最新刊期
卷 35 ， 期 2 ， 1996
- 摘要：in this paper, we investigated various traditional methods in the field of the programming correctness certification, and discussed especially the problem of the cerfifccation for object-oriented programming. We proposed the conception of class correctness and system correctness for the certification of object-oriented programming.
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发布时间：2023-12-11 - 摘要：For a connected graph G with girth of least five, it is proved in this paper that if, for each vertex v of G, the independence numbor of the subgraph reduced by the venices that are of distance two or three from v is not greater than two times the minimum degree minus three, then G has a dominating cycle.
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发布时间：2023-12-11 - 摘要：in this paper, a ADM-FEM operating spliting method with higher order-accuracy for 2D unsteady convection-diffusion equation is developed hosed on [1], which combines OUICK scheme with FEM with nine point isparameter elements.关键词： conviction-diffusion equation;higher order accuracy;FDM-FEM operator-spliting method
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发布时间：2023-12-11 - 摘要：We derive a alternative phragmen-Lindelof theorem for energy expressions of solutions of a biharmonic boundary value problem in a semi-infinite strip, i. e we prove enersy must either grow exponentially or decay exponentially with the distance from the finite end of the strip. For the case of decay, we also present a method of obtaining explicit upper bound of the total energy.
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发布时间：2023-12-11 - 摘要：in the frequency range of 10-5 to 104 Hz,the dielectric spectroscopy of polymers can be described using time domain parameters. The polarization response of dieletrics may be exeressed as the sum of several terms of Aεs exp[- (t/τ)α]. It is confirmed by experiments that α=1 in stochastic relaxation, and that α= 1/2 in free relaxation processes. When the static dielectric constant εs Is measured in low frequency using frequency domain method, the contribution of slow response to the polarization is presented as absorbing current. The latter leads εs to an uncertain value. Time parameter is shown to be a sensitive method and can detect the microscopic polarization down to 10-4. In polymer material, the component of slow response is shown to be related to the dopants and fabricating process.
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发布时间：2023-12-11 - 摘要：We apply for the first time renormalization group theory to a system with a first-order phase transition between opposite magnetizations driven linearly by an external magnetic field.The system is described by the large--N model with continuous symmetry and its dynamics is governed by the time-dependent Ginzburg-Landau model. We show explicitly that the driven transition is also governed by the zero-temperature fixed point, and obtain novel dynamic scaling forms for the magnetization and the structure factor. From these relations the scaling form for the area of hysteresis loop with corrections follows naturally. Numerical results agree excellently with the theoretical predictions.关键词：first-order phase transitions;hysteresis;change rate of external field;scaling relations;renormalization group
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发布时间：2023-12-11 - 摘要：Nanocrystalline TiO2 powders were prepared by sol-gel method. The structure and properties of the as-prepared TiO2 powder at different heat-treatments were studied by TG,DTA, XRD, TEM and IR techniques. As the powder was heat-treated at 350℃ .it grew into a bee tetragonal anatase structure. Also the TiO2 grains grow slowly. the average particle size of which was about 22 nm in TEM. A structure transformation from anatase to rutile occured and the grain of the powder coasened drastically while the powder was heat-treated at above 550℃.At 750℃ the structural transformation from anatase to rutile completed.
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发布时间：2023-12-11 - 摘要：An ICP spectrometry system has been employed to measure the contents of heavy metal elements in sediment cores collected from 4 sea areas of the the Mirs Bay. The metol elements can be separated into two kind. One of them is composed of Ph, Mn. Ni. Cr and Cd and the other is composed of Fe,Mg,Zn,Cu and Co. The distribution of their contents with the depth are also acquired. Using the data of sedimention rate at the four sampling sites, sediment polluted history have been evaluated.关键词：the Mirs Bay;sediment core;heavy-metal element;ICP spectrometry;polluted history
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发布时间：2023-12-11 - 摘要：This paper introduces a simple and direct method for the numerical solution to the characteristic equation in a step Index multi-mode optical fiber. The 281-lime-program takes up internal memory 8716 bytes and it 152 seconds computer execution time. The result is show to be reasonable and accurate.
