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Showing papers by "Chinese Academy of Sciences published in 2001"


Journal ArticleDOI
Eric S. Lander1, Lauren Linton1, Bruce W. Birren1, Chad Nusbaum1  +245 moreInstitutions (29)
15 Feb 2001-Nature
TL;DR: The results of an international collaboration to produce and make freely available a draft sequence of the human genome are reported and an initial analysis is presented, describing some of the insights that can be gleaned from the sequence.
Abstract: The human genome holds an extraordinary trove of information about human development, physiology, medicine and evolution. Here we report the results of an international collaboration to produce and make freely available a draft sequence of the human genome. We also present an initial analysis of the data, describing some of the insights that can be gleaned from the sequence.

22,269 citations


Journal ArticleDOI
TL;DR: Aggregation greatly boosts emission efficiency of the silole, turning it from a weak luminophor into a strong emitter.

5,916 citations


Journal ArticleDOI
TL;DR: In this article, the authors track some of the major myths on driving forces of land cover change and propose alternative pathways of change that are better supported by case study evidence, concluding that neither population nor poverty alone constitute the sole and major underlying causes of land-cover change worldwide.
Abstract: Common understanding of the causes of land-use and land-cover change is dominated by simplifications which, in turn, underlie many environment-development policies. This article tracks some of the major myths on driving forces of land-cover change and proposes alternative pathways of change that are better supported by case study evidence. Cases reviewed support the conclusion that neither population nor poverty alone constitute the sole and major underlying causes of land-cover change worldwide. Rather, peoples’ responses to economic opportunities, as mediated by institutional factors, drive land-cover changes. Opportunities and

3,330 citations


Journal ArticleDOI
14 Dec 2001-Science
TL;DR: The record links North Atlantic climate with the meridional transport of heat and moisture from the warmest part of the ocean where the summer East Asian Monsoon originates and generally agrees with the timing of temperature changes from the Greenland Ice Sheet Project Two (GISP2).
Abstract: Oxygen isotope records of five stalagmites from Hulu Cave near Nanjing bear a remarkable resemblance to oxygen isotope records from Greenland ice cores, suggesting that East Asian Monsoon intensity changed in concert with Greenland temperature between 11,000 and 75,000 years before the present (yr. B.P.). Between 11,000 and 30,000 yr. B.P., the timing of changes in the monsoon, as established with 230Th dates, generally agrees with the timing of temperature changes from the Greenland Ice Sheet Project Two (GISP2) core, which supports GISP2's chronology in this interval. Our record links North Atlantic climate with the meridional transport of heat and moisture from the warmest part of the ocean where the summer East Asian Monsoon originates.

2,759 citations


Journal ArticleDOI
03 May 2001-Nature
TL;DR: The results of a numerical climate-model experiment support the argument that the stages in evolution of Asian monsoons are linked to phases of Himalaya–Tibetan plateau uplift and to Northern Hemisphere glaciation.
Abstract: The climates of Asia are affected significantly by the extent and height of the Himalayan mountains and the Tibetan plateau1,2,3,4 Uplift of this region began about 50 Myr ago, and further significant increases in altitude of the Tibetan plateau are thought to have occurred about 10–8 Myr ago4,5, or more recently However, the climatic consequences of this uplift remain unclear Here we use records of aeolian sediments from China6,7 and marine sediments from the Indian8,9,10 and North Pacific oceans11 to identify three stages of evolution of Asian climates: first, enhanced aridity in the Asian interior and onset of the Indian and east Asian monsoons, about 9–8 Myr ago; next, continued intensification of the east Asian summer and winter monsoons, together with increased dust transport to the North Pacific Ocean11, about 36–26 Myr ago; and last, increased variability and possible weakening of the Indian and east Asian summer monsoons and continued strengthening of the east Asian winter monsoon since about 26 Myr ago The results of a numerical climate-model experiment, using idealized stepwise increases of mountain–plateau elevation, support the argument that the stages in evolution of Asian monsoons are linked to phases of Himalaya–Tibetan plateau uplift and to Northern Hemisphere glaciation

2,329 citations


Journal ArticleDOI
TL;DR: Methods for avoiding Numts have now been tested, and several recent studies demonstrate the potential utility of Numt DNA sequences in evolutionary studies.
Abstract: Nuclear copies of mitochondrial DNA (mtDNA) have contaminated PCR-based mitochondrial studies of over 64 different animal species. Since the last review of these nuclear mitochondrial pseudogenes (Numts) in animals, Numts have been found in 53 of the species studied. The recent evidence suggests that Numts are not equally abundant in all species, for example they are more common in plants than in animals, and also more numerous in humans than in Drosophila. Methods for avoiding Numts have now been tested, and several recent studies demonstrate the potential utility of Numt DNA sequences in evolutionary studies. As relics of ancient mtDNA, these pseudogenes can be used to infer ancestral states or root mitochondrial phylogenies. Where they are numerous and selectively unconstrained, Numts are ideal for the study of spontaneous mutation in nuclear genomes.

