最新刊期
卷 35 ， 期 4 ， 1996
- 摘要：A diffusion model of space charges in condensed dielectrics is used to explain the slow polarization effect. By separation of variables the diffusion equation is solved in a series form. When the time t is much smaller than the response time, the solution leads to a decay function exp( -t/τ ), which is in agreement with the empirical formula. But for larger t ,the decay function transforms into exponential form. A theoretical decay function is given as exp(- t/τ+at 2/τ 2) for t<2 5τ with a=3 613 52. When t≥2 5τ , the decay function is smaller than 0 67%, it is hardly to detect in measurement. A careful experiment for paraffin in room temperature shows that this is an excellent approximate formula.关键词：slow polarization effect;dielectric relaxation;diffusion equation;paraffin
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发布时间：2023-12-11 - 摘要：nitro 4′ (N,N′dihydroxyethyl) amino azobenzene and its three derivatives (R HANB)have been synthesized. In their “push pull” electron system, the electron transition between ground state and the intramolecular charge transfer state was observed by UV Vis spectra in polar solvents. Dealing with solvatochromic method, the composite values of the second order optical polarizabilities ( β CT )and the ground state permanent dipole moments( μ g)were obtained. The M+1 peaks of FAB Mass spectra for R HANB seem to berelated with the processes of thermal hydrogen transfer in their intra molecular charge transfer structures.
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发布时间：2023-12-11 - 摘要：The dynamic characters of concentration of radionucldes in freshwater fishes are studied. The experimental results are fit by a mathematical model to get characteristic parameters, such as concentration factors, elimination rate constant and concentration rate. Meanwhile, the relative concentration degree of radionulide 131 Ⅰ of different organisms in a fish is shown. The influence of various factors on migration characterristics of radionuclides in freshwater fishes are discussed. From the results of all the experiments for tilapias, the concentration factor CF lies in the range (2.29￣5.41) Bq\5kg -1 /Bq\5L -1 , and the limimation rate constant k lies in the range (0 0026￣0 0083)h -1
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发布时间：2023-12-11 - 摘要：The strictly convex operator and smooth operator are defined, it is shown that if T * is smooth operator, T is strictly convex operator and if T * is strictly convex operator, T is smooth operator.关键词：strictly convex operator;smooth operator;locally uniformly convex operator
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发布时间：2023-12-11 - 摘要：The left Besov spaces L α,q p (Σ) and right Bexov spaces R α,q p (Σ) are given by using Clifford analysis, where a∈R and 1≤p,q≤∞. Furthermore, we obtain two characterizations of the Besov spaces for 0<α<2关键词：Besov spaces;smooth molecule;Clifford analysis;Calderón Zygmund operator
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发布时间：2023-12-11 - 摘要：On the compact metric space (X,d) , an open map f is an Anosov map with the constant c>0 if and only if the shift map σ f:X f→X f is an expansive map with POTP.
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发布时间：2023-12-11 - 摘要：The author considers a class of nonlinear neutral differential equations (t)= g(t,x(t)) +f[t,x(t),x(t-△(t)),(t-△(t))] Where △(t) is a non negtive and unbounded function, and meets the condition (t-△(t))→+∞(t→+∞). The asymptotic stability criteria of the zero solution are obtained.关键词： quasi monotone increasing function;variation exponential;asymptotic stability;C (1) space
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发布时间：2023-12-11 - 摘要：A rectangular unconventional plate bending element(REUNC element) which is a match for the TRUNC element is presented. Although the displacement mode of the new element is the same as that of the ACM element, the REUNC element has the features of higher accuracy, simpler structure, less computing time and more easily programming. Therefore, it is the simplest and effective rectangular thin plate bending element, and will be of greater practical value.
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发布时间：2023-12-11 - 摘要：Bis iron(Ⅲ), bis manganese(Ⅲ) and bis cobalt(Ⅱ) porphyrins dimers linked by flexible alkoxyl chains have been synthesized and characterizaed by EA, IR, UV vis, 1H NMR and EPR spectroscopy. These binuclear complexes as model systems of cytochrome P450 are effective for the hydroxylation of cyclohexane with molecular oxygen under mild conditions and have better catalytic activities than the corresponding monomers. The catalytic activities of binuclear complexes decrease in following order: bis iron(Ⅲ)>bis manganese(Ⅲ)>bis cobalt(Ⅱ).关键词：porphyrin dimer;binuclear complexes;model system of cytochrome P450;hydroxylation of cyclohexane
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发布时间：2023-12-11 - 摘要：The stability constants of the binary complexes comprising Zn 2+ or Cd 2+ and 2 picoline, 2,4 lutidine or 2,4,6 collidine and ternary mixed ligand complexes containing in additional adenosine 5′ triphosphate(ATP) were determined by potentiometric pH titration in aqueous solution. Comparing these data with those of the corresponding complexes containing ammonia instead of pyridine like ligands, it has been found that an intramolecular stacking interaction exists between the pyridine like ligands and the purine moiety of ATP in the ternary complexes, and the interaction is related to the structure of coordination spheres of the central metal ions.
