最新刊期
卷 51 ， 期 4 ， 2012
- 摘要：The current status and recent progress of dark matter indirect detection and collider detection experiments are briefly reviewed. The main results and constraints of new experiments are shown. Since 2008, anomalous excesses of cosmic-ray electron and positron spectra have been reported by several experiment collaborations. Despite of some arguments, these excesses can be explained naturally by dark matter effect. On the other hand, both antiproton to proton ratio and gamma-ray results show no anomalous signal and give strong constraints on dark matter. Additionally,constraints on dark matter can be derived from the zero signals from collider detection experiments. In the near future, new results of AMS-02 and LHC may give us some inspirations for dark matter researches.关键词：dark matter;indirect detection;collider detection;weakly interacting massive particle
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发布时间：2023-12-11 - 摘要：According to the meshing mathematical model of rolling coupling with the method of whole coupled matrix, the rolling coupling-rotor system coupling vibration equation was established. And combined with examples, the dynamic responses of the rolling coupling under the condition of different torques transmission was calculated to reveals the dynamic rules of the rolling coupling rotating at high-speed. The results show that, when the transmission torque is low (range from 1 N·m to 100 N·m), at high speed rotation, the transmission stability of rolling coupling is sensitive to the torque and the performances of driving is poor. But in this range, the amplitude is decreased sharply while the torque is increasing, which facilitates the coupling quickly adjust to the relative stable transmission state. When the rolling coupling running at high-speed with large torque, the amplitude variation is small and the performances of driving is good. Along with the increase of torque, the amplitude of variation becomes smaller and tends to be stable to the end, which implies that the rolling coupling is sutiable for the system working under heavily and unstablly torque. The reuslts also indicate that the mutual influence of the amplitude of the nodes each on the left-coupling and right-coupling is very small, so the rolling coupling can isolate the adverse vibration transferring between systems, which is in favor of multi-rotor system maitaining stable operation.关键词：rolling coupling;coupling;dynamic characteristics;whole coupled matrix method
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发布时间：2023-12-11 - 摘要：According to the durability test of concrete, and in order to meet the requirements of stress loading affected on concrete by multi coupling factors, a new loading device which takes account of ion erosion concrete under multi coupling factors was designed, made, and used to test the durability of concrete. The new device adopted the advantages and avoided the disadvantages of existing devices in China and foreign countries. The test results show that the new device has many excellent characteristics such as high loading accuracy, small stress losses, simplicity of operation, low cost and can be used for lots of test. The new device has gained national patent certificate of China, and may provide references for the research of concrete durability关键词：concrete;durability test;loading device
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发布时间：2023-12-11 - 摘要：The survey of unit type curtain wall is researched. Using the ANSYS software, the internal force and displacement of the unit type plate structure which are composed of the trough type aluminum plate and 5 stiffening ribs (portal type frame) are calculated. The stiffening rib and the aluminum plate corner partial rivet loosens by the rigid joint turns the hinge point is studied. The computation model is built and its biggest internal force and displacement are obtained. Finally, the practical application is introduced.关键词：unit type curtain wall;aluminum plate;stiffening rib;internal force;displacement.
