Showing papers by "Sun Yat-sen University published in 1995"

International Human Resource Strategy and Its Determinants: The Case of Subsidiaries in Taiwan

Abstract: This paper explores how the tension between global integration and local responsiveness affects the dimensions and determinants of international human resource (IHR) strategy. To accomplish this, Jarillo and Martinez's [1990] business strategy framework for parents and their subsidiaries was recast in an IHR strategy setting. Then, the relationships between the two dimensions of IHR strategy that emerged, global integration and local responsiveness, and a set of interorganizational interdependency variables were explored. Several new and informative associations between the interorganizational interdependency variables (subsidiaries' dependence on parent's resources, local resources, and hot institutions) and IHR strategy were observed in a sample of one hundred subsidiaries of Japanese, U.S. and European MNCs operating in Taiwan.

Lattice-parameter variation with carbon content of martensite. I. X-ray-diffraction experimental study.

Abstract: An experimental law of the x-ray diffraction of polycrystalline martensite is found, which is satisfactorily explained from x-ray-diffraction theory. The experimental phenomenon is well consistent with the hypothesis that at low carbon content martensite is of cubic structure. The cubic-tetragonal transition of martensite concerned with the distribution of carbon atoms is observed, and an experimental critical point of the transition is also obtained. Dependences of the lattice parameter of low-carbon martensite upon carbon content are established. With the dependences, it becomes possible to determine the carbon content of the carbon-supersaturated \ensuremath{\alpha}-phase of steel.

Nutrients and heavy metal contamination of plants and sediments in Futian mangrove forest

Abstract: An ecological survey was carried out to determine the levels of nutrients and heavy metals in the sediments and leaf tissues of two dominant mangrove plant species, Kandelia candel and Aegiceras corniculatum, in Futian mangrove forest, Shenzhen, the People's Republic of China. The spatial and seasonal variations of these elements were also investigated. The results show that there was no major difference between two sampling sites 150 m apart. In both sites, the sediment concentrations of total and NH4 +-N, total and extractable P, total and extractable K, total organic carbon were consistently higher in the landward locations and decreased gradually towards the sea. The sediment sample collected at the seaward edge of the mangrove plant community had the lowest levels of nutrient and organic matter. The vertical variations (from the land to the sea) of sediment heavy metals were less obvious and no particular trend could be identified. Extremely high contents of Cu, Cd, Pb, Cr and Zn were found at certain locations, suggesting the occurrence of some local contamination. The mean total metal concentrations in sediments decreased in the order Mn > Zn > Cu > Cr = Pb > Cd for the sample locations. Most of the heavy metals were not in a bioavailable form as the concentrations of extractable metals were relatively low (< 1% of total metals). Pb, Cr and Cd were not detected in leaf samples. Leaf C, N, P and K contents were similar between the two species and no significant difference was found among locations, although A. corniculatum seemed to have lower Mn concentrations than K. candel. With reference to temporal variations, no significant difference in sediment concentrations of some nutrients and metals was found between the spring and autumn seasons.

Application of sciatic functional index in nerve functional assessment

Abstract: In order to confirm the reliability of the sciatic functional index (SFI) in the rat, SFI, muscle strength, electrophysiological, and morphometric assessments were carried out from the 10th day to the sixth month after nerve injury or repair. The results showed that the SFI has a positive correlation with all tested indices of muscle strength, electrophysiology, and morphology (r = 0.925-0.996, P < 0.01 or P < 0.001). These results indicate that the SFI is a reliable index for evaluating rat sciatic nerve regeneration and can be widely used.

