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1.
It is proposed that local and transient reconnection in the plasma boundary layer can be caused by the impact and switch-off of non-homogenous dynamic pressure. Magnetohydrodynamic simulation is used to investigate the reconnection processes in these two cases. It is found that if the inflow is homogeneous, the reconnection will not take place; if the inflow is a shearing flow, no matter how great the shear of the flow is, the reconnection can be caused either during or after the impacting period. It is pointed out that a sudden stop of external force may be an important triggering mechanism of energy transformation and reconnection in the plasma boundary layer region.  相似文献   

2.
邢华 《科技信息》2012,(22):164-165
As we know when we do translation we must know the meaning of every word or phrase first and then translate them.But translation is not as simple as just translate English into Chinese or Chinese into English,and we couldn't know the exact meaning until we consider those words,phrases or even sentences in a specific context.Now you may be eager to know the relationship between translation and context and what context is.So in this paper I will make a brief introduction about it.In this paper I classify context into two groups: context of situation and context of culture.Then I will give a detailed introduction about the influences of context on translating.The English translator and theorist Peter Newmark had said:"a common mistake is to ignore context.A not uncommon mistake is to make context the excuse for inaccurate translation".In the last chapter I will discuss the function of context in translation,how to find useful information from context and make it serve for translating better.  相似文献   

3.
In modern times,many students think English grammar is complex and boring,they learn it just for getting higher scores in English examination.Also most of the English teachers use the traditional teaching method to teach the students and let them control the grammar points rigidly,which makes the students feel the grammar is more difficult and complex.Chinese teachers and students tend to put emphasis on explicit curriculum.Teacher’s teaching methods and how the students to study grammar and other factors all restrict the development of hidden curriculum.In fact it can be mastered easily if we combine it with the exploration of hidden curriculum.By this way they can become fond of it little by little and they can find that their ability is greatly improved,they can benefit a lot in every aspect at last.Here I will state it in details about how to explore the hidden curriculum through English grammar teaching.  相似文献   

4.
The GaAs material is a major semiconductor material, and it has high electron transfer rate and direct transition energy band structure. The devices and inte-grated circuits fabricated on the GaAs substrates have a lot of advantages such as high speed information processing. Small perturbations in the manufacturing of GaAs materi-als can lead to defects. The defects in the GaAs materials can degrade the performance of materials. A new method is presented in this paper for detecting the micro-defects in GaAs materials by using time resolved emissions. In this method, the micro-defects in GaAs materials are detected by making use of the photon emission features of micro- defects. The strength of the emitted photons from the micro-defects is increased by applying the electric current or the periodic pulse signals to GaAs materials. The single-photon detector is used to detect the photon emissions of the micro-defects. The time resolved photon emissions and single-photon detection are used to record and compare the amounts of the emitted photons that come from the given regions of the normal GaAs materials and the defective GaAs materials. A lot of experimental results show that the micro-defects in the GaAs materials can be detected by using the method proposed in this paper.  相似文献   

5.
Our previous studies demonstrated that JWA,a novel retinoic acids responsive and cytoskeleton related gene, is associated with cell differentiation and apoptosis. In the present study, to elucidate if the JWA is a novel kind of microtubnle-associated proteins (MAPs) and functiona llylink to microtubule, we first successfully identified JWA from the physically purified MAPs complex of rat braint issues. The results of co-immunoprecipitation, gene transfection and immunofluorescence microscopy assays from HBE and NIH3T3 cells provide strong evidence for a linkage between JWA and β-tubulin. In general, JWA is stably binding to β-tubulin whenever microtubule is polymerized or not,and it may be critical to the mitosis process. In addition, by use of the antisense oligonucleotides technique, we also showed that JWA is a negative modulator on intracellular amino acids in PC12 cells. Further analysis indicated that JWA selectively regulates both taurine, an inhibitory aminoacid, and glutamate, an excitatory amino acid. In conclusion,JWA is not only structurally associated, but also a novel functional MAP.  相似文献   

6.
A ring R is called a GVNL-ring if a or 1-a is π-regular for every a∈R,as a common generalization of local and π-regular rings.It is proved that if R is a GVNL ring,then either(1-e)R(1-e) or eRe is a π-regular ring for every idempotent e of R.We prove that the center of a GVNL ring is also GVNL and every abelian GVNL ring is SGVNL.The formal power series ring R[x] is GVNL if and only if R is a local ring.  相似文献   

