S U M M A R YThe Taipei basin in northern Taiwan is located in a high seismicity region and was affected by several earthquakes in the past (M L = 7.3 on 1909 April 15; M L = 6.8 on 1986 November 15; the Chi-Chi M L = 7.3 earthquake on 1999 September 21 and M L = 6.8 on 2002 March 31). The main characteristic of the Taipei basin is its complex shape with a deep western and shallow eastern part. The uppermost Sungshan formation with its low shear wave velocities (90-200 m s −1 ) is also a distinct feature of the basin. Based on the large data base of earthquake records obtained from the Taiwan Strong Motion Instrumentation Program network, many studies on ground motion within the Taipei basin exist. However, the influence of the various subsurface structures on the observed ground motions as well as the variability of ground motion with respect to earthquake location is not fully understood. We apply a 3-D finitedifference method to simulate wave propagation up to 1 Hz for a small earthquake close to the basin in order to resolve these open questions. By varying source and structural parameters, we explore the variability of ground motion.Our study includes a subsurface model that is based on recent studies on the basin structure and on the crustal structure of Taiwan. From our simulations we find a good fit between simulated and observed waveforms and peak ground accelerations for the considered small earthquake near the basin. We also explore the influence of fault plane orientation, hypocentre location, deep basin structure and soft soil surface layers of the Sungshan formation by varying the subsurface structure and earthquake position. Our studies reveal that the basin structure produces an amplification factor of about 4 compared to hard rock conditions. Additionally, the soft soil Sungshan formation produce amplification of a factor of 2. This results in a maximum amplification of the basin structure of about 8, which is in good comparison with amplification values larger than 5 found from the analysis of observed earthquakes. These values clearly exceed the amplification values of about 2-3 obtained when applying standard 1-D site effect analysis.Our simulations for different earthquake positions show that ground motion depends strongly on earthquake location and fault orientation. Therefore, the application of average values of spectral amplification obtained from the analysis of recorded data from distant earthquakes with different azimuths and fault planes may significantly underestimate future ground motions of possible earthquakes on known faults close to the Taipei basin. The simulation of a small earthquake near the Taipei basin presented in this study will help to set up adequate simulation parameters for a possible large earthquake close to the Taipei basin. Such a simulation of a scenario earthquake close to the Taipei basin would allow to significantly improve hazard assessment as no observations of strong earthquakes in the vicinity of the basin exist.

Chitin [poly-(N-acetyl-1,4-beta-D-glucopyranosamine)] microcapsules were prepared by the simple desolvation and the non-solvent addition phase separation methods. In the simple desolvation method, chitin droplets were dropped into the desolvation agent (water, ethanol, or acetone) and microcapsules soon formed. Several solvent-nonsolvent pairs: N,N-dimethylacetamide (DMAc)-water, DMAc-ethanol, DMAc-propanol, DMAc-n-butanol, and DMAc-acetone with different solubility parameter difference, (delta delta) were chosen to prepare chitin microcapsules containing 6-mercaptopurine by using the non-solvent-addition phase separation method. The results showed that the surface morphology and release behaviour of the microcapsules were greatly affected by different solvent-nonsolvent pairs. The surface of microcapsules prepared from the system of high delta delta was more smooth than those from the systems of low delta delta. The drug content using the simple desolvation method increased with decreasing delta delta because of the higher film formation rate of the microcapsules. On the other hand, the drug content using the nonsolvent addition method was lower than that using the simple desolvation method because of the dispersion forces, applied by mechanical stirring. Microcapsules prepared by the simple desolvation method had a narrower size distribution and larger mean size than those prepared by the nonsolvent addition method.