1,055 citations


Journal ArticleDOI
TL;DR: Alkylimidazolium tetrafluoroborates are promising versatile lubricants for the contact of steel/steel, steel/aluminium, steel/(100), steel/copper, steel’sialon ceramics, Si3N4/SiO2 and steel/Si(100) show excellent friction reduction, antiwear performance and high load-carrying capacity.

922 citations


Journal ArticleDOI
TL;DR: In this paper, the authors provide a conceptual framework to guide efforts toward improved estimates of forest net primary production (NPP) in the world's forests, and assess the implications of the limitations of past studies for current understanding of NPP in forest ecosystems, discuss how field NPP* measurements can be used to complement tower-based studies of forest carbon flux, and recommend design criteria for future field studies of Forest NPP.
Abstract: There are pressing reasons for developing a better understanding of net primary production (NPP) in the world's forests. These ecosystems play a large role in the world's carbon budget, and their dynamics, which are likely to be responding to global changes in climate and atmospheric composition, have major economic implications and impacts on global biodiversity. Although there is a long history of forest NPP studies in the ecological literature, current understanding of ecosystem-level production remains lim- ited. Forest NPP cannot be directly measured; it must be approached by indirect methods. To date, field measurements have been largely restricted to a few aspects of NPP; methods are still lacking for field assessment of others, and past studies have involved confusion about the types of measurements needed. As a result, existing field-based estimates of forest NPP are likely to be significant underestimates. In this paper we provide a conceptual framework to guide efforts toward improved estimates of forest NPP. We define the quantity NPP* as the summed classes of organic material that should be measured or estimated in field studies for an estimate of total NPP. We discuss the above- and belowground components of NPP* and the available methods for measuring them in the field. We then assess the implications of the limitations of past studies for current understanding of NPP in forest ecosystems, discuss how field NPP* measurements can be used to complement tower-based studies of forest carbon flux, and recommend design criteria for future field studies of forest NPP.

902 citations


Journal ArticleDOI
TL;DR: This study illuminates the unusual phenomena and shows how understanding of the central problem to generate a 1,3-dipole from alkynoates or allenoates by interaction with various phosphines allows control of the reaction.
Abstract: The development of some new synthetic reactions derived from nucleophilic addition of phosphines to electron-deficient carbon-carbon triple bonds is described. These reactions show that the phosphine plays the role of a nucleophile as well as an excellent leaving group. The central problem is to generate a 1,3-dipole from alkynoates or allenoates (2,3-butadienoates) by interaction with various phosphines. This study illuminates the unusual phenomena and shows how this understanding allows control of the reaction.

865 citations


Journal ArticleDOI
TL;DR: Sino-Korean Craton (SKC) is an important natural laboratory for studying temporal change to the lithosphere because there is the jutaxposition of Ordovician diamondiferous kimberlites, Mesozoic lamprophyre-basalt and Cenozoic tholeiite-alkali basalts in this craton.
Abstract: Sino-Korean Craton (SKC) in eastern China is an important natural laboratory for studying temporal change to the lithosphere because there is the jutaxposition of Ordovician diamondiferous kimberlites, Mesozoic lamprophyre-basalt and Cenozoic tholeiite-alkali basalts in this craton. While diamond inclusions, xenoliths and mineral concentrates in kimberlites indicate a thick (180 km), cold and refractory lithospheric keel beneath the SKC prior to the Palaeozoic, basalt-borne xenoliths reveal the presence of thin (

779 citations


Journal ArticleDOI
01 Sep 2001-Lithos
TL;DR: Based on petrographic, major and trace element, and Sr-Nd isotope data, the Emeishan basalts can be classified into two major magma types: (1) a low-Ti (LT) type that exhibits low Ti/Y ( 500), and (2) HT2 lavas are compositionally similar to the HT1 lavas but show conspicuous depletion in U and Th as discussed by the authors.

