Showing papers by "Wuhan University published in 1999"
TL;DR: In this article, a class of π;-conjugated compounds that exhibit large δ (as high as 1, 250 × 10−50 cm4 s per photon) and enhanced two-photon sensitivity relative to ultraviolet initiators were developed and used to demonstrate a scheme for three-dimensional data storage which permits fluorescent and refractive readout, and the fabrication of threedimensional micro-optical and micromechanical structures, including photonic bandgap-type structures.
Abstract: Two-photon excitation provides a means of activating chemical or physical processes with high spatial resolution in three dimensions and has made possible the development of three-dimensional fluorescence imaging1, optical data storage2,3 and lithographic microfabrication4,5,6. These applications take advantage of the fact that the two-photon absorption probability depends quadratically on intensity, so under tight-focusing conditions, the absorption is confined at the focus to a volume of order λ3 (where λ is the laser wavelength). Any subsequent process, such as fluorescence or a photoinduced chemical reaction, is also localized in this small volume. Although three-dimensional data storage and microfabrication have been illustrated using two-photon-initiated polymerization of resins incorporating conventional ultraviolet-absorbing initiators, such photopolymer systems exhibit low photosensitivity as the initiators have small two-photon absorption cross-sections (δ). Consequently, this approach requires high laser power, and its widespread use remains impractical. Here we report on a class of π;-conjugated compounds that exhibit large δ (as high as 1, 250 × 10−50 cm4 s per photon) and enhanced two-photon sensitivity relative to ultraviolet initiators. Two-photon excitable resins based on these new initiators have been developed and used to demonstrate a scheme for three-dimensional data storage which permits fluorescent and refractive read-out, and the fabrication of three-dimensional micro-optical and micromechanical structures, including photonic-bandgap-type structures7.
1,975 citations
TL;DR: In this article, a simple model of endogenous growth with spending by different levels of government is presented, and the authors demonstrate how fiscal decentralization affects the long-run growth rate of the economy, finding that the existing spending shares for state and local governments have been consistent with growth maximization.
441 citations
TL;DR: The first synthesis of a series of dendritic polymers with a core of 1,4,7,10-tetraazacyclodododecane seems to be a promising carrier for the controlled release of antitumor drugs.
170 citations
TL;DR: In this paper, a two-parameter water balance model was developed to simulate the runoff of seventy subcatchments in the Dongjiang, Ganjiang and Hanjiang basins in the south of China.
136 citations
TL;DR: In this article, the relationship between structure and nonlinear optical properties of coordination compounds in terms of influence of molecular configuration on linear and NLO properties is reviewed and empirical rules of these relationships have been proposed, which may help the design of new NLO materials from organometallic and coordination compounds.
100 citations
TL;DR: In this article, a new poly(N-isopropylacrylamide) (PNIPA) hydrogel was prepared by decreasing the temperature of polymerization/crosslinking reaction below the freezing point (-18 °C).
Abstract: A new poly(N-isopropylacrylamide) (PNIPA) hydrogel was prepared by decreasing the temperature of polymerization/crosslinking reaction below the freezing point (-18 °C). This PNIPA hydrogel shows a large swelling ratio at room temperature and exhibits a fast deswelling and reswelling rate in response to external temperature changes. These properties are attributed to the macroporous and regularly arranged network of this PNIPA hydrogel.
95 citations
TL;DR: Results obtained by both X-ray photoelectron spectrometry and cyclic voltammetry show that the largest covalent immobilization amount of dsDNA could be gained on hydroxyl-terminated SAM/Au.
86 citations
TL;DR: The convergence rates of genetic algorithms are discussed by using the minorization condition in the Markov chain theory to obtain the bound on its convergence rate on the general state space and on the finite state space.
85 citations
TL;DR: The discovery of Slp49 contributes to the identification of important functional motifs conserved in p35-like apoptotic suppressors and to the future isolation of p 35-like genes from other baculoviruses.