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发布时间：2023-12-11 - 摘要：All-reflective interferometric autocorrelation is advantageous for the measurement of ultrashort pulses within UV to X-ray region or wideband pulses. By means of numerical simulation, comparison of the signal characteristics between the conventional and the all-reflective interferometric autocorrelations is made for ultrashort pulses with varied spectral phases. Femtosecond pulses from a Ti:sapphire laser as well as the chirped pulses stretched by a 40-mm-thick BK7 glass are measured by a home-made combined interferometric autocorrelator. The results show that the traces of two interferometric autocorrelations are quite similar for the same test pulses. Therefore, in situations that conventional autocorrelation is incapable or inconvenient for pulse measurement, all-reflective interferometric autocorrelation is competent to carry out the duties.关键词：nonlinear optics;measurement of femtosecond pulses;interferometric autocorrelation;all-reflective
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发布时间：2023-12-11 - 摘要：A vanishing theorem of genus g GW-invariants of blow-ups of arbitrary symplectic manifolds is proved with utilizing the degeneration formula of GW-invariants.关键词：symplectic cut;blow-up;degeneration formula;GW-invariant;relative GW-invariant
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发布时间：2023-12-11 - 摘要：Matching counting theory is the core of graph theory. Since it has important applications and is in connection with other theoretic problems closely, it has been studied extensively.And many celebrated results have been established. But the problem of counting the number of perfect matchings for general graphs isNP-hard. By applying differentiation, summation and rerecursion calculation, several counting formulas of the perfect matchings for five specific types of graphs are given. The number of all perfect matchings of many bipartite graphs can be calculated with this method.关键词：perfect matching;linear recurrence relation;chessboard
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发布时间：2023-12-11 - 摘要：The monotonicity of zeros of Pollaczek polynomials Pλn(x;a,b) about the parameterλand the interlacing properties of zeros of Pλn(x;a,b), Pλ+1n－1(x;a,b) and Pλ+1n(x;a,b) are investigated.关键词：Pollaczek polynomials;the interlacing properties of zeros;orthogonal polynomials
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发布时间：2023-12-11 - 摘要：Definition of uniform integrability of mean-square Henstock integral for the sequence of fuzzy stochastic process is introduced.A necessary and sufficient condition of uniform integrability of mean-square Henstock integral for the sequence of fuzzy stochastic process is studied. Finally, convergence theorem is obtained.关键词：second-order fuzzy stochastic process;mean-square Henstock integral;uniform mean-square Henstock integral
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发布时间：2023-12-11 - 摘要：The sub-super solution method is used to research the existence of large solutions of the quasilinear ellipticp-Laplacian system which is exponential. The existence and sufficient conditions of large solutions of the quasilinear ellipticp-Laplacian system are discussed. The key point is to establish a set of inequalities which have solutions to get the sufficient conditions.The sufficient condition of the quasilinear ellipticp-Laplacian system is obtanined, which is (a-p+1)(e-q+1)关键词：quasilinear ellipticp-Laplacian system;weak comparison principle;sub-super solutions;large solutions
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发布时间：2023-12-11 - 摘要：By using generalized Riccati transformation technique and functions of the formH(t,s), new oscillation criteria are established for third-order nonlinear dynamic equations on time scales of the form (a(t)［(r(t)xΔ(t))Δ]γ)Δ+f(t,x(τ(t)))=0.关键词：third order dynamic equations on time scales;oscillation;nonlinear;generalized Riccati technique
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发布时间：2023-12-11 - 摘要：The zeolite loading nano-CdS particles (M-CdS) were prepared by situ-reaction between CdCl2absorbed in zeolite and Na2S solutions, and then were used to modify PE in order to get functional polymer composites. The optical properties and crystallization behavior were characterized by UV-Vis, PL and DSC analyses, respectively. The results showed that PE/M-CdS composites exhibited an obviously fluorescence emission in 540~550 nm, the emission shifted to longer wavelength and the intensity improve first, and then became weak with the increase of M-CdS contents. But the absorption strength between 280 nm and 325 nm in UV-Vis spectra of PE/M-CdS composites increased with the increment of M-CdS contents, at the same time the crystallization degree and melt enthalpy decrease. M-CdS showed the heterogeneous nucleation effect on PP/M-CdS composites, which displayed a higher crystallization temperature than PP.关键词：zeolite;polyethylene;CdS;optical properties;composites
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发布时间：2023-12-11 - 摘要：Synthesis of naphthyl substituted malonyl-derived (Box) and pyridine-based bisoxazolines (PyBox) as well as their applications in the asymmetric allylic oxidation of cyclohexene witht-butylp-nitroperbenzoate have been carried out, with significantly improved reactivity (75%) while maintaining very good enantioselectivity (85%) using the ligand with 1-naphthyl group as the side chain on oxazoline ring.The correlations between the nature of the substituents on the bisoxazolines and the reactivity/selectivity have been established.关键词：chiral bisoxazoline-copper;allylic oxidation;asymmetric catalysis
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发布时间：2023-12-11 - 摘要：In order to compare the volatile constituents between Houyanling koufuye and its single herbChrysanthemi indici flosandClematidis radix et rhizomethe volatile oils of Houyanling koufuye were taken from preparation process, andChrysanthemi indici flosandClematidis radix et rhizomewere extracted by water steam distillation. Their structures were analyzed by GC – MS analysis. The relative contents of the components were calculated with peak areas normalization method. The result indicated that there were 24, 34 and 27 volatile constituents in essential oil of recipe Houyanling koufuye,Chrysanthemi indici flos,Clematidis radix et rhizoma,respectively. Their contents in volatile oils were determined to be 98.14%, 81.95% and 93.64%, respectively. The contents of volatile oils were different between Houyanling koufuyeChrysanthemi indici flosandChrysanthemi indici flos.
