Nacrite and dickite are found in two localities in northern Taiwan. One, containing nacrite and dickite, is associated with a gold-enargite deposit as a vug-filling clay in the Chinkushih (CKS) mine district near the northern coast. The other is the occurrence of dickite in the interstices of a Miocene coarse-grained quartzose sandstone in the Nanshihchiao (NSC) area, near Taipei city. X-ray diffraction (XRD), differential thermal analysis (DTA), scanning electron microscope (SEM), and petrographic examinations were used to characterize the mineralogical features. Nacrite most often takes the unusual form of rhombic platelets, and dickite is commonly elongated in habit with the shapes possibly related to their origin. Based on geological evidence, we believe that both nacrite and dickite are of hydrothermal origin. In the CKS area, the formation of nacrite and dickite is related to the hypogene gold-enargite mineralization. In contrast, the transformation of dickite in the NSC area is due to the influence of the raised temperatures of sandstone formation, resulting from volcanic activity during the Kungkuan stage after the deposition of the sandstone.

The iron-rich calcareous soil (Typic Rhodustalf) from the Penghu island group represents a volcanic area. The black soils (Typic Haplustert, Vertic Endoaquoll, Typic Hapludolls) are typical of eastern Taiwan. Four A horizons and a pedon from the iron-rich calcareous soil and four pedons from the black soils were studied to analyze soil properties and clay compositions. The objective was to compare the properties of smectites developed from different parent materials. The materials were studied by using conventional X-ray diffraction (XRD) of K- and Mg-saturated clays and involved the alkylam-monium (C = 12) method and the Greene-Kelly test. The mean-layer charge of smectites (0.48–0.52 cmol(c)/O10(OH)2) in the iron-rich calcareous soil was found to be higher than the black soils (0.43–0.48 cmol(c)/O10(OH)2). A smectite of higher charge developed from the basalts. This smectite is enriched in Fe and Mg, and lacks Si, thereby forming beidellite and/or nontronite. In contrast, under high precipitation, elevated temperature, base saturation (e.g., Na, K, Ca, Mg), and about equal wet and dry cycles per year in the black soil environments, smectites developed from the complicated geologic site of eastern Taiwan. These smectites transformed to smectite-kaolinite mixed-layer clay and thus, resulted in lower-charge smectites. The K fixation capacity of the iron-rich calcareous soil was higher than the black soils.

Clay mineral compositions from 2 paleosol profiles (Chu-Wan, CW, and Shiao-Men Yu, SMY, profiles) on the late-Miocene sediments in Penghu Islands (Pescadores), Taiwan, are characterized by random X-ray powder diffraction (XRD) and transmission electron microscopy (TEM). By the clay assemblage of the paleosol profile, we want to explore the probable formation mode of the Penghu paleosols.

The paleosol profiles in study are overlain by a layer of basalt flow. However, the clay mineralogy of the 2 paleosols was not altered metasomatically after burial. Results show that 3 distinctive zones of different dominating kaolin-group minerals are apparent in the profiles. In descending order, they are: 1) spheroidal, hollow 7Å-halloysite, 2) platy, irregular-shaped and disordered kaolinite, and 3) platy, irregular-shaped, disordered kaolinite. The relative crystallinity of kaolin minerals of the 3 layers is: layer 2 > layer 3 > layer 1. On the basis of the XRD, TEM analyses and the crystallinity calculations, the distribution of kaolin in Penghu paleosol profiles appears to be unique. Penghu paleosol profiles show systematic change in kaolin crystallinity and polymorphs with depth. Because the clay type is heterogeneous within the profile, this represents that Penghu paleosol profiles were polypedogenic.

The contact between the upper basalt and the paleosol is the erosion surface, so we do not know exactly what the thickness of the original paleosol was. The first layer (about 20 cm) of the profiles appears to be constituents of the original paleosol. It contains high contents of pedogenic (in situ weathering) hematites and 7Å-halloysites, which implies that the local climate of the Penghu Islands at late Miocene was warm and humid. Intense leaching and dry/wet cycle should be the reason for high contents of halloysite (>60%) in the Penghu paleosols. Laterization was the probable pedogenic process for the formation of the paleosols.

