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果树2n配子研究进展 总被引：1，自引：0，他引：1
植物在进化过程中能产生低频率的未减数分裂配子,即2n配子,它在果树育种方面发挥着重要的作用。本文详述了2n配子的主要研究概况、发生途径及影响因素,为其在植物育种、种质利用和种质创新等方面提供了重要的应用基础。同时,通过近年的研究成果,总结出诱导方法和人工分离纯化方法,不同品种可根据其不同的生理生化特性选择合适的方法。另外,也叙述了2n配子在果树方面的特殊应用潜力,即在有性多倍化、稳定传递杂合性、克服自交不亲和和克服胚乳平衡数障碍方面有其他育种方法无法比拟的优势。因此,2n配子育种将会是一种重要的育种途径。 相似文献
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ZHANG Zhi-liao 《保鲜与加工》2005,(8):149-153
Migration for the reason of zoological environment is the measure for solving the crisis of zoological environment. Nowadays, governments play the chief role in the Migration for the reason of zoological environment, but the migration themselves do not have the freedom to decide whether migrate or not. Because the activity of migration is related to the restraint of economy, culture, law, etc. It is the object of migration that protect the zoological environment and improve the welfare of habitant, which must be concerned when constructing the systems of migration. This paper proves the possibility of contracting for migration based on the methodology of the cost-income analysis. On the other hand, it also argues for changing the mode of migration from that controlled by governments to being decided by habitant themselves. 相似文献
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彩色马蹄莲2n配子育种技术初探 总被引：2，自引：0，他引：2
以彩色马蹄莲的栽培品种‘黒魔术’Black magic、‘火烈鸟’Flamingo为实验材料,研究彩色马蹄莲2n配子育种技术。选择刚从茎秆中抽出的幼小健壮小花,用0.15%的秋水仙素处理以诱导2n配子,将诱导的2n配子进行不同组合的杂交实验。结果表明：秋水仙素处理对彩色马蹄莲雄雌蕊发育有一定毒副作用,其中对雌蕊的损伤大于雄蕊;2n配子能在一定程度上克服杂交后代不育性;在相同条件下,经2n配子诱导处理的杂交种子与未处理的对照种子相比,种子萌发时间大幅度缩短（50天左右）,叶片变薄、变大、叶色变浅,有些杂交植株表现出不同程度的畸变。通过对杂交后代的细胞学鉴定表明：处理配子杂交后代中获得染色体数目为48（2n=3x=48）的三倍体植株。 相似文献
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In the study on finding a group of inital values for solving operator equation x=G(x)by the two-sided iterative method,some stronger conditions forG(x)have been demandedand some new parameters have to be introduced since 1978,But,as it will be proved in this paper,Itis unnecessary to use any new parameters and other stronger conditions to get a group of initial val-ues of two-sided iterative, as those initial values can be obtained by means of an auxiliary iterativebeginning with operator G(x)itself. The numerical example in this paper illustraves that the methodproposed in this paper is a general method. 相似文献
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In the ironmaking process, it is essential that sinter and feed of blast furnace are established economically and reasonably. Taking some steel company for example, the best economical condition for feed of blast furnace is comprehensively considered from technologic demand and economic efficiency. According to LP and based on practice and trial, aimed function and confined condition is confirmed, computation programs are made by Matlab while realizing optimization feed. The blast furnace material balance and heat balance are calculated by program with visual interface. Thus, we can directly judge rationality of optimization. The results show that LP is effective method to realize feed of blast furnace. 相似文献
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This paper presents the sufficient condition for a square matrix of order n to the twofold magic square,with which the twofold magic square of order 64 is constructed.It is tested by the computer. 相似文献
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In high-rate digital mobile burst communication, it is important to acquire the symbol timing and carrier phase offset rapidly. This paper presents an algorithm of symbol timing and carrier phase offset acquisition for OQPSK. Proposed algorithm is parallel and has advantages over serial system that recover the carrier phase offset, and then estimate the symbol timing. This algorithm is easy to realize by using digital technology. 相似文献
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2n配子在大白菜育种上的应用 总被引：8，自引：0，他引：8
对二倍体大白菜的８７个自交系和３个杂交一代材料进行了雌雄２ｎ配子的测定。结果有１２个材料含有２ｎ配子，占总数的１３．３％。其中有５份既含雄性２ｎ配子又含雌性２ｎ配子，占５．６％。用５个不同包球类型并含有２ｎ配子的二倍体大白菜与四倍体大白菜杂交，选育出具有不同熟性，抗逆性强（抗多种病害，抗寒，耐热）、品质优良，口感好，营养成份高，生长速度快，稔性正常，可在生产上应用的四倍体大白菜材料和多育１、２、３ 相似文献
