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1.
Myrtama is a genus named from Myricaria elegans Royle in the 1970's in terms of its morphological peculiarities. The establishment of this genus and its systematic position have been disputed since its inception. ITS sequences from 10 species of Tamaricaceae are reported, and analyzed by PAUP 4.0b8 and Bayesian Inference to reconstruct the phylogenies. A single ITS tree is generated from maximum parsimony and MrBayes analyses, respectively. The molecular data set shows strong support for Tamarix and Myricaria as monophyletic genera, and Myrtama as a sister group to the genus Myricaria. Based on morphological differences, a single morphological tree is also generated, in which two major lineages existed but Myrtama is a sister group to Tamarix, rather than Myricaria. The evidence from DNA sequences and morphological characters supports that Myicaria elegans should be put into neither Myricaria nor Tamarix, but kept in its own monotypic genus.  相似文献   

2.
The Absorption and permeability of air-jet textured glass fiber yarn and its fabric and bonded tenacity of the fabric have been studied in relation to the main parameters, air supplied pressure and overfeed ratio. It has been observed that increasing the level of main parameters improves the coated ratio of the textured yarn and its fabric as well as the bonded tenacity of the fabric made of textured yarn. Comparison of absorption or permeability between textured and supplied yarns, and comparison of absorption or permeability and bonded tenacity between the two kinds of fabrics have been elucidated.  相似文献   

3.
Role of ran GTPase in cell cycle regulation   总被引:1,自引:0,他引:1  
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4.
Three kinds of specimens were produced from hot strips of similar composition and same thickness (nominal gauge 4.0 mm) but produced using different technologies, and the dislocation density of these strips was quantitatively measured by positron annihila- tion technique test. The dislocation morphology and evolution in microstructure of each pass for producing the 1.9 mm hot strip using CSP (compact strip production) technology were observed under an H-800 transmission electron microscope; its density was also quantitatively measured using the positron annihilation technique test, and the factors influencing the dislocation density during the production process were analyzed. The experimental results show that the dislocation density in the microstructure produced using CSP technology is higher than that in the microstructure produced using conventional technology. This result was discussed and confirmed on the basis of the finite element simulation and the theory relevant to dislocations.  相似文献   

5.
Three kinds of specimens were produced from hot strips of similar composition and same thickness (nominal gauge 4.0 mm) but produced using different technologies, and the dislocation density of these strips was quantitatively measured by positron annihilation technique test. The dislocation morphology and evolution in microstructure of each pass for producing the 1.9 mm hot strip using CSP (compact strip production) technology were observed under an H-800 transmission electron microscope; its density was also quantitatively measured using the positron annihilation technique test, and the factors influencing the dislocation density during the production process were analyzed. The experimental results show that the dislocation density in the microstructure produced using CSP technology is higher than that in the microstructure produced using conventional technology. This result was discussed and confirmed on the basis of the finite element simulation and the theory relevant to dislocations.  相似文献   

6.
The Yuanmou Basin of Yunnan Province is a hotspot for the research of early homind evolution and its environmental background.During the implementation of the Program“Research of the Origin and Evolution of Early Man and Its Environmental Baqckground” from 1998 to 2001,a huge quantity of hominoid and mammal fossils were collected.The present report systematically describes an Euprox robustus sp.nov.identified during the recent laboratory work on the collected material.Euprox is a group of earliest cervids with true antlers.The new species is the third one of the genus discovered in China.Judged by its morphologic characteristics,the new species feed on juicy and tender leaves of dicotyledon.It implies that the vegetation of its epoch in the Yuanmou Basin is a kind of southern subtropical evergreen forest and the climate is humid and temperate with evident seasonality.The latter is mostly influenced by the monsoon and secondly by the latitude.  相似文献   

7.
English news serves as a way to widen one's knowledge of international community and plays a significant part in our daily life.It distinguishes itself from other styles of writing by its special stylistic characteristics in its headline and its body on the grammar level,on the lexical level and on the rhetorical level.Mastering them can be beneficial to our comprehension of English news and further study,hence helps us obtain news information more quickly and makes us keep pace with the constant change of the new time.  相似文献   

8.
The developing process of simulation technology is discussed in view of its development, maturation and further development.The applications of simulation technology in the fields of national economy are introduced. Finally, the level and status quo of simulation technology home and overseas are analyzed, and its future trend in the new century is presented.  相似文献   

9.
Based on the tests of eight kinds of typical fabrics, the relation between the drape coefficient of different fabrics and its revolving speed was analyzed and discussed. The result of regression curve fitting of experimental data showed that the relation between drape coefficient of fabric and its revolving speed could be expressed by negative exponential equation. Meanwhile, the difference of drape coefficients between static and dynamic at 100 - ISOr.p.m was suggested to be one of the expressing parameters of the lively degree of fabric dynamic drape.  相似文献   

10.
Based on an example of its typical structure, the concept of modular fixture structure module is presented, and the structure module system of modular fixture is summarized. Then the parametric design of structure is discussed, and its advantages are also emphasized. Furthermore, some specific methods are provided, such as the selection of fixture components, the determination and input of parameters, drawing representative model, and the creation of drawing. Finally an applied example of structure parametric design is presented.  相似文献   