Journal ArticleDOI
06 Apr 2001-Science
TL;DR: It is generally perceived that biodiversity is better protected from human activities after an area is designated as a protected area, but it is found that this common perception was not true in Wolong Nature Reserve, which was established in 1975 as a “flagship” protected area for the world-renowned endangered giant pandas.
Abstract: It is generally perceived that biodiversity is better protected from human activities after an area is designated as a protected area. However, we found that this common perception was not true in Wolong Nature Reserve (southwestern China), which was established in 1975 as a “flagship” protected area for the world-renowned endangered giant pandas. Analyses of remote sensing data from pre- and post-establishment periods indicate that the reserve has become more fragmented and less suitable for giant panda habitation. The rate of loss of high-quality habitat after the reserve9s establishment was much higher than before the reserve was created, and the fragmentation of high-quality habitat became far more severe. After the creation of the reserve, rates of habitat loss and fragmentation inside the reserve unexpectedly increased to levels that were similar to or higher than those outside the reserve, in contrast to the situation before the reserve was created.

Journal ArticleDOI
01 Nov 2001-Carbon
TL;DR: Hard carbon with perfect spherical morphology was prepared for the first time by a hydrothermal method as discussed by the authors, which has controllable monodispersed particle size and a smooth surface.

Journal ArticleDOI
TL;DR: In this article, the authors synthesize the data in the primary literature on NPP in old-growth tropical forests to produce a consistent data set on net primary production for these forests.
Abstract: Information on net primary production in tropical forests is needed for the development of realistic global carbon budgets, for projecting how these ecosystems will be affected by climatic and atmospheric changes, and for evaluating eddy covariance mea- surements of tropical forest carbon flux. However, a review of the database commonly used to address these issues shows that it has serious flaws. In this paper we synthesize the data in the primary literature on NPP in old-growth tropical forests to produce a consistent data set on NPP for these forests. Studies in this biome have addressed only a few NPP com- ponents, all aboveground. Given the limited scope of the direct field measurements, we sought relationships in the existing data that allow estimation of unmeasured aspects of production from those that are more easily assessed. We found a predictive relationship between annual litterfall and aboveground biomass increment. For 39 diverse tropical forest sites, we then developed consistent, documented estimates of the upper and lower bounds around total NPP to serve as benchmarks for calibrating and validating biogeochemical models with respect to this biome. We developed these estimates based on existing field measurements, current understanding of aboveground consumption and biogenic volatile organic carbon emissions, and our judgment that belowground production is bounded by the range 0.2-1.2 3 ANPP (aboveground NPP). Across this broad spectrum of tropical forests (dry to wet, lowland to montane, nutrient-rich to nutrient-poor soils), our estimates of lower and upper bounds on total NPP range from 1.7 to 11.8 Mg C·ha 21 ·yr 21 (lower bounds) and from 3.1 to 21.7 Mg C·ha 21 ·yr 21 (upper bounds). We also showed that two relationships that have been used for estimating NPP (the Bray-Gorham relationship based on leaf litterfall and the Miami model based on temperature or precipitation) are not valid for the tropical forest biome.

Journal ArticleDOI
TL;DR: In this paper, the photoluminescence (PL) measurements of TiO2 nanowire arrays show a visible broadband with three peaks at about 425, 465, and 525 nm that are attributed to self-trapped excitons, F, and F+ centers, respectively.
Abstract: Highly ordered TiO2 nanowire (TN) arrays were prepared in anodic alumina membranes (AAMs) by a sol-gel method. The TNs are single crystalline anatase phase with uniform diameters around 60 nm. At room temperature, photoluminescence (PL) measurements of the TN arrays show a visible broadband with three peaks, which are located at about 425, 465, and 525 nm that are attributed to self-trapped excitons, F, and F+ centers, respectively. A model is also presented to explain the PL intensity drop-down of the TN arrays embedded in AAMs: the blue PL band of AAMs arises from the F+ centers on the pore walls, and the TNs first form in the center area of the pores and then extend to the pore walls.

Journal ArticleDOI
01 Dec 2001-Polymer
TL;DR: In this article, a polypropylene (PP)/clay nanocomposites (PPCN) were prepared via grafting-melt compounding by using a new kind of co-intercalation organophilic clay which had a larger interlayer spacing than the ordinarily organophilous clay only modified by alkyl ammonium.