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发布时间：2023-12-11 - 摘要：This paper reports the crystallinity and tensile properties of sisal fiber (SF) after modification. The results show that the crystallinity and tensile properties of SF increases after treatment using concentrated caustic soda and acetic acid.
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发布时间：2023-12-11 - 摘要：In this paper, the various effects influencing activity and selectivity of catalytic esterification reaction of α pinene with acetic acid to form bornyl ester, including temperature, time, co catalyst, solvent and anion effect etc., have been studied. The better synthesis conditions in ordor to obain high yicld of bornyl ester is also given. The complex catalysis mechanism is presented that an acidic complex compound HB(AcO) 4 forms in HB solution system. It is the complex compound that affords active H + and B(AcO) - 4 in the solution, which influenecs the two distinet reaction mechanisms (ionizing and non ionizing) and controls the competitions between ring enlarging and ring opening reactions, between esterification and isomerization, so that the activity and selectivity in the formation of bornyl ester from α pinene and acetic acid are greatly improved. For all these results, the satisfied mechanistic explanations have been given.
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发布时间：2023-12-11 - 摘要：Two oleanane type triterpenes were isolated from the crude drug Lu Lu Tong, the fruits of Liquidambar formosana and their structures were elucidated as 2α,3β dihydroxy 23 norolean 4(24), 12(13) dien 28 oic acid(1), 2α,3β,23 trihydroxyolean 12(13) en 28 oic acid(2), based on 13 C NMR, DEPT, 1H NMR, 1H 1H COSY, 13 C 1H COSY, IR, MS and elemental analysis. (1) is a novel compound, while (2) is first isolated from this plant.关键词：Lu Lu Tong;pentacyclic triterpenes;oleanane;retro Diels Alder cleavage;2α;3βdihydroxy 23 norolean 4(24);12(13) dien 28 oic acid
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发布时间：2023-12-11 - 摘要：Ca, which was applied at the middle and late stages of hybrid rice Shanyou 63, could raise the contents of total chlorophyll and soluble protein, could increase superoxide dismutase(SOD)activity and could decrease the content of malondialdehyde(MDA) which is a product of membrane lipid peroxidation in flag leaves. In addition, Ca could also increase the effective panicle of plant, full grains per panicle, 1 000 grain weight and grain yield. It was preferable to apply 2 g CaCl 2 per pot than l g CaCl 2 per pot for ten days before heading and to apply the same amount of CaCl 2 in once than twice.关键词： leaf senescence;grain yield;Ca;hybrid rice
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发布时间：2023-12-11 - 摘要：The hypocotyl explants from Antirrhinum majus L. were cultured on MS agar medium with different plant growth regulator concentrations and combinations. Large differences were found in the responses of the hypocotyl explants. On the medium with 2,4 D(1～2 mg/L), the explants were found to produce healthy, viable and yellowish calli which did not differentiate to generate buds; but on the medium with 6 BA(2 mg/L) and NAA(0.2～0.5 mg/L),the explants produced healthy plantlets and yellowish calli. Shoots formed from the buds on MS agar medium supplemented with 6 BA(0.5～2 mg/L) and NAA(0～1 mg/L).These shoots, if transferred individually to MS agar medium with NAA(0.5～2 mg/L), produced roots at their bases. On the medium with NAA 0.5 mg/L, the roots of plantlets were healthy. Cytological observations indicated that the plant regeneration originated from epidermic cells of the explants.
