The growth of Chinese minority populations

The 55 recognized minority races in PRChina have a total population of 91.2 million. These peoples are distributed widely in two–thirds of China's territories.The minority population has grown rapidly since the 1960s. In this paper, I examine the major causes of this growth. They are the significant improvement of public health in the 1950s and 1960s, the leniency in the implementation of the birth control policies in minority communities, the relatively high birth and fertility rates in these communities, and the reaffirmation of racial identity in the 1980s.Most minority settlements are located in the less developed interior of China. Some of these areas are rich in minerals but they are not used most efficiently. Meanwhile, the land is over used. Today the Chinese advocate a faster economic development and a stricter birth control program for these areas.     

Three‐dimensional hydrodynamic and salinity transport modelling of Danshuei River estuarine system and adjacent coastal sea,Taiwan

A three‐dimensional, time‐dependent hydrodynamic and salinity model was applied to the Danshuei River estuarine system and adjacent coastal sea in Taiwan. The model forcing functions consist of tidal elevations along the open boundary and freshwater flows from the main stem and tributaries in the Danshuei River system. The bottom roughness height was calibrated and verified with model simulation of barotropic flow, and the turbulent diffusivities were calibrated through comparison of time‐series of salinity distributions. The overall model verification was achieved with comparisons of residual current and salinity distribution. The model simulation results are in qualitative agreement with the available field data. The model was then used to investigate the tidal current, residual current, and salinity patterns under the low freshwater flow condition in the modelling domain. The results reveal that the extensive intrusion of saline water imposes a significant baroclinic forcing and induces a strong residual circulation in the estuary. The downriver net velocity in the upper layer increases seaward despite the enlargement of the river cross‐section in that direction. Strong residual circulation can be found near the Kuan‐Du station. This may be the result of the deep bathymetric features there. Copyright © 2007 John Wiley & Sons, Ltd.     

Mineralogical and Geochemical Study of Zhaoping,Xifu and Hami Iron Meteorites

The mineralogy and bulk chemical compositions of three iron meteorites (Zhaoping, Xifu and Hami) recently found in China are reported here and are classified on the basis of their bulk chemical compositions. Zhaoping contains 93.4 mg/g Ni, 85.9 μg/g Ga, 418 μg/g Ge, 5.24 mg/g Co, 1.94 μg/g Ir, 0.774 μg/g W, and 1.62 μg/g Au and belongs to the low-Ni, low-Au subgroup of IAB. It is a coarse octahedrite and consists of kamacite, taenite, troilite, schreibersite and cohenite. The cohenite has entirely decomposed to graphite and low-Ni kamacite in our samples. Zhaoping contains some inclusions of Mn-free sarcopside which were rarely reported in IAB iron meteorites. Xifu has 74.1 mg/g Ni, 58.8gμg/g Ga, 150 μg/g Ge, and 0.913 μg/g W. Xifu is a member of group IIICD iron meteorite. Like most of IIICD irons, Xifu is a coarsest octahedrite with kamacite bandwidth larger than 3mm, and contains kamacite, taenite and schreibersite. Carbides and graphite are not found in the sample because of its being heterogeneous. Hami has 106 mg/g Ni, 5.36 mg/g Co and 0.922 μg/g Ir. We did not obtain the Ga and Ge contents in Hami because of their low concentrations and the limited precision of the INAA technique. Hami is an unclassified iron meteorite on the basis of the contents of other trace elements, structure and mineralogy. On mineralogy and structure, Hami resembles Rafruti, another unclassified iron meteorite.     

Photocatalytic degradation of spill oils on TiO2 nanotube thin films

The nitrogen-doped TiO₂ nanotube (N-TNT) thin films were synthesized using ZnO nanorods as the template and doped with urea at 623 K. Under ultraviolet (UV) and visible light irradiation, the efficiencies for photocatalytic degradation of methylene blue is as high as 30%. About 10% of toluene (representing aromatics in the spill oils) in sea water can be photocatalytically degraded under visible light radiation for 120 min. The aliphatic model compound (1-hexadecene) has, on the contrary, a less efficiency (8%) on the N-TNT photocatalyst. On the average, under visible light radiation, the effectnesses of the N-TNT for photocatalytic degradation of model compounds in the spill oils in sea water are 0.38 mg toluene/gN-TNT h and 0.25 mg 1-hexadecene/gN-TNT h. It is expected that spill oils in the harbors or seashores can be adsorbed and photocatalytically degraded on the N-TNT thin films that are coated onto levee at the sea water surface level.     

Using ADV backscatter strength for measuring suspended cohesive sediment concentration

Laboratory experiments were conducted at two institutes to reveal the relationship between acoustic backscatter strength and suspended sediment concentration (SSC). In total, three acoustic Doppler velocimeters (ADVs) with different frequencies (5, 10 and 16 MHz) were tested. Two different commercial clays and one natural sediment from Clay Bank site in the York River were checked for acoustic responses. The SSCs of selected sediments were artificially changed between a selected low and a high value in tap or de-ion water. Each ADV showed quite different backscatter responses depending on the sediment type and SSC. Not all devices had a good linear relationship between backscatter strength and SSC. Within a limited range of SSC, however, the backscatter strength can be well correlated with the SSC. Compared with optical backscattering sensor (OBS), the fluctuation of ADV backscatter signals was too noisy to be directly converted to the instantaneous changes of SSC due to high amplification ratio and small sampling volume. For the more accurate signal conversion for finding the fluctuation of SSC, the ensemble average should be applied to increase the signal-to-noise ratio. There are unexpected responses for the averaged backscatter wave strength: (1) high signals from small particles but low signals from large particles; and (2) two linear segments in calibration slope. These phenomena would be most likely caused by the different gain setting built in ADVs. The different acoustic responses to flocculation might also contribute somewhat if flocs are tightly packed. This study suggests that an ADV could be a useful instrument to estimate suspended cohesive sediment concentration and its fluctuation if the above concerns are clarified.     