Journal ArticleDOI
TL;DR: A stepwise logistic regression model was obtained between landslide susceptibility and the above mentioned physical parameters as mentioned in this paper, and the study area has been classified into five classes of relative landslide susceptibility, namely, very low, low, moderate, high, and very high.
Abstract: Steep terrain and the high frequency of tropical rainstorms make landslide occurrence on natural terrain a common phenomenon in Hong Kong. For example, more than 800 slope failures were triggered by a rainstorm in November 1993 on Lantau Island, Hong Kong. Maps of recent landslides interpreted from aerial photographs, in combination with a geographical information system, were used to evaluate the frequency and distribution of landslides, with particular reference to such physical parameters as lithology, slope gradient, slope aspect, elevation, vegetation cover, and proximity to drainage line, all of which are considered to be influential in the occurrence of landslides. A stepwise logistic regression model was obtained between landslide susceptibility and the above mentioned physical parameters. The study area has been classified into five classes of relative landslide susceptibility, namely, very low, low, moderate, high, and very high, based on this methodology.

Journal ArticleDOI
TL;DR: In this article, 1.2,3,4,5-Tetraphenylsiloles with different 1,1-substituents on the ring silicon atoms are synthesized and characterized.
Abstract: 2,3,4,5-Tetraphenylsiloles with different 1,1-substituents on the ring silicon atoms, i.e., 1,1-dimethyl-2,3,4,5-tetraphenylsilole (1), 1-methyl-1-(3-chloropropyl)-2,3,4,5-tetraphenylsilole (2), 1-methyl-1,2,3,4,5-pentaphenylsilole (3) and hexaphenylsilole (4), are synthesized and characterized. While all the siloles emit intense blue light readily observable by naked eyes under normal room illumination conditions, the film of their acyclic cousin without silicon, namely 1,2,3,4-tetraphenylbutadiene (5), does not fluoresce, revealing the vital role of the planar and rigid silacyclopentadiene ring in the solid-state photoluminescence process. The electronic transitions of the siloles can be tuned by varying the 1,1-substituents, and the inductive and conjugating effects of the aromatic rings confer low LUMO energy levels and high emission efficiencies on the phenyl-substituted siloles. The electroluminescence device of the 1-phenylsilole 3 shows a high brightness (4538 cd m−2 at 18 V) and an excellent external quantum efficiency (0.65% at 17 V and 94 mA cm−2).

Journal ArticleDOI
TL;DR: PEGylated poly(lactic-co-glycolic acid) (PEG-PLGA) nanoparticles could be an effective carrier for PPD delivery and obviously change the protein biodistribution in rats compared with that of PLGA nanoparticles.

Journal ArticleDOI
TL;DR: In this article, aqueous TiO2 dispersions under UV illumination was examined to assess the influence of temperature, pH, concentration of dissolved oxygen (DOC), initial concentration of MB, and light intensity on the kinetics of decomposition.
Abstract: Methylene blue (MB) is a representative of a class of dyestuffs resistant to biodegradation Its decomposition was examined in aqueous TiO2 dispersions under UV illumination to assess the influence of temperature, pH, concentration of dissolved oxygen (DOC), initial concentration of MB, and light intensity on the kinetics of decomposition Hypsochromic effects (ie blue shifts of spectral bands) resulting from N-demethylation of the dimethylamino group in MB occurs concomitantly with oxidative degradation The maximum quantity of MB adsorbed on TiO2, and the kinetics of degradation of MB and of total organic carbon (TOC) removal were also measured at constant pH 4 Photobleaching of MB solutions takes place at low DOCs and is caused by a reversible reductive process involving photogenerated electrons on TiO2 The rate of degradation of MB remains fairly constant regardless of whether the dispersion was purged with oxygen prior to irradiation or with air during the light irradiation period The photocatalytic process depends on light intensity, but not on the total light energy absorbed The photoreaction followed pseudo-first-order kinetics even at high MB concentrations (03 mM) The temperature dependence of the photodegradation kinetics was assessed (E a =89 kJ/mol ) , as well as the relative photonic efficiency, ξr, relative to phenol (048)

Journal ArticleDOI
TL;DR: The transition of the global atmospheric circulation in the end of 1970's can clearly be detected in the atmospheric temperature, wind velocity, and so on as mentioned in this paper, and wavelet analysis reveals that the temporal scale of this change is larger than 20 years.
Abstract: The transition of the global atmospheric circulation in the end of 1970's can clearly be detected in the atmospheric temperature, wind velocity, and so on. Wavelet analysis reveals that the temporal scale of this change is larger than 20 years. Studies in this work indicate that the trend of the transition over the mid-latitude Asia is opposite to that of global average for some variables at the middle troposphere. Another finding of this research is that the African-Asian monsoon circulation is weaker and the trade wind over the tropical eastern Pacific is weaker as well after this transition. Such a signal may be found in the summer precipitation over China as well.