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发布时间：2023-12-11 - 摘要：PM2.5and PM10were monitored simultaneously by continuous online measurement instruments from July 8 to July 22, 2009 in Shantou, Chaozhou, Jieyang of Guangdong Province. The results showed that concentrations of PM2.5and PM10in the three cities of eastern Guangdong were lower than some coastal cities. PM10and PM2.5exhibited two peaks in a day, which were from 6 to 10 a.m. and from 18 to 22 p.m., respectively. The daily averaged concentrations of PM10and PM2.5fluctuated in a cycle of about 3 or 4 days. The portions of PM2.5were larger than those of other particles in sizes from 2.5 μm to 10 μm. The ratio of PM2.5to PM10was 0.521 5 in the three cities, in which measurements were carried out.
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发布时间：2023-12-11 - 摘要：This study was conducted to optimize conditions for crude proteases activity fromBacillus subtilisGS-1 by Plackett-Burman (PB) design and response surface methodology. Meanwhile, potential applications of proteases in protein hydrolysis were also determined. Three significant variables (NH4Cl, initial pH value and cultural temperature) necessary for the enhancement of proteases activity were selected by using PB design. Furthermore, an empirical model was developed to describe the relationships between these tested variables. Maximum enzymatic activity was attained at 372.814 U/mL, with NH4Cl at 3.768 g/L, pH at 5.6 and temperature at 22.4 ℃. Results of hydrolysis experiments indicated that the protease more prefer to hydrolysis proteins from animal source than that from plant source. The protease was prone to hydrolyze chemical bond that composed by amino acids of Glu, Val, Ile, Leu, Phe or Arg, and had great potential for applications in protein hydrolysis.
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发布时间：2023-12-11 - 摘要：From Nov. 2008 to Jun. 2010, an ecological investigation on Hexapoda was carried out in rice habitat and non-rice habitat in Agricultural Technology Extension Station, Zhuhai, Guangdong Province. A total of 78 species of Hexapoda, which belong to 57 familes, 10 orders, were obtained. The results show that Diptera and Homoptera are dominant in rice field, but only Diptera is dominant in weeds during rice growing. Diptera and Hemynoptera are dominant inItalian ryegrassfield in winter. However, Hemynoptera, Thysanoptera and Diptera are dominant in weeds. Shannon-Wiener diversity index (H) is 2.30~3.20. Pielou-evenness (J) is 0.72~0.86, but the value would be changed when rice maturing. Simpson dominance index is below 0.25. There is no distinct difference on the three indices between rice growing season and winter time. Jaccard similarity index is higher inItalian ryegrassfield and control field during rice growing, but higher inItalian ryegrassfield and weeds in winter.
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发布时间：2023-12-11 - 摘要：The anticoagulant activityin vitroof three different sample isolated from the leechHirudinaria manillensiswith three different extracting methods was studied, and utilized the optimal extracting process, the anti-thrombin bioactivity of five species of leeches were analyzed, and compared the anti-thrombin bioactivity of three species of wildH. manillensisfrom different geographical distribution and two species of culturedH.manillensisreared with different diets. The results showed that among them, the extracts produced by acetone precipitation had the highest yield, and also displayed the stronger anticoagulant activity tested than others (P<0.05). The test displayed three species of non-bloodsucking leeches (Whitmania pigraWhitmania acranulataandWhitmania laevis) had no or lower anti-thrombin activity, and the two species of blood-sucking leeches (H.manillensisandHirudo nipponia) had higher anti-thrombin activity, and that the anti-thrombin activity ofH. manillensiswas higher thanHirudo nipponiasignificantly (P<0.01). There was no significant difference of inhibitory activity to thrombin between wild and culturedH. manillensis(P>0.05). In conclusion, the leech ofH. manillensishad high anti-thrombin bioactivity in vitro, and the artificial breeding had no adverse effect on its quality and anticoagulant activity.