Effect of wastewater discharge on nutrient contamination of mangrove soils and plants

Abstract: The ecological impact of sewage discharges to a mangrove wetland in Futian National Nature Reserve, the People’s Republic of China was assessed by comparing the plant community, plant growth and nutrient status of soils and vegetation of a site treated with settled municipal wastewater (Site A) with those of a control adjacent site (Site B) which did not receive sewage. During the one year study, the total and available N and P, and organic carbon concentrations of mangrove soils in Site A did not significantly differ from those of Site B. In both sites, the soil organic C, total N, NH 4 + -N and total P content exhibited a descending trend from landward to seaward regions, with the lowest measurements obtained from the most foreshore location. Seasonal variation in N content of soil samples was more obvious than any difference between wastewater treated and the control sites. The soil N content was lower in spring and summer. This was attributed to the higher temperature in these seasons which facilitated degradation of organic matter and absorption of nitrogen by the plants for growth. No significant difference in plant community structure, plant growth (in terms of tree height and diameter) and biomass was found between Sites A and B. Leaf samples of the two dominant plant species, Kandelia candel and Aegiceras corniculatum collected from Site A had comparable content of organic carbon, N, P and K to those of Site B. These preliminary results indicated that the discharge of a total volume of 2600 m3 municipal wastewater to an area of 1800 m2 mangrove plants over the period of a year did not produce any apparent impact on growth of the plants. The soils and plant leaves of Site A were not contaminated, in terms of nutrient content, by the discharged sewage.

Community structure and standing crop biomass of a mangrove forest in Futian Nature Reserve, Shenzhen, China

Abstract: The community structure and standing crop biomass of a mangrove forest in Futian Nature Reserve, Shenzhen, the People’s Republic of China was studied. This mangrove, located towards the northern latitudinal limit of the mangrove development (22°N), had relatively simple structure and low diversity (the Shannon-Wiener index was 0.78). The three dominant species, namely Aegiceras corniculatum, Kandelia candel and Avicennia marina, possess importance values of 72, 19 and 9%, respectively. The average height of the mangrove community was 4.5 m with no vertical stratification. The values of tree density of A. corniculatum and A. marina were found to be 5290 and 260 ha−1, respectively. The biomass of both A. corniculatum and K. candel was best estimated from regression equations using a combination of height and diameter at breast height as the independent variables. For Avicennia marina, there was no simple correlation between biomass and height or diameter. The regression models suggested by previous workers did not give satisfactory estimation of biomass of A. marina in this mangrove forest. The total biomass of this mangrove forest was 12.1 kg m−2, with 73% of such production contributed by A. corniculatum and 8% by A. marina. Because of its small percentage, the inaccuracy in estimating biomass of A. marina did not affect the overall determination of biomass of the whole community. Average above-ground biomass was 8.7 kg m−2 (72% of the total biomass) and the major components were aerial woody tissues, stems and branches. The rootshoot ratio of this plant community was 0.4:1.

The social space of guangzhou city, china

Abstract: Principal components analysis and cluster analysis we used to analyze the urban social spatial structure of socialist China, using the city proper of Guangzhou in 1984 as the study area. Unlike the urban social spatial structure in Western cities, which are commonly differentiated by socioeconomic status, family status, and ethnicity, it was found that the main components of social space in Guangzhou are population density, educational level, employment, housing quality, and household composition. Five types of social areas are identified: (i) high density, mixed function areas, (2) cadre (government worker) areas, (3) worker areas, (4) intellectual areas, and (5) scattered agricultural areas. The spatial pattern of the social areas of Guanghou has a concentric elliptical shape. The city is composed of a high-density, mixed-function center surrounded by consecutive rings of workers' residences and agricultural land, with a cadre sector abutting the northeastern edge of the city center and two intelectual ...

Dissipation function of the first-order phase transformation in solids via internal-friction measurements

Abstract: Reconstruction and displacement of crystal structure and motion of the phase interface induces dissipation of energy, and latent heat appears during a first-order phase transition (FOPT) in solids. In this series of investigations, we first express the energy dissipation as a function of four physical parameters. Since there are more unknowns than the number of equations, we introduce four more equations describing the dynamics of the system on which internal friction (IF, the dissipation of vibration energy) measurements are conducted. Via IF measurements during FOPT, we can then calculate the relevant four parameters and hence the dissipation function. We have completed the first step in establishing a phenomenological theory to describe FOPT in solids.

Helicobacter pylori associated with a high prevalence of duodenal ulcer disease and a low prevalence of gastric cancer in a developing nation.

