Showing papers by "Chinese Academy of Sciences published in 2002"
TL;DR: In this article, a super-hydrophobic surface with both a large contact angle (CA) and a small sliding angle (α) has been constructed from carbon nanotubes.
Abstract: Super-hydrophobic surfaces, with a water contact angle (CA) greater than 150degreesC, have attracted much interest for both fundamental research and practical applications. Recent studies on lotus and rice leaves reveal that a super-hydrophobic surface with both a large CA and small sliding angle (alpha) needs the cooperation of micro- and nanostructure, and the arrangement of the microstructures on this surface can influence the way a water droplet tends to move. These results form the natural world provide a guide for constructing artificial super-hydrophobic surfaces and designing surfaces with controllable wettability. Accordingly, super-hydrophobic surfaces of polymer nanofibers and differently patterned aligned carbon nanotube (ACNT) films have been fabricated.
3,781 citations
TL;DR: This new evidence indicates that large source areas of aeolian dust and energetic winter monsoon winds to transport the material must have existed in the interior of Asia by the early Miocene epoch, at least 14 million years earlier than previously thought.
Abstract: The initial desertification in the Asian interior is thought to be one of the most prominent climate changes in the Northern Hemisphere during the Cenozoic era1,2,3,4. But the dating of this transition is uncertain, partly because desert sediments are usually scattered, discontinuous and difficult to date. Here we report nearly continuous aeolian deposits covering the interval from 22 to 6.2 million years ago, on the basis of palaeomagnetic measurements and fossil evidence. A total of 231 visually definable aeolian layers occur as brownish loesses interbedded with reddish soils. This new evidence indicates that large source areas of aeolian dust and energetic winter monsoon winds to transport the material must have existed in the interior of Asia by the early Miocene epoch, at least 14 million years earlier than previously thought3,5. Regional tectonic changes and ongoing global cooling are probable causes of these changes in aridity and circulation in Asia.
1,501 citations
TL;DR: A framework for landslide risk assessment and management by which landslide risk can be reduced is proposed, and a critical review of the current state of research on assessing the probability of landsliding, runout behavior, and vulnerability is reviewed.
1,135 citations
Council on Education for Public Health1, Cancer Research UK2, French Institute of Health and Medical Research3, Peking Union Medical College4, Chinese Academy of Sciences5, University of Geneva6, National Cancer Research Institute7, Temple University8, University of Los Andes9, Florida International University10, Harbin Medical University11, Yale University12, Stanford University13, University of Turin14, Marshfield Clinic15
TL;DR: A resource of 1064 cultured lymphoblastoid cell lines from individuals in different world populations and corresponding milligram quantities of DNA is deposited at the Foundation Jean Dausset (CEPH) in Paris.
Abstract: A resource of 1064 cultured lymphoblastoid cell lines (LCLs) ([1][1]) from individuals in different world populations and corresponding milligram quantities of DNA is deposited at the Foundation Jean Dausset (CEPH) ([2][2]) in Paris. LCLs were collected from various laboratories by the Human Genome
1,002 citations
TL;DR: In this article, the authors used a Geographical Information Systems (GIS) database, compiled primarily from existing digital maps and aerial photographs, to describe the physical characteristics of landslides and the statistical relations of landslide frequency with the physical parameters contributing to the initiation of landslide on Lantau Island in Hong Kong.
989 citations
TL;DR: A novel watermarking algorithm based on singular value decomposition (SVD) is proposed and results show that the newwatermarking method performs well in both security and robustness.
Abstract: Digital watermarking has been proposed as a solution to the problem of copyright protection of multimedia documents in networked environments. There are two important issues that watermarking algorithms need to address. First, watermarking schemes are required to provide trustworthy evidence for protecting rightful ownership. Second, good watermarking schemes should satisfy the requirement of robustness and resist distortions due to common image manipulations (such as filtering, compression, etc.). In this paper, we propose a novel watermarking algorithm based on singular value decomposition (SVD). Analysis and experimental results show that the new watermarking method performs well in both security and robustness.
978 citations
TL;DR: A grain refinement mechanism induced by plastic deformation during the SMA treatment in Fe was proposed in this article, which involves formation of dense dislocation walls (DDWs) and dislocation tangles (DTs) in original grains and in the refined cells under further straining.
889 citations
TL;DR: Wang et al. as discussed by the authors showed that there is a significant positive linear correlation between the annual food production and annual chemical fertilizer consumption throughout 1949-1998, and the regression coefficient, b, in each period of 10 years since 1949 has been declining rapidly.