11.
Early tectonic uplift of the northern Tibetan Plateau   总被引:6,自引:0,他引:6  
The Hexi Corridor is the northmost foreland basin of the Tibetan Plateau and its formation is controlled by the northern marginal fault of Tibet, Altyn Tagh Fault (ATF)-North Qilian Shan marginal Fault (NQF), and the southern Kuantan Shan-Longshou Shan Fault (KLF). So its study is important to understanding the mechanism of Tibet formation and its influence on global climate change. The oldest Cenozoic sediments in the Corridor is the Huoshaogou Formation which consists of terrigenous fine conglomerate, sandstone, sandy mudstone and mudstone, depositing in al- luvial to lacustrine and fan delta sedimentary environments. Detailed paleomagnetic measurements of this sequence at Yumen clearly reveal eleven pairs of normal and reversed polarities. Fossil mammals found around the section support that most of the observed polarities can be well correlated with chrons between 13n and 18r of the standard geomagnetic polarity time scale, yielding ages of 40.2-33.35 Ma. The mean declinations of this sequence and its immediately above stratigraphy indicate an 18.3° rapid clockwise rotation of the Hexi Corridor. Since this sequence has been strongly folded and is capped by an angular unconformity, we think that the presence of the thick alluvial fan conglomeration at the bottom of the foreland basin may indicate the initial deformation and uplift of the northern Qilian Shan. This process could occur at latest at 40.2 Ma, driven by the faults NQF and KLF that thrust onto the Hexi corridor respectively from its southern and northern margins. These faults are in an early response to the collision of India with Asia, while the unconformable termination and rotation of the Huoshaogou Formation at -33.35 Ma indicate other early episode of rapid tectonic deformation and uplift of the northern Tibet.  相似文献   

12.
The probability density function of irradiance fluctuations in a turbulent atmosphere remains an open topic of research.It is generally considered that the speckle field has an elliptical-Gaussian speckle distribution,but because of its complexity there is still no exact analytical solution.By introducing the concept of random fluctuation intensity and using an equiprobability density ellipse,exact models of the random fluctuation intensity and its phase are proposed.Through theoretical analysis and numerical simulation,it is concluded that the random fluctuation intensity and its corresponding phase are independent only under the circular-Gaussian approximation.  相似文献   

13.
This paper firstly gives a brief introduction about the discourse analysis and its importance, and then focuses on the analysis of an scientific article by use of the problem-solution pattern and lexical signalling. At last, the analysis is applied to the language teaching in reading and writing which assures its importance.  相似文献   

14.
15.
盛美兰 《科技信息》2009,(34):I0137-I0138
As one indispensable part of the twentieth century western literary criticisms,Feminist Criticism has shown its charming feature and affected the world greatly.This paper briefly introduces the past,present and future of Feminist Criticism in China,showing that the research and application of it will have its bright future.  相似文献   

16.
Bioremediation: A review of applications and problems to be resolved   总被引:9,自引:0,他引:9  
This review article describes the factors affecting bioremediation processes including: goals of bioremediation and the optimal ecological conditions required; inoculation of microorganisms; co?metabolism; bioavailability and its improvement; biological evolution and its utilization;monitoring and control of bioremediation processes; identification of bioremediation effectiveness and ecological remediation and its key elements. The current progress in bioremediation techniques is summarized. The direction of future development, research and applications is also examined.  相似文献   

17.
IPX is one of most widely used protocol of datagram in LAN. It will have the great significance and find its wide use to design a poiverful Electronic Mail System (EMAIL) on IPX protocol. This paper analyzes the access interface of the IPX protocol at first,then accounts for the design thought of the LAN Electronic Mail System and. the design of its upper jour layers protocols and software on emphasis.  相似文献   

18.
Photosensitized splitting of cis-syn 1,3-dimethyluracil dimer by tryptophan (Trp) and its peptides (Trp-Tyr and Trp-Phe) is studied by fluorescence quenching experiments and irradiation experiments.It reveals that 1,3-dimethyluracil dimer is mainly split by e?-?aq resulting from two-photon ionization of Trp and its peptides under irradiation with light (λ>290 nm).Moreover,the excited singlet state of Trp and its peptides can transfer an electron to the dimer,which splits and gives two pyrimidines.In addition,because of its lower oxidative potential,the excited triplet state of Trp-Tyr can also split the dimer via transfering an electron to the dimer.  相似文献   

19.
Firstly data standardization technology and combined classification method have been applied to carry out classification of kinematic behaviors and mechanisms in the mapping field between the kinematic behavior level and the mechanism level of conceptual design. The principle of computer coding and storing have been built to give a fast and broad selection of mechanisms that meets the requirements of basic motion characters. Then on the basis of mentioned above, the heuristic matching propagation principle (HMPP) of kinematic behaviors and its true table serves as a guide to perform mechanism types selection. Finally an application is given to indicate its practicability and effectiveness.  相似文献   

20.
This paper aims to observe euphemisms and its translation from cultural point of view.As euphemisms are,more often than not,the reflection of a certain culture,it is advisable to take into consideration their cultural connotation in understanding and translating euphemisms.And the thesis itself is probe into the translation methods and skills of euphemisms,via the origination of euphemism and the analysis of the relationship between euphemisms and culture to reflect its cultural connotation as far as possible.  相似文献   

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