Abstract: This study examines the relationship between Helicobacter pylori infection and peptic ulcer disease and gastric cancer--in particular, the presence or absence of bacteria, the grading of gastritis, and the degree of inflammation in the antral and oxyntic mucosae. The grading of gastritis and the detection of H pylori were determined by histology using the Sydney system. Of the 1006 patients examined, 34.5% had duodenal ulcer disease, 3.5% gastric ulcer disease, and 2% with coexistent ulceration. Most patients (50.2%) were classified as having non-ulcer dyspepsia. Altogether 2.4% of patients had gastric cancer and two further patients had carcinoma in the gastric stump. Of the ulcer disease patients, 87.2% had histological evidence of H pylori infection. After patients who had taken antibiotics or bismuth compounds in the preceding four weeks were excluded, 98.9% of the duodenal ulcer disease, 100% of the gastric ulcer disease, and 100% of the coexistent ulcer disease patients had evidence of H pylori infection. In patients with gastric cancer who had not taken antimicrobial agents in the four weeks before endoscopy, 83.3% had evidence of H pylori infection. Thus, there was a high rate of duodenal ulcer disease and a low rate of gastric ulcer disease in southern China, an area of low gastric cancer mortality. There was a specific topographical relationship between H pylori, the histological response, and gastroduodenal disease. Our data suggest that the status of a nation as either 'developed' or 'developing' can not be used to predict the upper gastrointestinal disease profile of its population.

Fractal approach to the critical filler volume fraction of an electrically conductive polymer composite

Abstract: It has been known for quite a long time that polymers filled with electrically conductive particles, foils or fibres exhibit a distinctive dependence of conductivity on filler volume fraction. With a rise in filler content, there is always a drastic increase in composite conductivity by the order of ten magnitudes at a certain threshold, namely, the critical volume fraction. Such a transition-like change in conductivity is usually interpreted as percolation. Many models have been proposed for explaining the conduction mechanism involved, but often they possess evident drawbacks mainly due to the negligence of relative filler arrangements or the Euclidean geometric description of the arrays. The present work focused on the prediction of the critical volume fraction by a new electrical conductive model, based on the fractal technique and the generalized unit-cell method proposed by Pitchumani and Yao for modelling the thermal conductivity of fibrous composites. It was found that the electrical conduction behaviour of a polymer composite is governed by both a filler geometry factor and a material factor of the components. The critical volume fractions estimated by the model are in good agreement with experimental results taken from the literature. In addition, possible improvements of the present approach are discussed.

Effect of synthetic wastewater on young Kandelia candel plants growing under greenhouse conditions

Abstract: A greenhouse experiment was performed to evaluate the effects of synthetic wastewater in three different strengths, NW, MW and CW, on the growth of the one-year old Kandelia candel (L.) Druce plants. NW had the characteristics and strength similar to natural municipal wastewater while MW and CW contained five and ten times of the nutrients and heavy metals in NW, respectively. Artificial seawater was used as the control. During one year wastewater treatment experiment, Kandelia were found to withstand wastewater of high strength and toxic symptoms were not detected in all plants. Synthetic wastewater with strength similar to the natural municipal sewage (NW) stimulated plant growth. The plants treated with NW had significantly higher aerial and root biomass, taller stem than those found in the CW, MW and the control. Maximum growth, in terms of both stem height and total biomass, of all plants occurred in summer months, from June to September. With respect to the physiological and biochemical activities, CW and MW treated plants had significantly lower levels of chlorophyll a, total chlorophyll and catalase activity than those found in NW and control groups. In contrast, the proline content of plants treated with wastewater was similar to that of the control. These results suggest that normal wastewater (NW), attributed to its nutrients and trace elements, enhanced plant growth. The medium (MW) and concentrated wastewater (CW) supported similar amount of plant growth as the control but the physiological and biochemical parameters indicate that these treated plants might have been exposed to some kind of stress, probably due to the excess heavy metals present in MW and CW.

Lattice-parameter variation with carbon content of martensite. II. Long-wavelength theory of the cubic-to-tetragonal transition.

