共查询到20条相似文献,搜索用时 31 毫秒
1.
Based on some pragmatic theories,this paper mainly analyzes how the markedness/unmarkedness works in the daily discourses. It isfound that markedness/unmarkedness are used alternatively which aims to express the deep meaning or the new information. 相似文献
2.
Z.X.Yang T.Zhang 《信阳师范学院学报(自然科学版)》1991,4(3):60-66
The chemisorption energy of hydrogen on semiconductor/alloy composite substrates are investigated. (?)g the conplex-energy-plane integration approach. The electronic properties of the substrate are described by using the Green function method within the framework of the tight-binding approximation. The coherent potential approximation (CPA) is used to deal with the alloys. specific calculations are performed for the H-ZnO/Ni_xCu_(1-x) and H-ZnO/Ag_xpd_(1-x) systems. 相似文献
3.
This research on the solvent effects of 2-methyl-4,5-dimethoxy-3-oxo-2H-pyridizine(MDOP) in binary solvent systems on the infrared spectra for MDOP in n-hexane/CHCl3 mixture solvents showed that there were three forms of carbonyl stretching vibration band[v(C=O)] of MPOP as mole fraction of CHCl3 in the binary solvents changes.In pure n-hexane solvent,the v(C=O) of MODP appeared at a relatively high wavenumber.With CHCl3 added,the v(C=O) shifted to lower wavenumbers.Two new bands were observed over a certain range of mixture solvent compositions.The origin of the bands was discussed in the terms of two kinds of hydrogen bond together with their individual dependence on mixture composition.COmparisons were drawn for the solvent sensitivities of v(C=O) for propanone. 相似文献
4.
Trace element geochemistry during chemical weathering——As exemplified by the weathered crust of granite, Longnan, Jiangxi 总被引:2,自引:0,他引:2
《科学通报(英文版)》1999,44(24):2260-2260
The granite weathering in Longnan, Jiangxi, is represented by mineralogical changes of feldspars → montmorillonite, illite → kaolinite, halloysite f66 bauxite, with Na, Ca, Si, P, V, U and Sr being in a mobile state while Ti, Al, Fe, Sc, Th, Zr and Hf remaining relatively conservative. With the exception of Zr/Hf, Nb/Ta, Th/Sc, Zr/Nd and Sm/Nb, changes are notable in ratios between most of the trace elements. Re-distribution of REE and Y has taken place during the chemical weathering, and the REE patterns of weathered samples in the profile, with original characters of the parent rock still recognizable, has undergone some fractiona-tion. Generally, the extent of chemical weathering is the critical factor determining the mineralogical and chemical characteristics of the profiles and this must be taken into account in any study of tracing the provenance on the basis of mineralogical and trace element characteristics of the sediments. 相似文献
5.
The consolidation behavior of mixed in place cement-and lime /cement-mixed column was studies.COnsolidation of the composite foundation was modeled as a three-dimensional axi-symmetric problem.The authors used the finite difference method to obtain the pore pressure variation with time at and location below the surface.A computer program developed by the authors was used to draw some interesting conclusions about the consolidation behaviors of cement-mixed pile foundation.Finally,a combined model including the permeability coefficients of cement-mixed piles and soil,was studied and its feasibility was evaluated. 相似文献
6.
MENGJinhong ZHANGHui DavidG.Evans DUANXue 《科学通报(英文版)》2005,50(8):745-751
Two different interlayer structured glyphosate(GLY) intercalated MgAI layered double hydroxides, as novel pesticide slow/controlled release materials, have been synthesized by co-precipitation method under various reaction pH values. The slow/controlled release properties have been tested in Na2CO3 aqueous solution. The release mechanism has been interpreted on the basis of the ion-exchange between the guest GLY anions in the lamellar host and CO3^2- in the release media, and the diffusion process of GLY anions in the interstice and interlayer of GLY intercalates, i.e.diffusion through the particles, is the rate-limiting step of GLY release process. The GLY intercalate assembled at lower pH, possessing higher interlayer gallery height and vertical monolayered arrangement of guest anions in the interlayer with larger packing density, exhibits better slow release property than that assembled at higher pH. The results reveal that the layered double hydroxides have potential application in the pesticide slow/controlled release area. 相似文献
7.
New Criticism is an approach to literature which was developed by a group of American critics, most of whom taught at southern universities during the years following the First World War. The New Critics wanted to avoid impressionistic criticism, which risked being shallow and arbitrary, and social/historical approaches which might easily be subsumed by other disciplines. Thus, they attempted to systematize the study of literature, to develop an approach which was centered on the rigorous study of the text itself. They were given their name by John Crowe Ransom, who describes the new American formalists in The New Criticism (1941). 相似文献
8.
‘Lenses By Mail’(http://lensesbymail.com/index.htm) and ‘Postoptics’(http://www.postoptics.co.uk/) are listed in the ‘googles' search web-page for contact lenses.Both the companies are based in the UK and are online global suppliers of eye care products,mainly replacement contact lenses.Lenses By Mail is a subsidiary of Warren Enterprises Inc.and claims to be a leading discounted contact lens supplier.Postoptics is the mail order division of Viewpoint,one of the largest contact lens practices in the UK,and claims to be the UK’s No.1 mail order contact lens company。 相似文献
9.
