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1.
Sticker model is one of the basic models in the DNA computer models. This model is coded with single-double stranded DNA molecules. It has the following advantages that the operations require no strands extension and use no enzymes; What‘s more, the materials are reusable.Therefore it arouses attention and interest of scientists in many fields. In this paper, we will systematically analyze the theories and applications of the model, summarize other scientists‘ contributions in this field, and propose our research results. This paper is the theoretical portion of the sticker model on DNA computer, which includes the introduction of the basic model of sticker computing. Firstly, we systematically introduce the basic theories of classic models about sticker computing; Secondly, we discuss the sticker system which is an abstract computing model based on the sticker model and formal languages; Finally, extend and perfect the model, and present two types of models that are more extensive in the applications and more perfect in the theory than the past models: one is the so-called k-bit sticker model, the other is full-message sticker DNA computing model.  相似文献   

2.
Newton’s law of gravity is a theory of instantaneous action at a distance.However,Einstein’s general relativity states that the speed of gravity equals the speed of light,which is finite.Therefore,it is a worthy problem to discuss if Newton’s law of gravity needs modification,when studying and observing the gravitational tidal.In this paper,it is shown that the Newton’s law of gravity is fully applicable in the framework of general relativity.Based on the post-Newtonian approximation,we find that the observable effect for the speed of gravity is irrelevant to the velocity of a moving source,but it is dependent on its acceleration.In general,the effect of the speed of gravity is so weak that today’s any astronomical observations,including the sun tidal observations,can not confirm that the gravitational field travels at the speed of light.  相似文献   

3.
陈凡 《科技信息》2012,(28):196-197
Graham Greene is one of the most important English writers in the 20th century.In Greene’s novels,readers easily find a literary world which is a dark land filled with violence,guilt,corruption and other forms of evil."The Destructors"also reflects this theme.Being interested in the story and the teenagers’growing-up,the author starts this paper-An Analysis of the theme and the characters in"The Destructors".First of all,this paper discusses the reasons that cause the gang to make destructions.The children are so violent;it has its intangible needs.It gives a new view to think about the children’s heart and makes us to recognize what the war left to people,especially to the children.And then,based on the analysis of the theme and characters,this paper discusses that the characters and their actions project the theme to a great extent,and that the teenagers’psychology and actions are greatly determined by their surroundings,which should be reconsidered by instructors.The moral and character education should gain a good deal of enlightenment from it.  相似文献   

4.
In every field of engineering, testing is a fundamental step for the validation of design, being the most direct way to verify that a product meets its specifications. If the desired performance is not achieved, testing should identify all the causes of malfunctioning and indicate suitable corrective actions. Different algorithms relying on the symbolic approach have been presented in the past by the authors and in this work noteworthy improvements on these algorithms are proposed. However, how the testability is designed to maintain devices during its lifetime is discussed lack at present. Furthermore, this problem concerns needing more times on testing and fault diagnosis, and wasting more manpower and material resources. Especially in the army devices field, it is very important that maintenance and indemnificatory are advanced. In this paper, the parameters in testability design for fault detection and diagnosis will be given. The detailed contents of testability will be proposed, including the dividing of circuit module in equipment, technology material needed for detection and requirement of specifications used for testing.  相似文献   

5.
In this paper we review a series of recent work on using a Fourier analysis technique to study the sta- bility and error estimates for the discontinuous Galerkin method and other related schemes. The advantage of this approach is that it can reveal instability of certain "bad"' schemes; it can verify stability for certain good schemes which are not easily amendable to standard finite element stability analysis techniques; it can provide quantitative error comparisons among different schemes; and it can be used to study superconvergence and time evolution of errors for the discontinuous Galerkin method. We will briefly describe this Fourier analysis technique, summarize its usage in stability and error estimates for various schemes, and indicate the advantages and disadvantages of this technique in comparison with other finite element techniques.  相似文献   

6.
Based on some experts‘ research effort, the problems of land subsidence and relative sea level rise in three Chinese delta areas(Huanghe, Changjiang and Zhujiang Delta) are analyzed and discussed in this paper. The authors‘ opinion is that the land subsidence is mainly induced by human activity and has made the greater contributions to the relative sea level rise and become one of the geological hazards in these areas. In Tianjin and Shanghai areas where had ever existed serious land subsidence problem, due to the positive and effective control methods, the ratio of man-induced land subsidence to relative sea level rise decreased from 80% - 90% in 1960s - 1970s to less than 60% at present. But it is estimated that in the next tens of years this ratio will still be considerable. So human being must keep its eyes on this phenomenon and take more positive countermeasures to control the land subsidenee.  相似文献   