Chinmen Island is located in the west of the Taiwan Strait, 15 km from the coast of mainland China. Mesozoic granitic gneiss forms the basement rocks of the island. High-defect kaolin deposits, both major sedimentary and minor residual types of clays, have been mined for ceramic uses for many years. The objectives of this study were to characterize the kaolin deposits and to discuss the genesis of kaolin minerals on the island. The kaolin samples were characterized by X-ray diffraction and transmission and scanning electron microscopy. In general, the particle-size distribution of the sedimentary kaolin was 0.5–5.0% sand, 15–55% silt and 30–85% clay. In the clay fraction, the ratio of kaolinite to illite ranged from 9:1 to 3:1. The sedimentary kaolin materials were originally transported by river from mainland China. Kaolinite occurred generally as pseudo-hexagonal platelets of ∼1 µm in diameter. The residual kaolin minerals resulted from the argillization of granitoid rocks by in situ weathering which possibly occurred during the Pleistocene. The residual kaolin contained more tubular halloysite.

The purposes of this study were: (1) to review the preparation and characterization of the intergrowth between goethite and hematite crystals; and (2) to propose a schematic diagram of the epitaxial relationships among three sets of (100) goethite twin crystals associated with the (001) orientation of the hexagonal prism of hematite. The Fe(ClO4)3 solution was prepared and aged at 70°C, which precipitated goethite initially and produced hematite later with prolonged aging. Goethite and hematite aged for 20 days were observed as star-shaped and hexagonal prisms, respectively. The results suggest that hematite could form later using goethite as a template surface. A selected area electron diffraction (SAED) pattern showed the epitaxial relationship among three sets of (100) goethite intergrowth crystals and hexagonal prisms with the (001) orientation of hematite. Goethite can be produced as lath-, X-, K-, or star-shaped crystals on the (100) orientation, depending on the Fe(ClO4)3 concentrations and the addition of HClO4 to Fe solution samples which were aged for a prolonged period at room temperature. The initial solubility products [(Fe3+)(OH–)3] of the sample solution, rather than the nature of the nuclei, are the key factors governing the formation of goethite or hematite. The addition of acids and high concentrations of iron solutions extend the secondary hydrolysis and induction period (IP) and favor the formation of hematite. The index of the SAED pattern of the star-shaped goethite intergrowth twin crystal has a (100) plane parallel to this basal plane and rotates at a 60° angle between two or three sets of lath-shaped goethite crystals, which share the (011) plane and form goethite twins with ‘interpenetrated’ crystal growth. Stereoscopic viewing using Oak Ridge Thermal Ellipsoid Plot (ORTEP) and CrystalMaker software was deployed to explore the relationship and configuration of oxygen atoms between pseudo-hexagonal (100) goethite associated with hexagonal (001) hematite lattice planes. A schematic diagram of the epitaxial relationship between star-shaped (100) goethite, which is acting as a template facilitating later precipitation of (001) hexagonal prisms of hematite on it, is presented.

Lithiophorite is a naturally occurring phyllomanganate which has been identified in soils and ores. Studies on a synthetic version have shed light on the conditions required for the formation of lithiophorite. In this study, we successfully prepared lithiophorite under highly alkaline conditions. In addition, we found that Li+, Al3+ and hydrothermal treatment are all necessary for the formation of lithiophorite. Lithiophorite, birnessite and Li-intercalated gibbsite were examined by infrared (IR) spectroscopy. The Mn oxide sheets of lithiophorite and birnessite were found to have quite similar structural environments. On the other hand, the LiAl2(OH)6 sheets are affected more markedly by the Mn oxide sheets. After intercalation, the symmetry of the six interlayer OH groups of LiAl2(OH)6 is reduced and they are divided into two groups occupying different sites, corresponding to the IR absorption bands at 3480 and 3312 cm−1, respectively.