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发布时间：2023-12-11 - 摘要：The mangrove community in Futian Nature Reserve, Shenzhen City, Guangdong province, is dominated by Aegiceras cormiculatum and Kandeha candel . The growth of these twoplant species was invcstigatcd by stem analysis. The mean annual incremcnt and cumulatlive incrcmcnt in tree height, stem basal and breast height diameter of thcsc two species were compared. The cumulative increment in biomass and trcc volumc was larger than that of the mcan annual incrcmcnt. The mean annual increment of these trees increascd with age, towards the peak values. Both species were about 20 years old and had rcachcd thcir mature slatus for some time.关键词： stem analysis;cumulative annual increment(CAI);mean annual incremcnt (MAI)
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发布时间：2023-12-11 - 摘要：During the binary division of Pseudourostyla cristata, the new adoral zone of membranelles(AZM) in the proter is generated from three parts, namely the membranelles assembled by the AZM primordium which connects with the posterior end of the old AZM to form a complcx, the old AZM lapel modified by cutting out about 25 membranelles from the anterior section and the old AZM collar whose several membranelles in both sides have disintegrated. The AZM membranelle number in the proter is regulated and controlled to an appropriate range by addition of new membranelles and reduction of some old ones. The same developmental programming of “addition and subtraction” is also applied to the morphogenesis of cells during physiological reorganization and cells in the 3rd and 4th cortical reorganizations during conjugation in P. cristata. This suggests that there would be simplification of genetical system of P. cristata in evolution, which is convenient for the genetic control.
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发布时间：2023-12-11 - 摘要：Shuidongling zinc copper ore deposit, which formed in Erlangping back arc basin in the early Palaeozoic Era, is situated in copper metallogenic prospect area and belongs to the typical Kurko type ore deposit. The metallogenic fluid is characterized by high K +/Na + and F -/Cl - and low CO/CO 2 ratios. The temperature, f O 2 , pressure and pH value of metallogenic fluid are 197～330℃, 3×10 -31 ～8.1×10 -33 Pa,77.97×10 5 Pa and 5.73～6.12 ( t =300℃) respectively. The isotopic features prove that metallogenic materials is derived from subjacent volcanics and the sulfur has a mixed sources (magmatic water plus seawater). In addition, the magma played a role in the mineralization.
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发布时间：2023-12-11 - 摘要：The content and racemization degrees of amino acids in fossil bones and teeth buried in some Quaternary deposits in Guangdong province and the Guangxi Zhuang Autonomous Region, and in Nanyue King′s mausoleum, were analyzed. The results show that proteins in fossils had been gradually degraded into free amino acids and shorter peptides with the increase of burial time, and the amino acid compositions also had been modified. Amino acids in fossils had continuously racemized since buried. Free, terminal and interion amino acids have different racemization rates, which explained why amino acid in various dialysis fractions had different racemization degrees. It can also be expected that amino acids racemization will deviate linear kinetics with the further hydrolysis of residual proteins in fossils.
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发布时间：2023-12-11 - 摘要：In order to define the critical value of correlative significance of contrast, a method of hypothesis test is presented, which has perfected the analysis technique of the contrast. By using the method and basing on a 0.05 signficance level, the genetic environment features of hard rain in summer were analysed and the favorable conditions were identified. They were compared with the existing idea of the middle latitudes and a rational supplements and modifications were made to the esisting ideas.关键词： contrast;Beijing area;hard rain;genetic environment
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发布时间：2023-12-11 - 摘要：Three management alternatives are proposed for the purpose of improving the water quality of drinking water supply sources in the Yodo River, Japan. THMP levels at two major intakes are calculated with the Cumulative Discharge Model. Carcinogenic risk of THM in drinking water which forms in the chlorination process of water purification is estimated by employing two different interpolation methods. The risk is evaluated and the effect of alternatives is discussed.关键词： river quality management;THM;risk assessment
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发布时间：2023-12-11 - 摘要：In this paper, we estimate the intensity and power of gravitational wave from collision of Comet SL9 with Jupiter, by a reasonable model. The result shows that intensity of the gravitational radiation is far under the sensitivity of the present detectors, as we can presuppose. Nevertheless, the calculations and results in this paper are enlightening.
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发布时间：2023-12-11 - 摘要：From an alcohol extract of Syrrhopoden japonicus (Bensch.) Broth. four compounds were isolated and identified as ethyl hematommate, gymnomitrol, (s) ( ) δ cuparenol and 3 friedelanone by spectral methods, respectively.
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发布时间：2023-12-11 - 摘要：From an alcohol extract of Syrrhopoden japonicus (Bensch.) Broth. four compounds were isolated and identified as ethyl hematommate, gymnomitrol, (s) ( ) δ cuparenol and 3 friedelanone by spectral methods, respectively.
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发布时间：2023-12-11 - 摘要：One new speises was described and new data of flowers or fruits of other three published species was complemented from genus Camellia by author.关键词：Camellia skogiana;new data of Camellia
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发布时间：2023-12-11 - 摘要：The KronigPcnney modet is used to study the resistance of a quasionedimensional disorder system. By using the transfermatrix technique, the resistance formula is derived.
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发布时间：2023-12-11 -
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