7.
Lattice preferred orientations (LPO) of plagioclase and augite are measured on layered gabbro from the Panxi region, Sichuan Province. The LPO concentration [010] of plagioclase and [100] of augite are perpendicular to the foliation, which indicates a kind of growth fabric associated with crystallizing habits of minerals when the magma is solidifying under the compaction. Calculated seismic velocities based on LPO data of minerals give rise to rather strong anisotropy 5.81% and 5.54% for compressional seismic wave (Vp) and shear seismic wave (Vs), respectively. The experiments at high temperature and high pressure show that the P-wave velocity of layered gabbro is 6.4-6.97 km/s with the maximum Vp anisotropy 5.22% and the Poisson‘s ratio is between 0.28-0.31. According to the comparison of fabrics with seismic velocities of layered gabbro, it is suggested that the large-scale layered intrusive body or the similar layered geological body may exist in the lower crust of this area. Such a layered intrusive body which has strong seismic anisotropy may be the seismic reflector in the lower crust.  相似文献   

8.
Sutong Bridge tower which is 300.4 m is the highest one in the world. The tower anchor area uses the steelconcrete composite structure, its structure and the stress mechanism are complex, so it must be paid more attention to the structure durable issue. The 300 m height makes the tower quite sensitive to the environmental factors such as wind and temperature. The wind resistance safety of tower in construction stage is especially important. In this paper, the design of composite structure is introduced. The key technologies of tower geometry control and wind resistance in construction stage are analyzed.  相似文献   

9.
Moldability evaluation for molded parts,which is the basis of concurrent design,is a key design stage in injection molding design.By moldability evaluation the design problems can be found timely and an optimum plastic part design achieved.In this paper,a systematic methodology for moldability evaluation based on fuzzy logic is proposed.Firstly,fuzzy set modeling for six key design attributes of molded parts is carried out respectively.Secondly,on the basis of this,the relationship between fuzzy sets for design attributes and fuzzy sets for moldability is established by fuzzy rules that are based on domain experts‘ experience and knowledge.At last the integral moldability for molded parts is obtained through fuzzy reasoning.The neural network based fuzzy reasoning approach presented in this paper can improve fuzzy reasoning efficiency greatly,especially for system having a large number of rules and complicated membership functions.An example for moldability evaluation is given to show the feasibility of this proposed methodology.  相似文献   

10.
This paper proposes a steady-state errors correction (SSEC) method for eliminating measurement errors.This method is based on the detections of error signal E(s) and output C(s) which generate an expected output R (s).In comparison with the conventional solutions which are based on detecting the expected output R (s) and output C (s) to obtain error signal E (s),the measurement errors are eliminated even the error might be at a significant level.Moreover,it is possible that the individual debugging by regulating the coefficient K for every member of the multiple objectives achieves the optimization of the open loop gain.Therefore,this simple method can be applied to the weak coupling and multiple objectives system,which is usually controlled by complex controller.The principle of eliminating measurement errors is derived analytically,and the advantages comparing with the conventional solutions are depicted.Based on the SSEC method analysis,an application of this method for an active power filter (APF) is investigated and the effectiveness and viability of the scheme are demonstrated through the simulation and experimental verifications.  相似文献   

11.
Hardware/software(HW/SW) partitioning is one of the key processes in an embedded system.It is used to determine which system components are assigned to hardware and which are processed by software.In contrast with previous research that focuses on developing efficient heuristic,we focus on the pre-process of the task graph before the HW/SW partitioning in this paper,that is,enumerating all the sub-graphs that meet the requirements.Experimental results showed that the original graph can be reduced to 67% in the worst-case scenario and 58% in the best-case scenario.In conclusion,the reduced task graph saved hardware area while improving partitioning speed and accuracy.  相似文献   

12.
徐凤娇 《科技信息》2009,(20):I0081-I0082
Hugh MacLennan is a famous Canadian novelist and essayist. In his long literary career, he wrote a great number of works and gained many literary honors. But above all, he is a writer, focusing on national issues of Canada, which is well demonstrated by his first novel-Barometer Rising, in which nationalism abounds. This paper covers three parts. Chapter one is mainly about Hugh MacLennan, his first work Barometer RAsing as well as the introduction to nationalism and MacLennan's contribution in fiction in this respect. Chapter two focuses on nationalism in his first novel. The last chapter is the conclusion part in which we know that well awakened, the Canadians are striving to pursue their real independence and stares on the international stage.  相似文献   

13.
History of uranium exploration and the general situation of identified uranium resources in China are introduced briefly in the paper, and the feature of uranium resources is summarized as “a large number of deposits, good ore processing properties and centralized occurrence” which should be considered as the advantages. In accordance with the fact that the exploration level of uranium resources is quite low in China, it is pointed out that exploration investment must be intensified from now on to identify more uranium concentrated bases which occurring of middle to large size uranium deposit in order to meet the demand of natural uranium from nuclear power sector. Besides, major scientific and technological achievements on uranium exploration during the past fifty years are elaborated in the paper. According to the exploration ability and uranium resources potential in China, it is believed that uranium exploration can realize the goal of “getting break through both at home and abroad” and meet the requirement of nuclear industry to uranium resources in China by carrying out the uranium resources exploration strategy of “rooted in domestic and opening up abroad”.  相似文献   