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发布时间：2023-12-11 - 摘要：The relation of the compisition of PBT/PET blends and their glass transitiontemperatures, the effect of crystal phase separation on the compatibility, and the compatibility of the uncrystallized regions between lamella have been studied acconding tothe results of DSC and DMA’ It is shown that the crystal phase separation leads to thechange of composition of the uncrystallized regions, but does not lead to phase separatIOn’’关键词： poly (butylene terephthalate);poly (ethylene terephthalate);crystallization;phase separation;compatibility
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发布时间：2023-12-11 - 摘要：The hydroxides, sulphides and phosphates precipitates of Ni2+, Zn3+, Ph2+,Fe3+, Bi3+, Cr3+, Ce4+ are nced to investigate the effective factors of the apparent flotation activation energy (Ef). The main physical and chemical factors include: the type and form of the precipitates, the adsorbed form of the foaming agent on the precipitates,various foaming agent and the mode of flotation. The results indicate that the Ff of noncrystal line precipitates is lower than that of the crystal line the Ef of the hydroxides is lower than that of sulphides; for the chemical adsorption of foaming agent on the precipitate, the Ef is low; the Ef of LC-I for foaming agent is the lowest among three foaming agents (sodium lauryl surifate, sodium oleate and LC-I agent) and Ef of the cycloneaeration flotation is the lowest among three modes of flotation (conventional dissolved flotation, air diffusion flotation, cyclone-aeration flotation ) are used. Various inorganic precipitate flotation kinetic studies showed that the flotation of abovenentioned precipitates could be described by an first-order reaction equation.关键词： inoganic precipitates;flotation apparent activation energy;effective factors
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发布时间：2023-12-11 - 摘要：The Gauss functions were first adopted fo fit the square of the functions of the hydrogenlike atomic orbitals, and then the functions so obtained were used as the density basis functions to fit the electrodensity function in molecular. To calculate the coeffictients and exponents of the Gauss functions, and calculate the charge distribution of molecules, we designed the corresponding program to solve a series of intergral problems. A series of organic molecules were calculated with that program and got the atomic electronic population further the net atomic charge in some molecules were obtained.The calculated results show that there is evidently polar alternating property in nonconjugated system as conjugated systom. That the energy of organic molecule system waseffected by inductive effect was explained with the calculated results.关键词： electronic population;density function hensity function;polar alternatlin
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发布时间：2023-12-11 - 摘要：Caulerpin 1 was isolated from Algae Calogassa leuprieuii, Laurencia majuscula and Hypnea concornis, compound 2 upon hydrolization of compound 1 was obtained as brown crystals. Their structures were confirmed by spectral analysis. Bioassay showed that caulerpin is an effective plant growth regulator.
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发布时间：2023-12-11 - 摘要：Linear sweep voltemmetry has been used to study the electrochemical reac tion of Sin(Ⅲ) in molten equimolar NaCl-KCl on the Fe cathode. The results suggest that Sin(Ⅲ) ions is reduced to Sm(Ⅱ) on Fe electrode at the first step, subsequently reduced to Sin(O) and formed alloy with Fe on Fe electrode surface. The diffusion coefficients and diffusion activation energy of Sin(Ⅲ) in molten chlorides had been determined.关键词：samarium ion;electroreduction;molten salt
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发布时间：2023-12-11 - 摘要：Sheep anti human IgG antibody was immobilized by adsorption to the walls of polystyrens microtiter strips. Human IgG was biotinylated. Biotinylated human IgG and sample human IgG competed for the limited antibody on solid phase. After the immunoreaction was completed, biotin on solid phase can "catch" SA-Eu (Ⅲ) Eu (Ⅲ) fluorescent counts was measured on a time-resolved fluorometer with addition fluorescent enhancement solution. The range of the assay standard curve is 0. 625￣ 40. 0 mg/L.This method can be used to determine content of igG in urine. In addition, SA-Eu (Ⅲ) can be used as a general label.
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发布时间：2023-12-11 - 摘要：A novel unique bisesquiterpenoid, biatractylolide (1), together with two new sesquiterpenoids and other eight compounds was isolated from the Chinese traditional herb medicine Atractylodes marocephala Koidz, mp 210-212℃, (. 0. 02,CHCl3), molecular weight 462, formula C,.,H,C30H38 O4. The structure of (1) was elucidated by NMR, 1H-1HCOSY, HMQC, HMBC and ROESY and so on, and confirmed by Xray analysis.关键词： Atractylodes marocephala Koidz;bisesquiterpenoid;isolation;structure
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发布时间：2023-12-11 - 摘要：We confirm here that the DyF3,HoF3 and YbF3 with α-YF3 typed structure are due to p-type semiconductors by measurement of AC cobined with DC conductivity,and the characterization of relaxation from polarization.
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发布时间：2023-12-11 - 摘要：Two primers containing the Pst I site and Sal I site and stop codon respectively were synthesized and used to amplify a 232 hp DNA sequence coding for mature hIGF-1 protein with the 700 bp hIGF-1 cDNA fragment as template by Taq polymerase.The amplified DNA fragment was cloned into M13mp18 vector and sequenced by Sanger-s dideoxy chain termination method. The sequencing data show that the nucleotide sequence of the cloned fragment is the same as hIGF-1 coding sequence published and that we have successfully remoulded the hIGF-1 protein coding region with Pst I site at 5’ end and Sal I site and stop codon at 3’ end using the add-on PCR technique.
