beta -gauge PM10 to Andersen PM10 and Wedding PM10 is 1.21 +/-0.22 and 1.27 +/-0.15, respectively. However., due to evaporation of water from the aerosols collected on the filter tape of the beta -gauge, differences in PM10 concentrations are much less than theoretically calculated. (C) 2001 Elsevier Science Ltd. All rights reserved.
High-sensitivity microwave vector detection at extremely low-power levels for low-dimensional electron systems
(2004-11-01)
Hsieh, WH
;
Kuan, CH
;
Suen, YW
;
Chang, SY
;
Li, LC
We present a high-sensitivity microwave vector detection system for studying the low-dimensional electron system embedded in the gaps of a coplanar waveguide at low temperatures. Using this system, we have achieved 0.005% and 0.001degrees resolutions in amplitude and phase variations, respectively, at 10 GHz in a magnetotransport measurement on a quantum-wire array with an average signal power less than -75 dBm into the sample at 0.3 K. From the measured phase variation, we can distinguish a very tiny change in the induced dipole moment of each quantum wire. (C) 2004 American Institute of Physics.
Learning search keywords for construction procurement
(2005-01-01)
Dzeng, RJ
;
Chang, SY
;
土木工程學系
;
Department of Civil Engineering
Seeking information from websites has become an essential part of a contractor's procurement undertaking. as more and more procurement websites become available on the Internet, Websites host extremely lame amounts of information: a keyword search, therefore, is often more efficient than browsing via an index. However. in order to find the desired information. it may be necessary to enter keywords using a trial-and-error process. This research recognizes that professional procurement experience can help users search website information more effectively, by using fewer keywords. and so proposes a learning model and suggestion model that can capture such experience. thus guiding inexperienced users in their search. Experiments, evaluating the performance of the system, were also conducted. (C) 2004 Elsevier B.V. All rights reserved.
The fragment transformation method to detect the protein structural motifs
(2006-05-15)
Lu, CH
;
Lin, YS
;
Chen, YC
;
Yu, CS
;
Chang, SY
To identify functional structural motifs from protein structures of unknown function becomes increasingly important in recent years due to the progress of the structural genomics initiatives. Although certain structural patterns such as the Asp-His-Ser catalytic triad are easy to detect because of their conserved residues and stringently constrained geometry, it is usually more challenging to detect a general structural motifs like, for example, the beta beta alpha-metal binding motif, which has a much more variable conformation and sequence. At present, the identification of these motifs usually relies on manual procedures based on different structure and sequence analysis tools. In this study, we develop a structural alignment algorithm combining both structural and sequence information to identify the local structure motifs. We applied our method to the following examples: the beta beta alpha-metal binding motif and the treble clef motif. The beta beta alpha-metal binding motif plays an important role in nonspecific DNA interactions and cleavage in host defense and apoptosis. The treble clef motif is a zinc-binding motif adaptable to diverse functions such as the binding of nucleic acid and hydrolysis of phosphodiester bonds. Our results are encouraging, indicating that we can effectively identify these structural motifs in an automatic fashion. Our method may provide a useful means for automatic functional annotation through detecting structural motifs associated with particular functions.
Thin-film reactions during diffusion soldering of Cu/Ti/Si and Au/Cu/Al2O3 with Sn interlayers
(2003-09-01)
Liang, MW
;
Hsieh, TE
;
Chang, SY
;
Chuang, TH
;
材料科學與工程學系
The multilayer thin-film systems of Cu/Ti/Si and Au/Cu/Al2O3 were diffusion-soldered at temperatures between 250degreesC and 400degreesC by inserting a Sn thin-film interlayer. Experimental results showed that a double layer of intermetallic compounds (IMCs) eta-(Cu0.99Au0.01)(6)Sn(5/)delta-(Au0.87Cu0.13)Sn was formed at the interface. Kinetics analyses revealed that the growth of intermetallics was diffusion-controlled. The activation energies as calculated from Arrhenius plots of the growth rate constants for (Cu0.99Au0.01)(6)Sn-5 and (Au0.87Cu0.13)Sn are 16.9 kJ/mol and 53.7 kJ/mol, respectively. Finally, a satisfactory tensile strength of 132 kg/cm(2) could be attained under the bonding condition of 300degreesC for 20 min.