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发布时间：2023-12-11 - 摘要：To analyze genetic diversity and phylogeny of Gracilariaceae (Gracilariales, Rhodophyta). We compared ITS（including 5.8S rDNA） sequences of twenty three populations of fiveGracilariaandGracilariopsisspecies (Gracilariaceae, Rhodophyta), with the ITS sequences of 16 Gracilariaceaen species downloaded from GenBank database. The result showed that the length of ITS sequences of Gracilariaceae varies from 893 to 1 508 bp. The interspecific genetic distance ranges from 0.041 to 0.600; the intraspecific genetic distance ranges from 0.000 to 0.012, the former is much higher than the latter. Two main lineages of Gracilariaceae were from:Gracilaria\HydropuntiaandGracilariopsis/Gracilariophila. 5.8S sequences of Gracilariaceae has low variation among species and among populations, but the distinct sites were found among the genera and can be used on genus level or above. There are 9 mutant sites that can be used to distinguish the populations ofG. vermiculophyllafrom China, Russia and USA.关键词：Gracilariaceae;Gracilaria;Gracilariopsis;ITS;5.8S rDNA;phylogenic
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发布时间：2023-12-11 - 摘要：Gynogenesis is the production of an embryo from an egg after penetration by a spermatozoon that does not contribute genetic material. The process of gynogenesis involves two steps: firstly, the sperm is inactivated by UV irradiation;secondly, the meiotic diploids are made by restraint of the extrusion of the secondary polar body. Gynogenesis was induced in two groups of Russian sturgeon (Acipenser gueldenstaedtii) by cool shock and heat shock respectively. Cool shock (M1) and heat shock (M2) gynogensis offspring were gained separately. Six polymorphic microsatellite markers were used to investigate genotype by PCR amplification. Twenty fries in each group including gynogenetic families M1 , control group and their parents and forty fries in gynogenetic families M2 were chose to be analyzed .The average expected heteroaygosity (He), allele number(A) and allele frequencies(P) in the cool shock line was 0.591, 6.0 and 0.100~0.708 respectively. In the heat shock line, the average expected heteroaygosity, allele number and allele frequencies was 0.687, 5.5 and 0.006~0.774 respectively. Special microsatellite bands of male parent were used as diagnostic markers to analyze the hybrid of gynogenesis offspring. The results showed that 40 % in cool shock genogenesis offspring and 27.5% in heat shock genogenesis offspring were hybrid respectively. And, it is consistent with phenotypic identification results. Haploid individuals were identified in 10% of cook shock group and 15% of heat shock group. Complete gynogenetic progenies were found only in heat shock group, and they were just about 22.5%.Gene recombination in different levels were found in other offspring except haploid,hybrid and gynogenisis offspring of two gynogenetic lines.