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发布时间：2023-12-11 - 摘要：The fossil wood-Piceoxylon dongguanensis sp. nov. was collected from the Late Cretaceous strata of Dongguan City, Central Guangdong. The strata also yield some macrofossil plants and abundant sporopollens of Late Cretaceous (Turonian) in age. The fossil wood represents a trunk base, about 4 m in length and ranging from 70 cm × 30 cm to 90 cm × 40 cm in size. Its periphery, about 2￣ 3 cm in thickness, being charcoalified, shows the internal structure of the secondary xylem, which is studied by scanning electron micrograph (SEM). In transverse sections, growth rings are somewhat distinct and the tracheids are square or polygonal in outline.The resin canals are small and separated from one to another. The bordered pits in the radial walls are seen to be in one row. The pits are small, elliptical, separated from each other. The pitwapertures are fusiform. some with pit membrane. Bars of Sanio absent. Medullary rays parenchymatous, some horizontal walls with spiral thickenings, abietinean pittings 1 ￣ 3 per field, oval or fusiform. In tangential sections only one uniseriate ray (3 cells in height) can be seen, no horizontal resin canals are preserved. There are some tracheids with spiral thickenings but without bordered pits
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发布时间：2023-12-11 - 摘要：A new species, Crenitis protuferans Jia is Teperted, and the genus Crecitis is firstly recorded in China. The species resembles CTecitis punctatostriata Letzn., but can be identified by with a small round protuberance on mesosternum, punctures on elytra sparesly lined, punctures on frontof sutural not larger than those of arround them, lateral margin of pronotum nearly straight and body less convex.Measurement: length 3. 1 ￣ 3. 3mm, width 1. 5￣ 1. 7mmHolotype allotype , paratypes 2 , 2 , Liangshui, Heilongjiang Province, 1977,VII 21 ￣ 30. Collected by Pn Zhelong. All type specimens are deposited in collection of Institute of Entomology, Zhongshan University.
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发布时间：2023-12-11 - 摘要：According to the tide table the protozoan communities were collected with PFU method at two stations in Pearl River, Guangzhou City. The samples which were collected in different tide periods respectively were observed qualitatively and quantitavely. After the data analysis and statistical comparision we find that the clonization and the functional parameters of protozoan communities are not influenced by tides in Pearl River, so that PFU Method is also suitable to be used on the water body with tides.
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发布时间：2023-12-11 - 摘要：A simple and rapid method was proposed for the isolation of total DNA and RNA from silicageldryed leaves as well as fresh leaves of various groups of plants. without special clearing treatments of solutions, glassware and plasticware, and the use of poisonous phenol. This method is fairely suitable for the isolation of DNA and RNA from collection of plant leaves dryed in silicagel in field Which is convenient for international exchange. The isolated total DNA and RNA can be applied effectively in PCR, sequencing. SnRNA studies and other molecular biological researches.关键词： efficient method;isolation;total DNA and RNA
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发布时间：2023-12-11 - 摘要：The diagenesis of late carboniferous carbonate rocks in the middle Yangtze area were mainly dolomitization, compaction pressure solution and dissolution, secondly recrystallization,cementation and locally dedolomitization, silification, desilification, pyritization, gypsification and degypsification. The various types of diagenesis were superposed, to different degrees, by karstification which could be identified by diagenetic composition, textures and structures. Based on the composition, textures and structures of diagenetics, oxygen and carbon isotopes, contents of minor elements and cathode luminescence of diagenetic components, the diagenetic environments could be distinguished into marin atmospheric fresh-water mix water and burial environment. During the formation and evolution of carbonate rocks, the superposition of different diagenetic environments and diagenetic types formed complicated diagenetic sequence and environmental association.
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发布时间：2023-12-11 - 摘要：By use of the daily data of severe local storm in Beijing area and Beijing’s sounding from April to September of 1980￣1988, the favourable conditions for the storm genesis are identified. They are (1) low pressure in the lower troposphere, (2) unstable stratification in the troposphere and POtential instability in the middle-low troposphere, (3) high vapour content in the lower troposprere and large relative humidity in a deep tropospheric layer. The storm genesis is independent of strong wind in high tropsphere, vertical wind speed shear and dryness in the middle troposphere.
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发布时间：2023-12-11 - 摘要：The selection of an optimum size and number of quadrat is very important to save time and obtain an estimate of biomass with a tolerable margin of error at a given level of confidence.the grassland and fernland of Hong Kong have been diScussed byUse of the Wiegert method and analysis of the edge effect as well as data from the past research Of tropical grassland. The results show that 1. 0 X 1. 0 m quadrat (1. 0m2) is an optimum quadrat size, and about & to 16 of them are required for a standard error within 10% of the mean. However, in fact, the harvested quadrat number or size in most studies of tropical grassland ate usually less than those mentioned above due to limits imposed by labour and time contraints.关键词： qrassland fernland;biomass;optimum size and number of quadrat;selection
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发布时间：2023-12-11 - 摘要：Tourism resources of the Mt. Danxia are evaluated by means of fuzzy synthetic appraisal. Based on characteristics of tourism resources of Danxia landfom, twelve evaluation factors of three groups are defined. Membership of implict numeric factors to each evaluation grade is derived from statistics of questionaire while that of explicit numeric’factors is calculated by devised membership functions. Weights of factors are classified into three grades corresponding to three groups, and each factor is distributed a different weight. Results of calculation show that the Danxia scenic spot tends to first two of the four evaluation grades. In addition, results derived from operators (。,+ )and (, V )agree well.
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发布时间：2023-12-11
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