7.
The focus of almost all the association studies of candidate genes is to test for their importance. We recently developed a LOD score approach that can be used to test against the importance of candidate genes for complex diseases and quantitative traits in random samples. As a complementary method to regular association analyses, our LOD score approach is powerful but still affected by the population admixture, though it is more conservative. To control the confounding effect of population heterogeneity, we develop here a LOD score exclusion analysis using case?parents design, the basic design of the transmission disequilibrium test (TDT) approach that is immune to population admixture. In the analysis, specific genetic effects and inheritance models at candidate genes can be analyzed and if a LOD score is ≤-2.0, the locus can be excluded from having an effect larger than that specified. Simulations show that this approach has reasonable power to exclude a candidate gene having small genetic effects if it is not a disease susceptibility locus (DSL) with sample size often employed in TDT studies. Similar to association analyses with the TDT in nuclear families, our exclusion analyses are generally not affected by population admixture. The exclusion analyses may be implemented to rule out candidate genes with no or minor genetic effects as supplemental analyses for the TDT. The utility of the approach is illustrated with an application to test the importance of vitamin D receptor (VDR) gene underlying the differential risk to osteoporosis.  相似文献   

8.
In view of the fact that complex signals are often used in the digital processing of certain systems such as digital communication and radar systems,a new complex Duffing equation is proposed.In addition,the dynamical behaviors are analyzed.By calculating the maximal Lyapunov exponent and power spectrum,we prove that the proposed complex differential equation has a chaotic solution or a large-scale periodic one depending on different parameters.Based on the proposed equation,we present a complex chaotic oscillator detection system of the Duffing type.Such a dynamic system is sensitive to the initial conditions and highly immune to complex white Gaussian noise,so it can be used to detect a weak complex signal against a background of strong noise.Results of the Monte-Carlo simulation show that the proposed detection system can effectively detect complex single frequency signals and linear frequency modulation signals with a guaranteed low false alarm rate.  相似文献   

9.
10.
The electromagnetic field energy distribution inside the left-handed metamaterials (LHMs) with or without blank and line defects is firstly investigated. The LHMs consist of an array of periodic unit cells of copper hexagon split ring resonators (SRRs) and wires. The internal energy distribution of the LHMs is measured in a microwave measuring line device at X-band frequencies. It is found that the LHMs only respond to the electromagnetic field around the resonance frequency. The electromagnetic field amplitude inside the LHMs generally decreases with the introduction of defects. It is suggested that the electromagnetic field energy reduction may arise from the symmetry breaking in the LHMs.  相似文献   

11.
Miao  Laicheng  Fan  Weiming  Zhang  Fuqing  Liu  Dunyi  Jian  Ping  Shi  Guanghai  Tao  Hua  Shi  Yuruo 《科学通报(英文版)》2004,49(2):201-209
Located in the eastern portion of the Xing'an-Mongolian Orogenic Belt (XMOB), the Xinkailing-Kele complex has previously been considered to be Precambrian metamorphic rocks, mainly according to its relatively high metamorphic grade. Our filed observation, however, revealed that the complex is composed mainly of metamorphic rocks (Kele complex), tectono-schists ("Xinkailing Group"), and granitoids (Xinkailing granitic complex). Dating on these rocks using advanced SHRIMP zircon U-Pb technique indicates that: (1) Biotite-plagioclase gneiss from the Kele complex has a protolith age of 337±7 Ma (2σ) and a metamorphic age of 216±3 Ma (2σ); (2) the tectono-schist of the "Xinkailing Group" gave a magmatic age of 292±6 Ma (2σ), indicative of felsic volcanic protolith of the schist formed in late Paleozoic time; and (3) the Menluhedingzi and Lengchuan granites of the Xinkailing granitic complex were emplaced at 167±4 (2σ) and 164±4 Ma (2σ), respectively. These results suggest that the Xinkailing-Kele complex is not Precambrian metamorphic rocks and the so-called Precambrian "Nenji-ang Block" does essentially not exist. In combination with regional geological data, we propose that the Kele metamorphic complex is likely related to a collisional tectonism that took place in Triassic time, as indicted by its metamorphic age of 216±3 Ma. The Xinkailing granitic complex was em-placed along the collisional zone during Mid-Jurassic time, likely in a post-orogenic or anorogenic setting.  相似文献   

12.
An H-covering(resp.decomposition) of a graph G is a set of subgraphs of G,{H_1,H_2,…,H_k} such that H_1 is isomorphic to H for eachi,and each edge of G belongs to at least(resp.exactly) one of the subgraphs H_i,fox 1≤i≤k.An H-covering(resp.decomposition) of a graph G is a magic H-covering(resp.decomposition) if there is a bijection f:V(G)∪E(G)→{1,...,|V(G)|+|E(G)|} such that the sum of labels of edges and the vertices of each copy of H in the decomposition is a constant.If G admits a unique H-covering H and H is a magic H-covering of G,then G is H-magic.In this paper,we show that if G admits a magic H-covering(resp.decomposition),and satisfies some other conditions,then a union of k vertex joint graph G,kG,and a graph obtained from kG,Gk admit a magic H-covering or decomposition.  相似文献   