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发布时间：2023-12-11 - 摘要：This paper mainly discusses the recognition and development of basic ideas of modern geomorphology. Based on the summary of traditional geomorphology theory and research achievements in modern geomorphology, it puts forward a new explanation on the meaning of landform and integral view of geomorphic system. Landform is an interrelated and co-adapted entirety, composed of morphology, composition materials, geomorphic process and boundary conditions. This new interpretation of landform is different from the traditional genetic mode, which regards landform as a function of geologic structure, agent and time.This paper does not suggest that time as a factor of geomorphic evolution, then, it can provide a new understanding on the statement that landform is a complex of four-dimensional space which consists of three-dimensional space and time. In this study, geomorphic evolution is a “non-equilibrium state” process, which is caused by the maladjustment among the four geomorphic elements, and time is not the drive power of geomorphic evolution. The “geomorphic equilibrium state” does exist in nature, which is also the basis of quantitative research in modern geomorphology. Boundary conditions are critical factors that control the geomorphic evolution process, and geomorphic evolution direction is decided by original geomorphic features and boundary conditions.关键词：basic ideas of geomorphology;integral view of geomorphic system;geomorphic boundary conditions;geomorphic evolution;geomorphic equilibrium state
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发布时间：2023-12-11 - 摘要：Urban wetlands play a significant role in the sustainable development of the urban eco-environment. The time-spatial evolution character and rules of the wetland landscape pattern in Wuhan were quantitatively analyzed using landscape ecological methodologies. The following results have been obtained：① The decrease in urban wetland area was 137.50 km2and in natural wetland area was 281.87 km2on the contrary, the increase in artificial wetland area was 144.37 km2.② Urban wetland landscape diversity decreased，evenness reduced，and dominance increased from 1987 to 2005. These changes reflect that urban wetland landscape types gradually tend to be assimilative.③ The fragmentation of reservoir and pond wetlands was the largest, which indicated that the impact of human activities was the biggest for the reservoir and pond wetlands.④ The centroids of river and lake wetlands moved southwest and the centroids of reservoir and pond wetlands moved southeast.⑤ The increasing warm and dry climate，the rapid population growth,and the rapid economic development as well as the rapid urbanization are major reasons for the structural changes in urban wetland landscape pattern from 1987 to 2005.关键词：urban wetlands;dynamic evolution;Remote Sensing（RS）;Geographic Information System (GIS);driving mechanism;landscape ecology
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发布时间：2023-12-11 - 摘要：The natural organic matter(NOM) in water may produce carcinogens in the chlorination process. It is necessary to find a highly efficient method of NOM removal. In this paper, the effects of hydraulic conditions, pH value and Al2(SO4)3dosage on coagulation are studied with the enhanced coagulation technology. The results show that the enhanced coagulation technology can remove NOM efficiently, while controlling the residual Aluminum within the standard. The TOC decreases quickly with increasing Al2(SO4)3dosage, but the removal rate remains stable when dosage is over 0.2 mmol/L. The residual Aluminum decreases with the rising of pH value until 8.0, and then increases. The TOC of residual organic matters is controlled at about 1.4 mg/L and residual aluminum is kept below 0.05 mg/L in water with pH value of 8.0 and Al2(SO4)3dosage of 0.3 mmol/L.关键词：enhanced coagulation;organic matter;residual aluminum
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发布时间：2023-12-11 - 摘要：As an important part of urban region structure, urban fringe is the most sensitive area with acute contradictions in modern urban system. Deeply research on the regulation of the regional spatial variation is very important for promoting urban construction and regional development. The method of multiple criteria was used to analyze the spatial evolution of the urban fringe in Guangzhou for 1990, 2000 and 2009. The result shows that: ① The development mode of Guangzhou has gradually changed from “single core” expansion to “point-axis’ expansion, and a metropolitan area with “multi-cores” will be eventually formed. ② At the beginning of 1990s, Guangzhou was in the process of urbanization accelerated phase, and the urbanization was extensive and disordered. Since 2000, the overall strategic development center has moved to the south of Guangzhou. ③ The urban expansion and fragmentation are of synchronization and similarity. the variation extent of degree of fragmentation can indicate the level of urbanization. ④ Urban fringe is a spatial-temporal complex, which is extremely sensitive and unstable. In the early stage of development, it is no-continuous and broken, and later it becomes continuous and compact. This phenomenon from disorder to order occurs throughout the development of the urban fringe. The result can provide theoretical support and reasonable proposals for strategic development plan and the integration of urban and rural construction.关键词：urban fringe;urban region structure;spatial evolution;Guangzhou
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发布时间：2023-12-11 - 摘要：Ethyl-hydroxyimino-bromopropanoate was prepared from ethyl lactate, NBS and hydroxylamine hydrochloride in a novel method. In the reaction process, intermediate ethyl bromopyruvate was obtained by bromination and oxidation, instead of being separated from the reaction mixture and directly used to react with hydroxylamine hydrochloride in CHCl3and CH3OH solution. The white crystal product was obtained in 48% yield. The new derivative ethyl-3-bromo-2-(1-naphthoyl-oximino) propanoate was synthesized successfullyviathe mild esterification reaction. The target compound was characterized by1HNMR13C-NMR and elemental analysis.关键词：ethyl bromopyruvate;ethyl hydroxyimino-bromopropanoate;synthesis
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发布时间：2023-12-11
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