Abstract: Spodoptera frugiperda SF9 cells infected with mutants of the Autographa californica nucleopolyhedrovirus (AcMNPV) which lack a functional p35 gene undergo apoptosis, aborting the viral infection. The Spodoptera littoralis nucleopolyhedrovirus (SlNPV) was able to suppress apoptosis triggered by vΔP35K/pol+, an AcMNPV p35 null mutant. To identify the putative apoptotic suppressor gene of SlNPV, overlapping cosmid clones representing the entire SlNPV genome were individually cotransfected along with genomic DNA of vΔP35K/pol+. Using this complementation assay, we isolated a SlNPV DNA fragment that was able to rescue the vΔP35K/pol+ infection in SF9 cells. By further subcloning and rescue, we identified a novel SlNPV gene, Slp49. The Slp49 sequence predicted a 49-kDa polypeptide with about 48.8% identity to the AcMNPV apoptotic suppressor P35. SLP49 displays a potential recognition site, TVTDG, for cleavage by death caspases. Recombinant AcMNPVs deficient in p35 bearing the Slp49 gene did not induce apoptosis and showed successful productive infections in SF9 cells, indicating that Slp49 is a functional homologue of p35. A 1.5-kbp Slp49-specific transcript was identified in SF9 cells infected with SlNPV or with vAc496, a vΔP35K/pol+-recombinant bearing Slp49. The discovery of Slp49 contributes to the identification of important functional motifs conserved in p35-like apoptotic suppressors and to the future isolation of p35-like genes from other baculoviruses.
83 citations
TL;DR: The relationship between the luminescence properties and crystal structures, and the energy transfer mechanism are discussed in this article, where the excitation and emission spectra of Tb3+-doped zinc salicylate and Zn(HOC6H4CO2)2:Tb are investigated.
Abstract: The Tb3+-doped zinc salicylate, Zn(HOC6H4CO2)2:Tb, and the zinc monosalicylate, α- and β-Zn(OC6H4CO2): Tb, are synthesized by rheological phase reaction and thermal decomposition. α-Zn(OC6H4CO2): Tb has very strong green emission of Tb3+ under excitation with UV light. The excitation and emission spectra are investigated. The relationship between the luminescence properties and crystal structures, and the energy transfer mechanism are discussed.
81 citations
TL;DR: In this paper, a powder microelectrode technique is employed in the detection of ultra-low concentrations of dopamine (DA), which can be adsorbed and thus preconcentrated on the inner surface of a carbon black packed powder micro electrode, and separation of the oxidation current peaks of DA and ascorbic acid (AA) reaches about 300 mV.
TL;DR: It was proved that strong intermolecular hydrogen bonds exist in L-FV-II, resulting in its water-insolubility, but there are not any aggregates or multiple-helix structure for L- fv-II in DMSO/0.25 M LiCl.
Abstract: α-Glucan (L-FV-II) and β-glucan (L-FV-I) were isolated from fruiting bodies of Lentinus edodes by extraction with 5% NaOH/0.05% NaBH4, then precipitation with 1 M acetic acid. The analysis results of Smith degradation, high-performance liquid chromatography (HPLC), infrared spectra (IR), (13)C NMR spectra, and optical rotation indicated that L-FV-II is α-(1→3)-D-glucan with slight (1→6) branch linkages, and L-FV-I is β-(1→3)-D-glucan containing 10% protein, and with branches. The weight-average molecular weight, Mw, number-average molecular weight, Mn, radii of gyration, (1/2), and second virial coefficients, A2, of L-FV-II in aqueous 0.5 M urea/0.5 M NaOH (obtained from diluting its solution in 1.0 M urea/1.0 M NaOH) and 0.25 M LiCl in dimethylsulfoxide (DMSO/0.25 M LiCl) were measured by light scattering, membrane osmometry, and size exclusion chromatography (SEC). The values of Mw and Mn for L-FV-II in 0.5 M urea/0.5 M NaOH are 24.1×10(4) and 10.9×10(4), respectively, similar to those in DMSO/0.25 M LiCl. It was proved that strong intermolecular hydrogen bonds exist in L-FV-II, resulting in its water-insolubility, but there are not any aggregates or multiple-helix structure for L-FV-II in DMSO/0.25 M LiCl. The chain of α-(1→3)-D-glucan is more extended in DMSO/0.25 M LiCl than that in the aqueous solution.