Abstract: Based on the experimental observation of cubic-to-tetragonal transition of low-carbon martensite, we perform a long-wavelength approximation for the stress-induced elastic interaction in the theory of microscopic elasticity. Taking into account the elastic anisotropy and the tetragonal character of the octahedral interstices in \ensuremath{\alpha}-iron, we consistently obtain the cubic-to-tetragonal transition of first-order nature at the carbon concentration of 0.18 wt %, using the order-disorder transition theory formulated by Khachaturyan with the method of static concentration waves. The detailed variation of the lattice parameters and axial ratio is also given compatibly with our results. The difference in experimental results between single crystals and polycrystals is emphasized, and a phenomenological two-dimensional internal strain is proposed to explain the transition in thin-plate samples. The results are in good agreement with experimental observations.

Renormalization Group Theory of Hysteresis.

Abstract: We apply renormalization group theory directly to the first-order phase transition of the large-N model driven linearly by an external magnetic field $H\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}\stackrel{\ifmmode \dot{}\else \.{}\fi{}}{H}t$, where $\stackrel{\ifmmode \dot{}\else \.{}\fi{}}{H}$ is the sweeping rate. Novel dynamic scaling forms for the magnetization, the structure factor, and the area of hysteresis loop are $M(\stackrel{\ifmmode \dot{}\else \.{}\fi{}}{H},t,T)\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}f({\stackrel{\ifmmode \dot{}\else \.{}\fi{}}{H}}^{1/2}t,{\stackrel{\ifmmode \dot{}\else \.{}\fi{}}{H}}^{(d\ensuremath{-}2)/4}T)$, $C(k,\stackrel{\ifmmode \dot{}\else \.{}\fi{}}{H},t,T)\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}{\stackrel{\ifmmode \dot{}\else \.{}\fi{}}{H}}^{\ensuremath{-}d/4}{f}^{\ensuremath{'}}({\stackrel{\ifmmode \dot{}\else \.{}\fi{}}{H}}^{\ensuremath{-}1/4}k,{\stackrel{\ifmmode \dot{}\else \.{}\fi{}}{H}}^{1/2}t,{\stackrel{\ifmmode \dot{}\else \.{}\fi{}}{H}}^{\left(d\ensuremath{-}2\right)/4}T)$, and $A\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}{\stackrel{\ifmmode \dot{}\else \.{}\fi{}}{H}}^{1/2}g({\stackrel{\ifmmode \dot{}\else \.{}\fi{}}{H}}^{\left(d\ensuremath{-}2\right)/4}T)$, respectively, where $T$ is the temperature of the system, $d$ the spatial dimensionality, $k$ the wave number, and $f$, ${f}^{\ensuremath{'}}$, and $g$ scaling functions. These results show that the rate of the external driving field can serve as a scaling parameter to study hysteresis.

High-pressure synthesis of single-phase superconductors HgzSrxBa2−xCa2Cu3O8+δ and (Hg, M)Sr2Ca2Cu3Oy with MPb and Mo

Abstract: The recent observation of superconductivity above 160 K under high pressures has prompted us to investigate the possibility of retaining such high-temperature superconductivity at ambient pressure by substituting Sr for Ba in HgBa 2 Ca 2 Cu 3 O 8 (Hg-1223). High-purity (≥90%) Hg-1223 phase samples were synthesized with a nominal composition of Hg z Sr x Ba 2− x Ca 2 Cu 3 O 8+δ (where z =0.75 and x =0, 0.5 or 1). By adding a second element, Pb or Mo, supposedly to the Hg site, (Hg,Pb/Mo)Sr 2 Ca 2 Cu 2 O 8+δ with purity up to 90% was achieved. Unfortunately, T c decreases with Sr substitution. The roles of Sr in the phase stability, and the synthesis conditions of the Sr based Hg-1223, and the Sr substitution effect on the T c of these samples will be discussed.