Aeromonas hydrophila (A. hydrophila) 4AK4 produced poly (3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBHHx) with an almost constant 3-hydroxyhexanoate (3HHx) content of 10 % - 15 % from lauric acid and/or soybean oil. Both A. hydrophila 4AK4 and recombinant Escherichia coil (E. coil) JMU193(pBH32) produced PHBHHx with controllable 3HHx content when fed lauric acid and another co-substrate. With glucose or gluconate as the co-substrate, the 3HHx content in the copolyester produced by A. hydrophila 4AK4 was reduced slightly from 12% to 9%. However, the 3HHx content in the copolyester produced by E. coll JMU193 (pBH32) was significantly reduced from 9% to 2% with fructose as the co-substrate. These results show that regulation of 3HHx content in PHBHHx can be achieved using genetically engineered E. coll. 相似文献
10.
HUANGZhimin SHIGaoquan ZHANGJiaxin HONGXiaoyin 《科学通报(英文版)》2003,48(5):434-436
Poly (p-phenylene)(PPP) microtubules with diameters of 0.2-0.8μm and lengths of -10μm have been synthesized by direct oxidation of benzene in the mixed electrolyte of boron trifluoride diethyl etherate(BFEE)and trifluoroacetic acid(TFA)(BFEE:TFA=2:1,by volume),containing a certain amount dodecylbenzene-sul-fonate(SDBS)as surfactant.The microtubules were grown vertically on the working electrode surface.The tubular morphology has been confirmed by scanning and transmission electron microscopies and the chain structure of the skin of the tubules has been characterized by Raman spectros-copy.The electrode property,monomer/surfactant molar ration and the value of applied potentical have strong effects on the morphology of the microtubules. 相似文献
11.
Like Cinderella in the fairy tale Cinderella, Carrie is beautiful, innocent and poor. But unlike the traditional Cinderella who mindlessly waits around for a handsome prince to come to her rescue, Carrie, the aspiring Cinderella, resolvedly leaves the men she ever depended on and eventually becomes a successful actress. Sister Carrie, the most impressive heroine of Theodore Dreiser, is a contradictory character. Some accuse her of realizing her ambition with immoral means. However, some others take sympathy with her courage, determination, and aspiration.
By analyzing the most distinguished quality of Sister Carrie -her aspiration, this essay is to illustrate from the perspective of feminism that women are not limited by their sex. Ignoring her own sex as well as the conventional attitude toward women in a maledominated society, sister Carrie, full of aspiration, takes an active part in creating and determining her own lives and her own futures. 相似文献
By analyzing the most distinguished quality of Sister Carrie -her aspiration, this essay is to illustrate from the perspective of feminism that women are not limited by their sex. Ignoring her own sex as well as the conventional attitude toward women in a maledominated society, sister Carrie, full of aspiration, takes an active part in creating and determining her own lives and her own futures. 相似文献
12.
The adsorption of Sulphonated polyacrylamide(PAMS)on ilmenite and feldspar fromaqueous solution and the floeculation of minerals by PAMS have been studied.The researchresults reveal that the strong adsorption of PAMS on ilmenite results in its strongflocculation and the weak adsorption of PAMS on feldspar causes its dispersion to be morestable.The mechanism of PAMS bonding is discussed in terms of co-ordination and H-bonding interaction respectively in the light of molecular orbit.The co-ordination between—So_3~- on PAMS chain and sites of Ti~(4+) or Fe~(2+) on ilmenite was testified by electron spec-troscopy(PHI550ESCA/AES).Consequently new technology“Bulk flocculation-magneticsepa-ration-ultrasonic deflocculation-magnetic separation”for fine ilmenite/titano-magnetite/feld-spar system has been successfully developed. 相似文献
13.
屠一锋 《苏州大学学报(医学版)》1993,(2)
The formulas of current of first and second derivative of differential pulse polarography (DPP) which has been deduced in this paper indicate that derivative may be enhance the sensitivity of DPP. By the analogy/data transformation、smoothing、and numerical differentiation, we can obtain the derivative current of DPP. 相似文献
14.
Utilizing Statistical Semantic Similarity Techniques for Ontology Mapping——with Applications to AEC Standard Models 总被引:2,自引:0,他引:2
The objective of this paper is to introduce three semi-automated approaches for ontology mapping using relatedness analysis techniques. In the architecture, engineering, and construction (AEC) industry, there exist a number of ontological standards to describe the semantics of building models. Although the standards share similar scopes of interest, the task of comparing and mapping concepts among standards is challenging due to their differences in terminologies and perspectives. Ontology mapping is therefore necessary to achieve information interoperability, which allows two or more information sources to exchange data and to re-use the data for further purposes. The attribute-based approach, corpus-based approach, and name-based approach presented in this paper adopt the statistical relatedness analysis techniques to discover related concepts from heterogeneous ontologies. A pilot study is conducted on IFC and CIS/2 ontologies to evaluate the approaches. Preliminary results show that the attribute-based approach outperforms the other two approaches in terms of precision and F-measure. 相似文献
15.