TL;DR: In this article, a synthesis of LiNiO2 by heat treatment of Li(OH)·H2O and Ni(OH2)2 is reported, which exhibits a considerably high discharge capacity of 145 mA h g−1 and a sufficiently long cycle-life when cycled over a lithium composition range.
TL;DR: This method has been successfully applied to the determination of sulfite in sugar and sulfur dioxide in air by using triethanolamine (TEA) as the absorbent material.
TL;DR: Although little sequence similarity exists between the above two short and two long peptides, they are similar at the positions of six cysteines, suggesting that they should all share a similar scaffold composed of an α‐helix and a three‐stranded β‐sheet.
TL;DR: The development in the analysis of inorganic cations as their complexes by capillary electrophoresis is reviewed in this article, where separation strategies, approaches of derivatization, choice of complexing ligands, manipulation of sensitivity and selectivity, and applications to metal speciation analysis are discussed.
TL;DR: In this article, the cyclic voltammetric behavior of Nafion and carbon-supported Pt-Nafion interfaces was studied by using the powder microelectrode technique.
TL;DR: In this paper, two chitosan derivatives were synthesized by the reaction of crosslinked chitosa with dibenzo-16-c-5 chloracetate crown ether and 3,5-di-tert-butyl dibenzzo-14c-4 diacetate Crown ether with the intent of forming polymers that could be used in hazardous waste remediation as toxic metal-binding agents in aqueous environments.
Abstract: Two novel chitosan derivatives—crosslinked chitosan dibenzo-16-c-5 acetate crown ether (CCTS-1) and crosslinked chitosan 3,5-di-tert-butyl dibenzo-14-c-4 diacetate crown ether (CCTS-2)—were synthesized by the reaction of crosslinked chitosan with dibenzo-16-c-5 chloracetate crown ether and 3,5-di-tert-butyl dibenzo-14-c-4 dichloracetate crown ether with the intent of forming polymers that could be used in hazardous waste remediation as toxic metal-binding agents in aqueous environments Their structures were confirmed with elemental analysis, infrared spectral analysis, and X-ray diffraction analysis In the infrared spectra of CCTS-1 and CCTS-2, the characteristic peaks of aromatic backbone vibration appeared at 1595 cm−1 and 1500 cm−1; the intensity of the NH and OH stretching vibration in the region of 3150–3200 cm−1 decreased greatly The X-ray diffraction analysis showed that the peak at 2θ = 20° decreased greatly in CCTS-1 and CCTS-2 The adsorption and selectivity properties of CCTS-1 and CCTS-2 for Pb2+, Cu2+, Cr3+, and Ni2+ were studied Experimental results showed that the two crosslinked chitosan derivatives had not only good adsorption capacities for Pb2+, Cu2+, but also high selectivity for Pb2+, Cu2+ in the coexistence of Ni2+ For aqueous systems containing Pb2+, Ni2+, or Cu2+, Ni2+, CCTS-1 only adsorbed Pb2+ or Cu2+ For aqueous systems containing Pb2+, Cr2+ and Ni2+, CCTS-2 had high adsorption and selectivity properties for Pb2+ © 1999 John Wiley & Sons, Inc J Appl Polym Sci 71: 2069–2074, 1999
TL;DR: In this article, the Hajeck-Renyi inequality is generalized to the case of negatively associated random variables, and the classical Marcinkiewicz strong law of large numbers for independent and identically distributed random variables is generalized.
TL;DR: A new algorithm based on genetic algorithm (GA) is developed for solving function optimization problems with inequality constraints and results show that its generality, precision, robustness, simplicity and performance are all satisfactory.
Abstract: A new algorithm based on genetic algorithm(GA) is developed for solving function optimization problems with inequality constraints. This algorithm has been used to a series of standard test problems and exhibited good performance. The computation results show that its generality, precision, robustness, simplicity and performance are all satisfactory.
TL;DR: Considering the pressure of increasing population, present barriers to alleviation of floods, droughts and water environmental problems have been carefully analyzed from the Chinese practical background as discussed by the authors, and existing barriers to sustainable development of water resources have to be removed.