Journal ArticleDOI
01 Aug 2001-Carbon
TL;DR: In this paper, theoretical predictions and experimental results on the hydrogen uptake of carbon nanotubes and nanofibers are summarized, and they point out that, in order to accelerate the development of carbon Nanotubes as a practical hydrogen storage medium in fuel cell-driven vehicles, many efforts have to be made to reproduce and verify the results both theoretically and experimentally, and to investigate their volumetric capacity, cycling characteristics and release behavior.

Journal ArticleDOI
TL;DR: In this article, a pot experiment was carried out with lettuce (Lactuca sativa) cultivated with increasing amounts of H2SeO4, and the yields harvested 7 or 14 weeks after sowing revealed that a low Se dosage (0.1 mg kg−1 soil) stimulated the growth of senescing seedlings (dry weight yield by 14%) despite a decreased chlorophyll concentration.
Abstract: In human and animal cells, Se plays an essential role in antioxidation and exerts an antiaging function but it is toxic at high dietary intake. To increase its intake in forage and foodstuffs, Se fertilization is adopted in some countries where soils are low in bioavailable Se, even though higher plants are regarded not to require Se. To test its ability to counteract senescence-related oxidative stress in higher plants, a pot experiment was carried out with lettuce (Lactuca sativa) cultivated with increasing amounts of H2SeO4. The yields harvested 7 or 14 weeks after sowing revealed that a low Se dosage (0.1 mg kg−1 soil) stimulated the growth of senescing seedlings (dry weight yield by 14%) despite a decreased chlorophyll concentration. The growth-promoting function was related to diminished lipid peroxidation. In young and senescing plants, the antioxidative effect of Se was associated with the increased activity of glutathione peroxidase (GSH-Px). In the senescing plants, the added Se strengthened the antioxidative capacity also by preventing the reduction of tocopherol concentration and by enhancing superoxide dismutase (SOD) activity. When no Se was added, tocopherols and SOD activity diminished during plant senescence. The higher Se dosage (1.0 mg kg−1 soil) was toxic and reduced the yield of young plants. In the senescing plants, it diminished the dry weight yield but not the fresh weight yield.

Journal ArticleDOI
TL;DR: The XPS survey spectra of ACNT film was shown in Figure 1 before treatment as discussed by the authors, showing that the film mainly consists of carbon accompanied by traces of nitrogen, oxygen and iron.
Abstract: 1 XPS survey spectra of ACNT film was shown in Figure 1 before treatment. XPS results show that the ACNT film mainly consists of carbon accompanied by traces of nitrogen, oxygen and iron. Nitrogen and iron are generated during metal phthalocyanines decomposition (S. M. Huang, L. M. Dai, A. W. H. Mau, J. Phys. Chem. B 1999, 103, 4223.), while oxygen is considered to probably originate from the top-end of CNTs oxidized by air. (H. Ago, T. Kugler, F. Cacialli, W. R. Salaneck, M. S. P. Shaffer, A. H. Windle, R. H. Friend, J. Phys. Chem. B 1999, 103, 8116.)

Journal ArticleDOI
TL;DR: Nano‐Se has a similar bioavailability in the rat and antioxidant effects on cells and is demonstrated to show less pro‐oxidative effects than selenite, as measured by cell growth.
Abstract: A novel selenium form, nano red elemental selenium (Nano-Se) was prepared by adding bovine serum albumin to the redox system of selenite and glutathione. Nano-Se has a 7-fold lower acute toxicity than sodium selenite in mice (LD50 113 and 15 mg Se/kg body weight respectively). In Se-deficient rat, both Nano-Se and selenite can increase tissue selenium and GPx activity. The biological activities of Nano-Se and selenite were compared in terms of cell proliferation, enzyme induction and protection against free racial-mediated damage in human hepatoma HepG2 cells. Nano-Se and selenite are similarly cell growth inhibited and stimulated synthesis of glutathione peroxidase (GPx), phospholipid hydroperoxide glutathione peroxidase (PHGPx) and thioredoxin reductase (TR). When HepG2 cells were co-treated with selenium and glutathione, Nano-Se showed less pro-oxidative effects than selenite, as measured by cell growth. These results demonstrate that Nano-Se has a similar bioavailability in the rat and antioxidant effects on cells.