This paper introduces a frequency-hopped (FH) communication system to anti-intersymbol interferences (ISI) caused by the multipath propagation in shallow-water acoustic channels, and uses high-speed digital signal processor (DSP) and serial ADC (MAX121) chip to demodulate re-ceived signal efficiently based Fast Fourier Transform (FFT) algorithm. The field experimental results show: a data rate of 1Kbit/s with the bit error rates on the order of 10^-4 is denmnstrated at 2000 m in the shallow-water acoustic channel of Xiamen harbor, and the key techniques of the system is analyzed in the paper. 相似文献
16.
Response surface methodology (RSM) is used to optimize the medium of Tetraselmis sp.-1 which is cell fused microalgae capable of growing under mixotrophie condition. Empirical models are developed to describe the relationships between the operating variables (glucose, urea, sodium dehydrogenate phosphate, sodium chloride) and responses (cell density). Statistical analysis indi-cates that glucose and urea have significant effects on the microalgae cell density, but other two factors (sodium dehydrogenate phosphate, sodium chloride) have no obvious effect. The path of steepest ascent is used to approach the optimal region of medium ecanposition. Optimal cell density(2. 638 g dry weight/L) was reached when the operating conditions were glucose concentration(30.75 % ), urea concentration (0.440 g/L), sodium dehydrogenate phosphate (15mg/L) and sodium chloride (28 g/L). 相似文献
17.
Molten Carbonate Fuel Cells(MCFC) are produced with a highly efficient and clean power generation technology which will soon be widely utilized.The temperature characters of MCFC stack are briefly analyzed.A radial basis function (RBF) neural networks identification technology is applied to set up the temperature nonlinear model of MCFC stack,and the identification structure,algorithm and modeling training process are given in detail.A fuzzy controllery of MCFC stack is designed.In order to improve its online control ability,a neural network trained by the I/O data of a fuzzy controller is designed.The neural networks can memorize and expand the inference rules of the fuzzy controller and substitute for the fuzzy controller to control MCFC stack online,A detailed design of the controller is given,The validity of MCFC stack modilling based on neural networks and the superior performance of the fuzzy neural networks controller are proved by Simulations. 相似文献
18.
Microorganisms are commonly used to transform chemicals to chiral compounds. Pseudomonas cepacia 1813, Pseudomonas stutzeri 1317, Saccharomyces cerev isiae 1912, and 5 Escherichio coil strainswere used to transform acetophenone to 2-phenylethanol. The results show that the E. coli strains have the poorest biotransformation ability. P. stutzeri 1317 provides the best transformation ability with a transformation rate of 30% achieved with either whole or broken P. stutzeri 1317 cells for a reaction pH of 8. 2 and an initial acetophenone concentration of 2 g/L. An acetophenone concentration of 10 g/L strongly inhibits the biotransformation for a pH of 8. 2. Crude alcohol dehydrogenase obtained from S. cerevisiae 1912 transforms acetophenone to 2-phenylethanol when nicotinamide adenine dinucleotide reduced (NADH) is added. 相似文献
19.
On the development of the GRAPES——A new generation of the national operational NWP system in China 总被引:9,自引:4,他引:5
ZHANG RenHe SHEN XueShun 《科学通报(英文版)》2008,53(22):3429-3432
Numerical weather prediction (NWP) has become one of the most important means for weather forecasts in the world. It also mirrors a nation's comprehensive strength in meteorology. In 2000, China Meteorological Administration (CMA) established the National Innovative Base for Meteorological Numerical Prediction in the Chinese Academy of Meteorological Sciences (CAMS), to work on developing a new generation of the national operational NWP system-Global/Regional Assimilation and PrEdiction System (GRAPES), to enhance meteorological services in China in the new century. In recent years, the GRAPES has witnessed a fast development. The GRAPES has been set up as an integration of the model framework, data assimilation, regional and global NWP system, which can be commonly used for both operation and research. In this paper, a brief review is made for illustrating the GRAPES system, including the advanced designs of the GRAPES, its diverse applications in multi-fields, and efficiencies of the regional and global GRAPES in operational applications based on hindcast results. 相似文献
20.
A modified selectively-infective phage(SIP) is developed to facilitate the selection of interacting antibody-antigen paris from a large single-chan antibody(scFv)library in vivo.The system is constructed with a modified helper phage M13KO7 and phagemid pCANTAB 5E.The antigen fused to the C-terminal of N1-N2 domain and the scFv to the N-terminal of CT domain of the gIIIp of filamentous phage are encoded on the phage and phagemid vectors respectively.The phages produced by co-transformants restore infectivity via interaction between antigen and antibody fusions in the cell periplasm.In a model system,the scFv fragment of the anti-hemagglutinin 17/9 antibody and its corresponding antigen are detected in the presence of a 10^5 fold excess of a non-interacting cotrol paris,which demonstrates this system to be very sensitive and facile to screen a large single-chain antibody library. 相似文献