Abstract: This paper addresses the water resources management problems in China. Considering the pressure of increasing population, present barriers to alleviation of floods, droughts and water environmental problems have been carefully analysed from the Chinese practical background. The discussions involve water resources and problems in managing water supply and demand in China. Due to very uneven distribution of precipitation in space and time, China frequently suffers from floods and droughts. But the coincidence of the rainy season with the warm season is favourable to crop production and thus results in high population density in the eastern part of China. In order to avert disastrous consequences of hydrological extremes—floods and droughts now and in the future—studying sustainable development of water resources in China is an imperative. Based on results of such studies, existing barriers to sustainable development of water resources have to be removed. A number of feasible measures adaptable to t...
TL;DR: Interpenetrating polymer network (IPN) coatings synthesized from castor-oil-based polyurethane (PU) with chitosan, nitrocellulose, or elaeostearin were coated on regenerated cellulose (RC) film.
Abstract: Interpenetrating polymer network (IPN) coatings synthesized from castor- oil-based polyurethane (PU) with chitosan, nitrocellulose, or elaeostearin were coated on regenerated cellulose (RC) film fo ...
TL;DR: In this paper, the discoloration of four dyes, C.I. reactive red 2, reactive black 8, basic red 13 and basic yellow 2, were induced by solar photolysis of ferrioxalate in aqueous solutions.
TL;DR: In this article, the authors show that with polyaniline in solution, the highest scan rate reaches instead of a few fractions of millivolt per second with the usual composite electrode device (CED), due to the dramatic decrease of the reaction volume, which corresponds to to of material, as compared to a few and a few milligrams for the usual CED.
Abstract: Cavity microelectrodes make it possible to study the electrochemical properties of powder materials over a large range of potential scan rates. With polyaniline in solution, the highest scan rate reaches instead of a few fractions of millivolt per second with the usual composite electrode device (CED). This is due to the dramatic decrease of the reaction volume , which corresponds to to of material, as compared to a few and a few milligrams for the usual CED. Screening over an extended spectrum revealed new electrochemical behaviors, and various characteristics vs. profiles are established. ©1999 The Electrochemical Society
TL;DR: In this paper, a cellulose/alginic acid (RC-AC) ion-exchange membrane was prepared by coagulating a blend of cellulose cuoxam and alginate solution.
TL;DR: In this article, the bases and phosphate groups of DNA backbone interacting with gold electrode surfaces play an important role in DNA immobilization onto gold electrodes, and it was found that dsDNA adsorbed firmly on gold surfaces lies strand-on in an ordered saturated monolayer, and ssDNA strands exist in a honeycomb-like form on the surfaces.
TL;DR: A fast responsive, thermosensitive poly(N-isopropylacrylamide) (PNIPA) hydrogel was obtained after cold-treatment of a swollen, untreated PNIPA Hydrogel at low temperature for 24 h, and exhibits a faster deswelling rate than untreated PnIPA hydogel.
Abstract: A fast responsive, thermosensitive poly(N-isopropylacrylamide) (PNIPA) hydrogel was obtained after cold-treatment of a swollen, untreated PNIPA hydrogel at low temperature for 24 h. After this treatment, the PNIPA hydrogel exhibits a faster deswelling rate than untreated PNIPA hydogel. This property is probably due to an enhancement of the regularity of macromolecular arrangement during the freezing process.
TL;DR: In this paper, the chemiluminescence (CL) of Ru(phen) 3 2+ was applied to HPLC determination of oxalic acid in spinach, and the detection limit was 6.2×10 −6 mol/l.
TL;DR: In this article, the formation and supermolecular structure of regenerated cellulose (RC) microporous membranes prepared by coagulating mixture solution of cellulose cuoxam and polyethylene glycol were investigated.
TL;DR: Five platinum group metals have been separated by high performance liquid chromatography (HPLC) using 2-(2-thiazolylazo)-5-diethylaminophenol (TADAP) as a precolumn derivatizing reagent, which was rapid, sensitive and simple.