14.
Currently, some commercial software applications support users to work in an integrated environment. However, this is limited to the suite of models provided by the software vendor and consequently it forces all the parties to use the same software. In contrast, the research described in this paper investigates ways of using standard software applications, which may be specialized for different professional domains. These are linked for effective transfer of information and a binding mechanism is provided to support consistency. The proposed solution was implemented using a CAD application and an independent finite element application in order to verify the theoretical aspects of this work.  相似文献   

15.
Internal grinding is more difficult than surface grinding and cylindrical grinding. But littleresearch work in this field has been done. In this paper, based on a series of investigations, in-ternal grinding with vitrified bond CBN wheels was proposed. The method is considered mostsuitable for grinding ball-bearing parts in mass production as well as for CNC grinder. Thetheoretical analyses or internal grinding are also given, and a large number of textile machineparts-shell roller(the material is bearing steel GCr15) were grinded using Cr-corundumwheels and cubic boron nitride(CBN) wheels. Experiments indicated that grinding with CBNwheels had technical and economical advantages, and it might be used in a wider range.  相似文献   

16.
Taking lapels as examples,the purpose of this paper is to study the problem of recognizing the same clothing component in the flat sketches. Supposing that the four lines in a lapel are concurrent and symmetrical,a mathematical lapel model is built. Then,a novel method for lapel recognition in fashion flat sketches based on the lapel model is proposed. In the image preprocessing stage, the images need to be cropped for two times in order to remove the blank background and extract the region of interest,respectively. In the concurrent recognition stage,line detection,θ selection,and curve fitting are applied to limiting candidate lines. In the symmetrical recognition stage, k-means clustering algorithm is employed to divide the selected lines into four clusters. The threshold values of the difference of corresponding weighted θ are set as lapel recognition criteria. Experiments demonstrate that the recognition accuracy of the proposed method is obtained at about 91. 7%.  相似文献   

17.
Four methods for testing the thickness and defect of pipeline are compared and analyzed in this paper. The testing principle of magnetic leakage flux based on electromagnetism is discussed in detail. From the experiments of sensor character, the effects caused by some factors are found, which give some important information for sensor design, and this method is proved reasonable and effective. The mechanical and electrical structures of inspection equipment, as well as its working principle and technical features are introduced. In this paper, control flow and software design are discussed, too. This detection system has been successfully developed. Experiments show that this detection system has high resolution and can be put into practice.  相似文献   

18.
赵明  丁巨刚 《科技信息》2007,(1):152-154
This paper mainly focuses on the respective character of the main protagonists in the novel Jane Eyre.First of all,this paper analyses Jane Eyre's personality which account for her plain appearance-being true,being benevolent and generous.And it follows the moral growth of Jane Eyre.Secondly it explores Rochester's unusual background and past,which causes both Jane and his physical and spiritual torment.Moreover,the paper analyses John,Jane's cousin,who has adampening,frigid influence on Jane's passionate nature.In addition,it attaches great importance to the symbolism of the air and names in the novel.By contrast of the protagonists and their respective ending,the paper tells that the best policy for women or the whole human beings is to be independent and equal,which is fated to vanquish all evils and difficulties.  相似文献   

19.
In the areas of China access into WTO Agreements, Chinese government has made lots of promises in reducing tariffs of some industrial products. While industrial products make up a very large share of import and export, so nearly all kinds of them will be influenced, especially those which are protected by means of national tariffs and taxes and non- tariffs barriers on import-sand, to a lesser extent, on exports. Meanwhile we have noticed that most of these industries are the pillar ones of Yangtze Delta. As it is well known that Yangtze Delta has become the most developed area in Yangtze valley or even in China and had an important effect on China economy. Thus entry to the WTO requires reform to be accelerated in this district so as to put the industry of this region in a position to be able to cope with the greater foreign competition that will follow accession to the trade body.  相似文献   

20.
The structure of Web site became more complex than before. During the design period of a Web site, the lack of model and method results in improper Web structure,which depend on the designer‘s experience. From the point of view of software engineering, every period in the software life must be evaluated before starting the next period‘s work. It is very important and essential to search relevant methods for evaluating Web structure before the site is completed. In this work, after studying the related work about the Web structure mining and analyzing the major structure mining methods (Page-rank and Hub/Authority), a method based on the Page-rank for Web structure evaluation in design stage is proposed. A Web structure modeling language WSML is designed, and the implement strategies for evaluating system of the Web site structure are given out. Web structure mining has being used mainly in search engines before. It is the first time to employ the Web structure mining technology to evaluate a Web structure in the design period of a Web site. It contributes to the formalization of the design documents for Web site and the improving of software engineering for large scale Web site, and the evaluating system is a practical tool for Web site construction.  相似文献   

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