Abstract: China is a big country with a huge population and limited farmland area per capita To produce enough food for feeding the population is of vital importance for the county A huge achievement in food production since 1949 has been made The regression analysis in each period of 10 years shows that there is a significant positive linear correlation between the annual food production and annual chemical fertilizer N (CF-N) consumption throughout 1949–1998 However, the regression coefficient, b, in each period of 10 years since 1949 has been declining rapidly Meanwhile, environmental pollution is becoming a serious issue In last 20 years, N concentratjons in surface and ground water have been increasing, `Alga blooms' in lakes and `red tides' in estuaries occur frequently, and the emissions of N2O and NH3 from farmlands rise This paper reviews the causes for the declining N efficiency and rising environmental impacts, and the strategies for better fertilizer management
865 citations
TL;DR: In this paper, geochemical and isotopic data for Early Cretaceous Anjishan adakitic intrusive rocks that are in a continental setting unrelated to subduction were reported.
Abstract: To the best of our knowledge, modern adakites have not been documented in a nonarc environment. We report geochemical and isotopic data for Early Cretaceous Anjishan adakitic intrusive rocks that are in a continental setting unrelated to subduction. The Anjishan adakitic intrusive rocks, which are exposed in the Ningzhen area of east China, have high Sr/Y and La/Yb ratios coupled with low Yb and Y as well as relatively high MgO contents and Mg numbers (Mg#; 0.4-0.6), similar to products from slab melting. However, low ∈ N d ( t ) values (-6.8 to-9.7) and high ( 8 7 Sr/ 8 6 Sr) i (0.7053-0.7066) are inconsistent with an origin by slab melting. The tectonics and geochemistry lead us to conclude that adakitic magmas were most likely derived from partial melting of mafic material at the base of the continental crust. High Sr/Y and La/Yb ratios of the adakitic intrusive rocks suggest that garnet was stable as a residual phase during partial melting, implying that the crustal thickness exceeded 40 km in the Early Cretaceous. The present thickness of the crust in the Ningzhen area is only 30 km, and therefore the crust appears to have been thinned by at least ∼10 km since the Early Cretaceous. The relatively high MgO contents and Mg# of the Anjishan intrusive rocks suggest that adakitic magmas interacted with mantle rocks, possibly coinciding with lower-crustal delamination, which would also account for the observed thinning.
813 citations
TL;DR: A new type of crystalline trititanate nanotube (see Figure and inside front cover for a 3D drawing) has been synthesized in a single alkali treatment.
Abstract: A new type of crystalline trititanate nanotube (see Figure and inside front cover for a 3D drawing) has been synthesized in a single alkali treatment. Novel formation mechanisms of the nanotubes are proposed based on a series of experiments. In the process, NaOH can be regarded as a catalyst and a reusable source. The synthetic method is extremely inexpensive and may be applied to synthesize other oxide nanostructures.
789 citations
TL;DR: The (conditional) minimum average variance estimation (MAVE) method is proposed, which is applicable to a wide range of models, with fewer restrictions on the distribution of the covariates, to the extent that even time series can be included.
Abstract: Summary. Searching for an effective dimension reduction space is an important problem in regression, especially for high dimensional data. We propose an adaptive approach based on semiparametric models, which we call the (conditional) minimum average variance estimation (MAVE) method, within quite a general setting. The MAVE method has the following advantages. Most existing methods must undersmooth the nonparametric link function estimator to achieve a faster rate of consistency for the estimator of the parameters (than for that of the nonparametric function). In contrast, a faster consistency rate can be achieved by the MAVE method even without undersmoothing the nonparametric link function estimator. The MAVE method is applicable to a wide range of models, with fewer restrictions on the distribution of the covariates, to the extent that even time series can be included. Because of the faster rate of consistency for the parameter estimators, it is possible for us to estimate the dimension of the space consistently. The relationship of the MAVE method with other methods is also investigated. In particular, a simple outer product gradient estimator is proposed as an initial estimator. In addition to theoretical results, we demonstrate the efficacy of the MAVE method for high dimensional data sets through simulation. Two real data sets are analysed by using the MAVE approach.
TL;DR: In this article, the authors report SHRIMP (sensitive high-resolution ion microprobe) evidence that suggests a Grenvillian continental collision in south China, including (1) evidence for 1.3-1.0 Ga metamorphism on both sides of the Sibao orogen between the Yangtze and Cathaysia blocks and (2) sedimentary provenance of possible foreland basins that were derived from the cathaysia block and the sibao block during the continental collision.