Electro-osmotic chemical treatment is an innovative method to improve the strength of soft clays for geotechnical engineering purposes; the effectiveness of the treatment may be related to treatment time, the concentration of the solutions injected, and to variation of pH in the clay. The objective of this study was to investigate the relationship between the above-mentioned factors and the improvement in strength when calcium chloride solution was used as an injection material. A series of tests was carried out by injecting different concentrations of calcium chloride solution into a kaolin suspension, for different treatment times, during electro-osmosis. After the tests, the pH, cone resistance, water content, and concentration of Ca2+ in the kaolin at different locations were measured and analyzed. The results show that the concentration of Ca2+ in the kaolin, the pH, and the strength were increased near the cathode with increases in concentration of CaCl2 and treatment time. An insignificant increase in strength, due to ion exchange over the entire specimen, for short treatment times of 2 to 24 h, was observed because of a small increase in concentration of Ca2+ and in pH. During long-term treatment (120 h), a considerable increase in concentration of Ca2+ (137.0 mg/g) and pH (pH = 10) was observed near the cathode. This led to a pozzolanic reaction, which in turn caused a significant increase in the mechanical strength of the kaolin.

The Tuluanshan Formation of the eastern Coastal Range of Taiwan overlies an andesitic core complex presumed to be the source of hydrothermal fluids responsible for the Si- and Mg-rich mineralization of sepiolite and palygorskite (attapulgite) which are found in veins within fissures and in fracture zones of the volcanic rocks of the region. This study was undertaken in order to understand these relationships better by characterizing sepiolite and palygorskite in this Formation and by examining their occurrence and distribution in the Tungho (TH) and Chunjih (CJ) areas. Samples were analyzed using X-ray diffraction (XRD), thermal analysis, Fourier-transform infrared (FTIR) spectroscopy, and petrographic, scanning (SEM), and transmission (TEM) electron microscopic methods. Sepiolite and palygorskite are blocky and earthy-type materials that display fibrous characteristics when viewed using TEM and SEM and occurred alone or with chalcedony in veins. The fibers of blocky sepiolite are commonly intercalated with smectite but the earthy type of sepiolite and palygorskite observed in this study displayed precipitation from fluid enriched in Si, Al, Mg, and minor Fe and depleted in other ions at an earlier stage of offset of the andesitic veins. Continuation of reverse faulting and high shearing stress caused the precipitation of a significant quantity of interlaminated sepiolite. Sepiolite and palygorskite were formed at an earlier stage of fluid interaction relative to smectite in the Tuluanshan Formation.

Soil aggregates consist of sand, silt, and clay size particles. Many of the clay size particles in soils are clay minerals, which actively influence soil behavior. The properties of clay minerals may change significantly as soil particle size decreases to the nanoscale; however, little information is available about these properties for the Ultisols in China. In the present study, the clay mineral components and structural characteristics of four particle-size fractions (i.e., <2000, 450–2000, 100–450, and 25–100 nm) of two Ultisol samples (Ult-1 and Ult-2) were investigated using elemental analysis, X-ray diffraction, Fouriertransform infrared spectroscopy, and thermal analysis. The molar SiO2 to Al2O3 ratios were lower in the nanoscale particle-size fraction (25–100 nm) than in the 450–2000 and <2000 nm fractions. This indicates greater desilicification and allitization of the smaller Ultisol particles. Furthermore, the Fe oxide and Al oxide contents increased and reached a maximum level in the 25–100 nm fraction of the two Ultisols. Goethite was mainly found in the 100–450 nm and 25–100 nm fractions. The dominant clay minerals in the Ultisol 25–100 nm fraction were kaolinite and illite with a small amount of a hydroxy-interlayered mineral in Ult-1 and gibbsite in Ult-2. The kaolinite crystallinity decreased as particle size decreased. The low crystallinity of the kaolinite in the A horizon 25–100 nm fraction was attributed to a reduction in the thickness of coherent scattering domains, as well as to decreases in OH groups and the dimensions of octahedral AlO6 sheets. A determination of the chemical and mineralogic properties of the different size fractions of the Ultisols is important to understand the desilicification and Al and Fe oxide enrichment mechanisms during soil formation. The significance of these results can help to reveal the nanoscale transformations of clay minerals. Analysis of clay mineral compositions in nanoparticles can provide the additional data needed to understand the adsorption and mobility of nutrients and pollutants.