Journal ArticleDOI
TL;DR: In this article, three commonly used digestion procedures, hotplate aqua regia, microwave aqua and HF, were compared for digestion of three standard reference materials (SRMs 2704, 2709, and 2711) and 20 Florida soils (three groups of Quartzipsammemts, one group of Alaquods, and one groups of Paleudults).
Abstract: It is important to evaluate different digestion methods to accurately determine elemental concentrations in soils. Three commonly used digestion procedures, hotplate aqua regia, microwave aqua regia, and microwave aqua regia + HF, were compared for digestion of three standard reference materials (SRMs 2704, 2709, and 2711) and 20 Florida soils (three groups of Quartzipsammemts, one group of Alaquods, and one group of Paleudults). Sixteen elements (Al, Ba, Ca, Fe, K, Mg, Mn, P, Zn, As, Cd, Cr, Cu, Ni, Pb, and Se) were analyzed using either an inductively coupled plasma optical emission spectrometer (ICP-OES) or a graphite furnace atomic absorption spectrophotometer (GFAAS). Precise analysis was achieved for all elements except As (1.0-25%), Cd (1.8-22%), and Se (4.1-22%) in the SRMs using all three procedures, with the microwave aqua regia + HF procedure having slightly better precision (3.7%) averaged across all elements. Compared with the elemental recoveries in SRMs by the microwave aqua regia digestion (80%), microwave aqua regia + HF digestion achieved greater accuracy (94%), whereas the hotplate aqua regia digestion achieved less accuracy (74%). In general, the microwave aqua regia + HF digestion was overall the best procedure for determining concentrations of most metals in SRMs and Florida soils, followed by the microwave aqua regia and the hotplate aqua regia digestion. However, this so-called total-total digestion procedure (microwave aqua regia + HF) may underestimate total Pb concentration in Florida soils and total Al, Ca, Fe, Mg, and Ba concentrations in the Florida Paleudults.

Journal ArticleDOI
TL;DR: In this paper, a GIS-aid to the geo-environmental evaluation for urban land-use planning is illustrated for the urban area of Lanzhou City and its vicinity in Northwest China.

Journal ArticleDOI
TL;DR: In this paper, the cycloaddition of carbon dioxide to propylene oxide without any additional organic solvents has been investigated, and it was found that 1n-butyl-3-methylimidazolium tetrafluoroborate was the most active catalyst with almost 100% selectivity, and a suitable CO2-propylene oxide molar ratio was needed for high conversion.
Abstract: In room temperature ionic liquids based on 1-n-butyl-3-methylimidazolium and n-butylpyridinium salts, cycloaddition of carbon dioxide to propylene oxide without any additional organic solvents has been investigated. It was found that 1-n-butyl-3-methylimidazolium tetrafluoroborate was the most active catalyst with almost 100% selectivity, and a suitable CO2–propylene oxide molar ratio was needed for high conversion. The ionic liquid used as catalyst for the reaction was recyclable.

Journal ArticleDOI
TL;DR: In this article, Wang et al. showed that persistent groundwater overexploitation in the northern parts of the North China Plain (NCP) has resulted in water-level declines in both shallow and deep aquifers.
Abstract: The North China Plain (NCP) is one of China's most important social, economic, and agricultural regions. Currently, the Plain has 17,950 thousand ha of cultivated land, 71.1 percent of which is irrigated, consuming more than 70 percent of the total water supply. Increasing water demands associated with rapid urban and industrial development and expansion of irrigated land have led to overexploitation of both surface and the ratio of groundwater resources, particularly north of the Yellow River. In 1993, the ratio of groundwater exploitation to recharge in many parts of the NCP exceeded 1.0; in some areas, the ratio exceeded 1.5. Consequently, about 1.06 million ha of water-short irrigated areas in the NCP also have poor water quality. Persistent groundwater overexploitation in the northern parts of the NCP has resulted in water-level declines in both shallow and deep aquifers. According to data from 600 shallow groundwater observation wells in the Hebei Plain, the average depth to water increased...

Journal ArticleDOI
TL;DR: In this paper, the effects of chitosan coating in extending postharvest life of longan fruits and maintaining their quality were investigated, where the fruits were treated with aqueous solutions of 0.5, 1.0 and 2.0% chitosa, respectively, and then stored at 2°C and 90% relative humidity.