Core-log integration studies in hole-A of Taiwan Chelungpu-fault Drilling Project

Taiwan Chelungpu-fault Drilling Project (TCDP) was initiated to understand the physical mechanisms involved in the large displacements of the 1999 Taiwan Chi-Chi earthquake. Continuous measurements of cores (including laboratory work) and a suite of geophysical downhole logs, including P - and S -wave sonic velocity, gamma ray, electrical resistivity, density, temperature, electrical borehole images and dipole-shear sonic imager, were acquired in Hole-A over the depth of 500–2003 m. Integrated studies of cores and logs facilitate qualitative and quantitative comparison of subsurface structures and physical properties of rocks. A total of 10 subunits were divided on the basis of geophysical characteristics. Generally, formation velocity and temperature increase with depth as a result of the overburden and thermal gradient, respectively. Gamma ray, resistivity, formation density, shear velocity anisotropy and density-derived porosity are primarily dependent on the lithology. Zones with changes of percentage of shear wave anisotropy and the fast shear polarization azimuth deduced from Dipole Shear-Imager (DSI) are associated with the appearance of fractures, steep bedding and shear zones. The fast shear wave azimuth is in good agreement with overall dip of the bedding (approximately 30° towards SE) and maximum horizontal compressional direction, particularly in the Kueichulin Formation showing strong shear wave velocity anisotropy. Bedding-parallel fractures are prevalent within cores, whereas minor sets of high-angle, NNW–SSE trending with N- and S-dipping fractures are sporadically distributed. The fault zone at depth 1111 m (FZA1111) is the Chi-Chi earthquake slip zone and could be a fluid conduit after the earthquake. The drastic change in fast shear wave polarization direction across the underlying, non-active Sanyi thrust at depth 1710 m reflects changes in stratigraphy, physical properties and structural geometry.     

Modelling of hydrodynamics and cohesive sediment transport in Tanshui River estuarine system,Taiwan

A laterally averaged two-dimensional numerical model is used to simulate hydrodynamics and cohesive sediment transport in the Tanshui River estuarine system. The model handles tributaries as well as the main stem of the estuarine system. Observed time series of salinity data and tidally averaged salinity distributions have been compared with model results to calibrate the turbulent diffusion coefficients. The overall model verification is achieved with comparisons of residual currents and salinity distribution. The model reproduces the prototype water surface elevation, currents and salinity distributions. Comparisons of the suspended cohesive sediment concentrations calculated by the numerical model and the field data at various stations show good agreement. The validated model is applied to investigate the tidally averaged salinity distributions, residual circulation and suspended sediment concentration under low flow conditions in the Tanshui River estuarine system. The model results show that the limit of salt intrusion in the mainstem estuary is located at Hsin-Hai bridge in Tahan Stream, 26 km from the River mouth under Q75 flow. The null point is located at the head of salt intrusion, using 1 ppt isohaline as an indicator. The tidally averaged sediment concentration distribution exhibits a local maximum around the null point.     

Design of a high performance variable structure position control ofROVs

An adaptive control scheme for dynamic positioning (DP) of remotely operated underwater vehicles (ROV) is proposed based on a recently developed output feedback variable structure control (VSC) algorithm named VS-MRAC. Only position measurement is required. Precise modeling of the ROV is not needed and unmodeled perturbations can be effectively rejected. A simple method for discretizing the original continuous-time VS-MRAC is proposed based on dead-beat response. Other important practical implementation issues are considered. The performance is evaluated by simulation with a realistic ROV model and by full-scale experimental pool tests with an actual ROV     

Locational Decisions and Residential Preferences of Taiwanese Immigrants in Australia

Since the 1980s, the increase of Asian migrants in large cities has contributed significantly to the cultural landscape of Australia, especially in the city suburbs. Based on the Census and in-depth interviews of 103 Taiwanese migrants, this research examines the location decisions and residential preferences of Taiwanese migrants in Sydney, Brisbane and Melbourne. The reasons for choosing the state, the particular city, and specific area of residence are probed into. The survey shows that migrants moved to Australia mainly for children’s education, lifestyle and political instability reasons. The main reasons for choosing to settle in Sydney were favourable business opportunities, and the northern part of Sydney was preferred. Those who chose Brisbane are attracted by the good climate there, and the residents preferred the Sunnybank area. Melbourne was chosen for the good education it offers, and areas on transportation lines near good schools are selected. Choice of residence was based mainly on their needs and their resources which may change over time. In general, they always choose to locate in close proximity to their family, friends and Taiwanese communities. Their locational choice depends on income and housing budget, proximity to good schools and shopping centers, and information from friends or earlier migrants. Based on such factors, this study clearly demonstrates that the Taiwanese immigrants are fundamentally different from early Chinese settlers who once aimed to settle at Chinatown locations.