Abstract: The timing of continental collision between the Yangtze and Cathaysia blocks of south China is an issue that bears on the accretion of Asia, as well as on the assembly and configuration of the Neoproterozoic supercontinent Rodinia. We report in this paper SHRIMP (sensitive high-resolution ion microprobe) evidence that suggests a Grenvillian continental collision in south China, including (1) evidence for 1.3–1.0 Ga metamorphism on both sides of the Sibao orogen between the Yangtze and Cathaysia blocks and (2) sedimentary provenance of possible foreland-basin deposits on the Yangtze side of the orogen that were derived from the Cathaysia block and the Sibao orogen during the continental collision. The occurrence of ca. 1430 Ma granodiorites in southern Cathaysia, along with ca. 1800 Ma basement and Archean protoliths in northern Cathaysia, makes Cathaysia a possible western extension of the Mojave province in southwestern Laurentia. Together with regional data, we suggest that the Sibao orogen could be one of the Grenvillian sutures at the center of Rodinia assembly that brought Australia, Yangtze, and Cathaysia-Laurentia together by ca. 1000 Ma.
TL;DR: In this paper, a detailed investigation of the three main binary evolution channels that can lead to the formation of sdB stars: the common-envelope (CE) ejection channel, the stable Roche lobe overflow (RLOF) channel, and the double helium white dwarfs (WDs) merger channel is presented.
Abstract: Subdwarf B (sdB) stars (and related sdO/sdOB stars) are believed to be helium-core-burning objects with very thin hydrogen-rich envelopes. In recent years it has become increasingly clear from observational surveys that a large fraction of these objects are members of binary systems. To understand their formation better, we present the results of a detailed investigation of the three main binary evolution channels that can lead to the formation of sdB stars: the common-envelope (CE) ejection channel, the stable Roche lobe overflow (RLOF) channel, and the double helium white dwarfs (WDs) merger channel. The CE ejection channel leads to the formation of sdB stars in short-period binaries with typical orbital periods between 0.1 and 10 d, very thin hydrogen-rich envelopes and a mass distribution sharply peaked around similar to0.46 M-.. On the other hand, under the assumption that all mass transferred is soon lost, the stable RLOF channel produces sdB stars with similar masses but long orbital periods (400-1500 d) and with rather thick hydrogen-rich envelopes. The merger channel gives rise to single sdB stars whose hydrogen-rich envelopes are extremely thin but which have a fairly wide distribution of masses (0.4-0.65 M-.). We obtained the conditions for the formation of sdB stars from each of these channels using detailed stellar and binary evolution calculations where we modelled the detailed evolution of sdB stars and carried out simplified binary population synthesis simulations. The observed period distribution of sdB stars in compact binaries strongly constrains the CE ejection parameters. The best fits to the observations are obtained for very efficient CE ejection where the envelope ionization energy is included, consistent with previous results. We also present the distribution of sdB stars in the T (eff) -log g diagram, the Hertzsprung-Russell diagram and the distribution of mass functions.
TL;DR: In this article, the authors show that carbon nanotubes (CTNs) show exceptional adsorption capability and high adorption efficiency for lead removal from water and suggest that CNTs can be good Pb2+ adsorbers and have great potential applications in environmental protection.
TL;DR: The strong associations between anthropogenic Pb and the Fe-Mn oxide and organic/sulphide phases suggested that anthropogenic Cd and Pb was relatively stable after deposition in soils.
TL;DR: In this article, a Pechini sol−gel process combined with soft lithography was used to fabricate nanocrystalline YVO4:A (A = Eu3+, Dy3+, Sm3+, Er3+) phosphor films and their patterning were fabricated by a pechini sol-gel process.
Abstract: Nanocrystalline YVO4:A (A = Eu3+, Dy3+, Sm3+, Er3+) phosphor films and their patterning were fabricated by a Pechini sol−gel process combined with soft lithography. X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), thermogravimetric and differential thermal analysis (TG-DTA), atomic force microscopy (AFM) and optical microscopy, UV/vis transmission and absorption spectra, photoluminescence (PL) spectra, and lifetimes were used to characterize the resulting films. The results of XRD indicated that the films began to crystallize at 400 °C and the crystallinity increased with the increase of annealing temperatures. Transparent nonpatterned phosphor films were uniform and crack-free, which mainly consisted of grains with an average size of 90 nm. Patterned gel and crystalline phosphor film bands with different widths (5−60 μm) were obtained. Significant shrinkage and a few defects were observed in the patterned films during the heat treatment process. The doped rare earth ions (A) show...
TL;DR: A novel method for fabrication of horseradish peroxidase biosensor has been developed by self-assembling gold nanoparticles to a thiol-containing sol-gel network that exhibited high sensitivity, good reproducibility, and long-term stability.