13.
Evolutionary changes in the structure of leaves have had far-reaching effects on the anatomy and physiology of vascular plants, resulting in morphological diversity and species expansion. People have long been interested in the question of the nature of the morphology of early leaves and how they were attained. At least five lineages of euphyllophytes can be recognized among the Early Devonian fossil plants (Pragian age, ca. 410 Ma ago) of South China. Their different leaf precursors or "branch-leaf complexes" are believed to foreshadow true megaphylls with different venation patterns and configurations, indicating that multiple origins of megaphylls had occurred by the Early Devonian, much earlier than has previously been recognized. In addition to megaphylls in euphyllophytes, the laminate leaf-like appendages (sporophylls or bracts) occurred independently in several distantly related Early Devonian plant lineages, probably as a response to ecological factors such as high atmospheric CO 2 concentrations. This is a typical example of convergent evolution in early plants.  相似文献   

14.
15.
Let H be finite dimensinonal Hopf algebra over a field and A an H-module algebra.The H induces an action on the CA#H(A) by adjoint and CA#H(A)^H=Z(A#H)=C,where CA#H(A) denotes the centralizer which algebra A in A#H and Z(A#H)the center of A#H.The aim of this paper is to discuss,the Galois conditions on the centralizer CA#H(A).We prove that CA#H(A)/ZA#H is H^*-Galois if and only if CA#H(A)#H/CA#H(A) is H-separable).Furthermore,if H is a finite dimensional semisimple Hopf algebra and CA#H(A)#H is an Azumaya C-algebra or A#H/A is H-separable,CA#H(A)statisfies the double centralizer property in CA#H(A) H,CA#H(A)?C is separable and there exists a cocommutative left integral t∈∫^1 H,then CA#H(A)/C is H^*-Galois.  相似文献   

16.
This paper introduces a non-assembly manufacturing case with microstereolithography technology. The design and manufacturing process of a pneumatic thrust bearing is described, and a special tessellation method is developed to further improve the capability of the manufacturing system thus bigger products can also be easily manufactured. Implemented in a layer-by-layer fashion, stereolithography has been used for the rapid manufacturing of complex devices, and it avoids the expensive assembly process in the traditional manufacturing. This paper presents that microstereolithography can produce high-resolution products with intricate details, small openings, and smooth surfaces. The potential of the microstereolithograhy technique is explored for the rapid manufacturing of small and complex objects.  相似文献   

17.
Ren Yongdong 《科技信息》2007,(15):368-370
1. Introduction Interest, which is one of the important forces that guidestudents’action and performance, is undoubtedly considered asthe best teacher. It is widely believed that if a student isinterested in one course, he will be so eager and does hisutmost to learn it, and learn it well, no matter how manydifficulties he is encountering. On the contrary, if he lacksinterest in it, he may never have great success in study. Thisindicates that interest is one’s conscious tendency to explorin…  相似文献   

18.
A light-harvesting chlorophyll a/b-protein complex (LHCP) was isolated directly from thylakoid membranes of marine green alga, Bryopsis corticulans, by two consecutive runs of liquid chromatography. The trimeric form of the light-harvesting complex has been obtained by sucrose gradient ultracentrifugation. The result of SDSPAGE shows that the light-harvesting complex is composed of at least five apoproteins in which a protein with apparent molecular weight of about 31 kD was never found in the major light-harvesting complex (LHC II ) from higher plants. The isolated Bryopsis corticulans light-harvesting complex contains a specific carotenoid, siphonaxanthin, as well as chlorophyll (Chl) a, Chl b, neoxanthin and violaxanthin. Siphonaxanthin which is present in the light-harvesting siphonaxanthin-chlorophyll a/b-protein complex of Bryopsis corticulans is responsible for enhanced absorption in the blue-green region (530 nm). Efficient energy transfer from both siphonaxanthin and Chl b to Chl a in Bryopsis corticulans LHCP, which has similar absorption and fluorescence emission spectra to those of the lutein-chlorophyll a/b-protein of higher plants, proved that molecular arrangement of the light-harvesting pigments was highly ordered in the Bryopsis corticulans LHCP. The siphonaxanthin-chlorophyll a/b-proteins allow enhanced absorption of blue-green light, the predominant light available in deep ocean waters or shaded subtidal marine habitats.  相似文献   

19.
20.
The characterization of non-stationary signal requires joint time and frequency information. However, time and frequency are a pair of non-commuting variables that cannot constitute a joint probability density in the time-frequency plane. The time-frequency distributions have difficult interpretation problems arising from negative and complex values or spurious components. In this paper, we get time-frequency information from the marginal distributions in rotated directions in the time-frequency plane. The rigorous probability interpretation of the marginal distributions is without any ambiguities. This time-frequency transformation is similar to the computerized axial tomography (CT or CAT) and is applied to signal analysis and signal detection and reveals a lot of advantages especially in the signal detection of the low signal/noise (S/N).  相似文献   

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