Layered double hydroxides (LDHs) are known as ‘anionic clays’. They comprise a class of material with positively charged octahedral double hydroxyl layers and exchangeable anions. The Li/Al LDH term includes a group of LDHs with Li/Al octahedral double hydroxyl layers. We have demonstrated a modifed method, using Li/Al LDH-OH (OH− as interlayer anions) as the starting material, for preparing Li/Al LDH-X (X represents interlayer anions, including dioctyl sulphosuccinate (DOSS), dodecyl sulphate (DDS), mercaptoacetate (MA), EDTA, Tiron and dichromate) under mild acid conditions (pH in the range 4 to 5). However, in the case of acidsensitive anions, Fe(CN)64−, Li/Al LDH-Fe(CN)64− can be prepared by a two-step procedure using Li/Al LDH-DOSS or similar compounds as intermediates to react with acid-sensitive anions under mild alkaline conditions (pH ≈ 9).

The Linkuo terrace, situated to the west of the Taipei Basin in NW Taiwan, has thick red soils that have been little studied. This paper aims to interpret the development of these soils through chemical and micromorphological investigations, and relate the soils to their palaeo-environments. The soil samples were air dried, crushed and passed through a 2 mm sieve, and then subjected to conventional soil chemical and physical analyses, together with clay mineralogical and morphological characterization. Pedons I and II were clay with low base saturation (BS), cation-exchange capacity (CEC), and exchangeable cations. The pH of pedons I and II ranged from 3.80 to 5.26. The low magnetic susceptibility of these soils indicates that no magnetite (Fe3O4) or maghemite (γ-Fe2O3) are present. X-ray diffraction patterns of the magnetic clay fraction showed lepidocrocite, goethite and hematite, the amounts of which may relate to water fluctuation in the soil environments. Illite, kaolinite and quartz are major clay minerals in the red soil clay fractions. The micromorphology of all horizons showed a great accumulation of Fe-oxides. The upper horizon showed darkened isotropic Fe-oxide materials, and lower horizon showed a black to reddish dense plasma with soil matrix. The groundmass of the oxic horizon is generally characterized by a homogeneous distribution of the different coarse and fine constituents. The thick (4 m depth) and homogeneous red soils of the Linkuo terrace were developed from fine sediments after the gradual subsidence of the Taipei Basin. Alarge amount of gravel was flushed from the Xindian River before the Taipei Basin subsided. The Linkuo red soils can be classified as mesic, Typic Kandiudox. From the chemical compositions of clay fractions and the red soil features, these red soils can be considered as lateritic red earths or red earths that do not reach the criteria for laterite.

The purpose of the present study was to examine the effects of Toona sinensis Roemor extracts on antioxidative activities, brain morphological changes and cognitive ability. In an in vitro study, the antioxidant capacities of water extracts from Toona sinensis Roemor leaf (TSL), root (TSR) and bark (TSB) were evaluated by an α,α-diphenyl-β-pricryl-hydrazyl radical-scavenging test. The results showed that the scavenging activities of all Toona sinensis Roemor extracts were over 80% at a concentration of 0·625mg/ml. In an in vivo study, 3-month-old male senescence-accelerated-prone 8 mice were used as the tested subjects and fed four different diets: casein diet or casein diet supplemented with 1% TSL, TSR or TSB extract for 12 weeks. The results showed that the mice supplemented with Toona sinensis Roemor extracts demonstrated significantly less amyloid β-protein deposition and lower levels of thiobarbituric acid-reactive substances than the control group. All Toona sinensis Roemor diet groups also showed better active shuttle avoidance responses, and higher superoxide dismutase, catalase and glutathione peroxidase activities, than the control group. It can thus be concluded that supplementation with either TSL, TSR or TSB extract could not only reduce the incidence of ß-amyloid plaques, but also improve learning and memory ability in senescence-accelerated-prone 8 mice. This might be due to the beneficial effects of Toona sinensis Roemor extracts on promoting the antioxidative defence system.

At a medical center in Taiwan, all workers were examined by chest radiography, to determine the prevalence of pulmonary tuberculosis. The prevalence of tuberculosis among all hospital workers was 0.12%, that among nurses was 0.35%, and that among externally contracted cleaners was 0.57%. All of the Mycobacterium tuberculosis isolates recovered from 2 nurses and from a patient with pulmonary tuberculosis were the Beijing strain, but the strains had different serotypes.