Abstract: A novel method for fabrication of horseradish peroxidase biosensor has been developed by self-assembling gold nanoparticles to a thiol-containing sol−gel network. A cleaned gold electrode was first immersed in a hydrolyzed (3-mercaptopropyl)-trimethoxysilane (MPS) sol−gel solution to assemble three-dimensional silica gel, and then gold nanoparticles were chemisorbed onto the thiol groups of the sol−gel network. Finally, horseradish peroxidase (HRP) was adsorbed onto the surface of the gold nanoparticles. The distribution of gold nanoparticles and HRP was examined by atomic force microscopy (AFM). The immobilized horseradish peroxidase exhibited direct electrochemical behavior toward the reduction of hydrogen peroxide. The performance and factors influencing the performance of the resulting biosensor were studied in detail. The resulting biosensor exhibited fast amperometric response (2.5 s) to H2O2. The detection limit of the biosensor was 2.0 μmol L-1, and the linear range was from 5.0 μmol L-1 to 10.0 m...
TL;DR: In this article, a self-assembly method was used to synthesize polyaniline (PANI) nanostuctures in the presence of inorganic acids (e.g., HCl, H2SO4, HBF4, and H3PO4) as dopants.
Abstract: With an average diameter of 150−340 nm and a conductivity of 10-1−100 S/cm, nanostructures (e.g., nanotubes or nanorods) of polyaniline (PANI) were synthesized by a self-assembly method in the presence of inorganic acids (e.g., HCl, H2SO4, HBF4, and H3PO4) as dopants. It was found that the morphology, size, and electrical properties of the resulting nanostructures depended on the dopant structures and the reaction conditions. In particular, all these PANI nanostuctures showed hydrophilic features, and the contact angles with water were measured to be about 27−40° depending on the dopant. The FTIR spectrum, UV−vis absorption spectrum, XPS, and X-ray diffraction were used to characterize the molecular structures of the nanostructures. It was found that their main chain structure and electric structure were identical to those of the emeraldine salt form of PANI. The micelles formed by anilinium cations act as the template like in the formation of PANI nanostructures.
TL;DR: In this paper, finite-time control problem of a class of controllable systems is considered and explicit formulae are proposed for the finite time stabilization of a chain of power-integrators, and discussions about a generalized class of nonlinear systems are given.
TL;DR: In this paper, the photoluminescence spectrum of the ZnO/AAM assembly system depends on the excitation wavelength in the visible region, which is attributed to different types of oxygen vacancies in the znO nanowires.
TL;DR: Three novel complexes of cadmium(II)-trimesate coordination polymers are obtained from hydrothermal reaction, in which the T-shaped molecular bilayer motif and chicken-wire-like motif are further interlinked in interdigitating or alternating fashion to construct the different coordination architectures.
Abstract: Three novel complexes, Cd3tma2·13H2O (1), Cd3tma2·dabco·2H2O (2), and Cd3Htma3·8H2O (3) (tma = trimesate), of cadmium(II)−trimesate coordination polymers are obtained from hydrothermal reaction. 1 ...
TL;DR: The Mesozoic Fangcheng basalts as discussed by the authorseng et al. showed that these basalts are extremely enriched in LREEs ((La/Yb)N=39.3-49.3) and LILEs (Ce, Rb, Ba, U, Th), with slightly negative Pb anomaly.
Abstract: Major- and trace-element as well as Sr–Nd–Pb isotopic data of the Mesozoic Fangcheng basalts provide an insight into the nature of their mantle source and the secular evolution of the lithospheric mantle beneath the North China Craton. Fangcheng basalts include alkali basalt and olivine tholeiite, both characterized by high Mg (Mg#=65–72), Si, and Ca and low K+Na, Ti, and P. They are extremely enriched in LREEs ((La/Yb)N=39.3–49.3) and LILEs (Ce, Rb, Ba, U, Th) and depleted in HFSEs (Nb, Ta, Zr, Hf, Ti), with slightly negative Pb anomaly. Correspondingly, these basalts are exceedingly high in e
Sr (74.0~81.5) and low in e
Nd (–13.1~–14.2) and 206Pb/204Pb (<17.8). Since crustal contamination during the magma ascent is insignificant, the Fangcheng basalts could reflect the nature of its mantle source. The isotopic data of these basalts cannot be explained by mixing of typical mantle components, but can be accounted for by interaction of an old lithospheric mantle with the lower/middle crust. Therefore, we consider that these basalts originated from the Mesozoic lithospheric mantle, which evolved from its Paleozoic counterpart through extensive interaction with a crust-derived melt. We propose that this melt was generated from the melting of the subducted lower crust of the Yangtze Craton. This peculiar Mesozoic lithospheric mantle somehow was in turn replaced later by the hot and thin Cenozoic lithospheric mantle.