Precursor effects on HgBa2Ca2Cu3O8 formation under high pressure

Abstract: The effects of the precursor on the synthesis of HgBa 2 Ca 2 Cu 3 O 8+δ (Hg-1233) under high pressure are studied. It was observed that HgCaO 2 and Hg-1212 appear in the early stage of the formation of Hg-1223. Through intercalation of BaCuO and CaCuO, HgCaO 2 and Hg-1212 can be converted to Hg-1223. We found that the mixing level of Ca- and Cu-ions strongly affects the formation of Hg-1223. The existence of large CaO grains in the precursor will increase the needed synthesis temperature or synthesis time, and impurities may appear. A precursor in which Ca-ions are well reacted with other ions facilities the formation of Hg-1223. We also found that this well-reacted precursor is insensitive to moist air.

Local fields in single-mode helical fibres

Abstract: The scalar local-field wave equations in helical fibres are derived and, with the aid of a special mathematical treatment, solved approximately in a local coordinate system—the Serret-Frenet frame from the Maxwell's equations. Two basic results are obtained: (1) The local modes in a single-mode helical fibre are circularly polarized. (2) The difference of the propagation constants between the two fundamental modes is 2τ, where τ is the torsion. They agree well with the known experimental measurements.

Nutrients and Heavy Metal Contamination of Plants and Sediments in Futian Mangrove Forest

Abstract: An ecological survey was carried out to determine the levels of nutrients and heavy metals in the sediments and leaf tissues of two dominant mangrove plant species, Kandelia candel and Aegiceras corniculatum, in Futian mangrove forest, Shenzhen, the People’s Republic of China. The spatial and seasonal variations of these elements were also investigated. The results show that there was no major difference between two sampling sites 150 m apart. In both sites, the sediment concentrations of total and NH 4 + -N, total and extractable P, total and extractable K, total organic carbon were consistently higher in the landward locations and decreased gradually towards the sea. The sediment samples collected at the seaward edge of the mangrove plant community had the lowest levels of nutrient and organic matter. The vertical variations (from the land to the sea) of sediment heavy metals were less obvious and no particular trend could be identified. Extremely high contents of Cu, Cd, Pb, Cr and Zn were found at certain locations, suggesting the occurrence of some local contamination. The mean total metal concentrations in sediments decreased in the order Mn > Zn > Cu > Cr = Pb > Cd for the sample locations. Most of the heavy metals were not in a bioavailable form as the concentrations of extractable metals were relatively low (< 1% of total metals). Pb, Cr and Cd were not detected in leaf samples. Leaf C, N, P and K contents were similar between the two species and no significant difference was found among locations, although A. corniculatum seemed to have lower Mn concentrations than K. candel. With reference to temporal variations, no significant difference in sediment concentrations of some nutrients and metals was found between the spring and autumn seasons.

CHINESE URBAN GEOGRAPHY SINCE THE LATE 1970s

Abstract: Economic reforms and the opening of China to the outside world beginning in the late 1970s have provided the impetus for increased research in urban geography. Major research themes have included urbanization (including rural to urban migration and control of city size), national and regional urban systems, and urban morphology and internal spatial structure. Topics for further investigation in the future should include the effects of a land market, urban sprawl, and the problems resulting from the shift to a market-oriented economy.

Superradiance of High Density Frenkel Excitons at Room Temperature.

Abstract: Superradiance of high density Frenkel excitons in an $R$-phycoerythrin single crystal is observed at room temperature for the first time. No fluorescence is observed except the emission at the sharp exciton band when the superradiance of excitons occurs, and the higher the pump density, the sharper the emission bandwidth. A redshift and a blueshift are observed at the rise time and the fall time of the emission pulse, respectively. The experimental results also imply deformed-boson properties of high density Frenkel excitons.

A new cytotoxic dihydroxy sterol from the soft coral Alcyonium patagonicum.

Abstract: A new sterol, 24-methylenecholest-4-ene-3 beta,6 beta-diol [1] was isolated from the soft coral Alcyonium patagonicum collected from the South China Sea. Its structure was determined by spectral analysis. Compound 1 was cytotoxic against the P-388 cell line with an IC50 value of 1 microgram/ml.