TL;DR: This study investigated how a suite of commonly used landscape metrics respond to changing grain size, extent, and the direction of analysis (or sampling) using several different landscapes in North America to adequately quantify spatial heterogeneity.
Abstract: While ecologists are well aware that spatial heterogeneity is scale-dependent, a general understanding of scaling relationships of spatial pattern is still lacking. One way to improve this understanding is to systematically examine how pattern indices change with scale in real landscapes of different kinds. This study, therefore, was designed to investigate how a suite of commonly used landscape metrics respond to changing grain size, extent, and the direction of analysis (or sampling) using several different landscapes in North America. Our results showed that the responses of the 19 landscape metrics fell into three general categories: Type I metrics showed predictable responses with changing scale, and their scaling relations could be represented by simple scaling equations (linear, power-law, or logarithmic functions); Type II metrics exhibited staircase-like responses that were less predictable; and Type III metrics behaved erratically in response to changing scale, suggesting no consistent scaling relations. In general, the effect of changing grain size was more predictable than that of changing extent. Type I metrics represent those landscape features that can be readily and accurately extrapolated or interpolated across spatial scales, whereas Type II and III metrics represent those that require more explicit consideration of idiosyncratic details for successful scaling. To adequately quantify spatial heterogeneity, the metric-scalograms (the response curves of metrics to changing scale), instead of single-scale measures, seem necessary.
TL;DR: A genetic analysis of grain-size components of hydraulic and aeolian sediments demonstrates the following environmental implications: Fluvial sediment is composed of isolated saltation and suspension components as discussed by the authors.
TL;DR: The expansion of this cost-saving technology is increasing the supply of cotton and pushing down the price, but prices are still sufficiently high for adopters of Bt cotton to make substantial gains in net income.
Abstract: Bt cotton is spreading very rapidly in China, in response to demand from farmers for technology that will reduce both the cost of pesticide applications and exposure to pesticides, and will free up time for other tasks. Based on surveys of hundreds of farmers in the Yellow River cotton-growing region in northern China in 1999, 2000 and 2001, over 4 million smallholders have been able to increase yield per hectare, and reduce pesticide costs, time spent spraying dangerous pesticides, and illnesses due to pesticide poisoning. The expansion of this cost-saving technology is increasing the supply of cotton and pushing down the price, but prices are still sufficiently high for adopters of Bt cotton to make substantial gains in net income.
TL;DR: CDNA array on genes mainly made from the cDNA libraries of lumbar DRGs of normal rats and of rats 14 days after peripheral axotomy reveals dynamic and complex changes in molecular diversity among DRG neurons after axotomy.
Abstract: Phenotypic modification of dorsal root ganglion (DRG) neurons represents an important mechanism underlying neuropathic pain. However, the nerve injury-induced molecular changes are not fully identified. To determine the molecular alterations in a broader way, we have carried out cDNA array on the genes mainly made from the cDNA libraries of lumbar DRGs of normal rats and of rats 14 days after peripheral axotomy. Of the 7,523 examined genes and expressed sequence tags (ESTs), the expression of 122 genes and 51 expressed sequence tags is strongly changed. These genes encompass a large number of members of distinct families, including neuropeptides, receptors, ion channels, signal transduction molecules, synaptic vesicle proteins, and others. Of particular interest is the up-regulation of gamma-aminobutyric acidA receptor alpha5 subunit, peripheral benzodiazepine receptor, nicotinic acetylcholine receptor alpha7 subunit, P2Y1 purinoceptor, Na+ channel beta2 subunit, and L-type Ca2+ channel alpha2delta-1 subunit. Our findings therefore reveal dynamic and complex changes in molecular diversity among DRG neurons after axotomy.
TL;DR: A convenient route at ambient conditions was employed to prepare narrow-dispersed ZnO nanorods in terms of size and morphology and transmission electron microscopy and X-ray diffraction were used to characterize the structurally uniform and well-proportioned products.
Abstract: A convenient route at ambient conditions was employed to prepare narrow-dispersed ZnO nanorods in terms of size and morphology. Transmission electron microscopy and X-ray diffraction were used to characterize the structurally uniform and well-proportioned products. The as-prepared specimen exhibits strong ultraviolet exciton emission at 385 nm and disappearance of visible defect emission.
TL;DR: The results of a multiple, isotopic, chemical and mineralogical analysis of loess from the three northwestern inland basins (the Junggar Basin, the Tarim Basin and the Qaidam Basin) and the Loess Plateau region of China are summarized in this paper.