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Extracting features from biomedical signals to provide some decision support for medical diagnoses is an important aspect in the development of biomedical engineering.Analyzing power spectra of pulse signals for 15 heroin addicts and 15 healthy persons and calculating the power distributions on specified frequency bands for every power spectrum based on spectral estimation in this paper,we find that the significant difference of power distributions exists between the heroin addicts and the healthy persons.A primary criterion is also obtained,upon which the 13 cases of 15 heroin addicts are identified.The research result of this paper shows that the frequency domain analysis for pulse signals of heroin addicts is really an effective method. 相似文献
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the virtual boundary element method is applied for the numerical solution of a Signorini problem, which is conduced by an electro-paint process. The present method base on a switching algorithm, which can be applied to the problem defined in a non-regular domain, and it can reach good accuracy with less elements. 相似文献
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In the drive response method of Pecora and Carroll (the PC method), the response system is copied directly from drive system and is steady subsystem of drive system. But sometimes the PC method is disabled. Therefore, another method of realizing the drive response of chaos systems is put forward in this paper. The response system is not copied directly from steady subsystem of drive system, but is constructed from arbitrarily state variable of drive system. At the same time, the driving function is added in the response system, and the method of construction is pointed out. The method can realize the chaos synchronization that can not be realized by PC method. 相似文献
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Based on strong isomorphism for hypergraphs,vertex isomorphism is defined,which preserves hyper-adjacency property between vertices.Adjacency-matrixes of hypergraphs and weighted hypergraphs are presented respectively.The Floyd's algorithm is generalized to finding shortest paths between all pairs of vertices in a hypergraph.The publication provides an instance which verifies the practicability of the modified algorithm and whose results have been compared with those of the method given by LI Chun-ming.Time complexity of the presented algorithm is obtained to be(O(n~3)). 相似文献
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Magneteroheogical Fluids have very wide application due to the particular magneteroheogical effect. It is the key to develop ment of magneteroheological fluids and application to research on the magneteroheological effect. This paper discusses the magnetorheological effect for Magnetorheological (MR) fluids from the view of theory and experiment. It describes the influence of the applied magnetic field, volume fraction of the particles and the size of the magnetic particles on the rheological effect of MR fluids. It is shown that the experiment result agrees with the theoretic one. That provide the basis for the engineering development and the engineering applications. 相似文献
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Landfill site is one of the most important sources of greenhouse gas emissions. The available information shows that greenhouse gas emissions from the landfill sites are 40% 50% of the total greenhouse gas emissions in America. The greenhouse gas output is computed in the text and the conclusion that the main components of yielding gas are food and paper is made. Some measures of cutting greenhouse gas yielding are suggested. At last it points out that some research about these measures should be made in the future in China. 相似文献
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Luo Chunlei Sun Hongbo Xu Guoyu 《保鲜与加工》1997,(4):76-80
This paper first analyzes the internal dynamic process of the UPFC,then a five order differential equation is presented to describe dynamic behavior of UPFC. In term of this,a optimal control system is designed.Dynamic simulation of a transmission system demonstrates the effectiveness. 相似文献
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Mining sequential pattern is an important topic in the data mining research. In this paper, on the basis of recording the Ctid scheme of the set in every frequent set, the authors propose an algorithm named ISP for mining sequential pattern. In the algorithm the items and the sequence are discussed respectively, and the time join method is used to introduce the candidate sets, so the frequent sets can be gotten. The ISP algorithm takes full use of the existing and updated Ctid scheme, therefore the efficiency of the process is increased besides guaranteeing the validity of the algorithm. Comparing with the algorithm named IMSP,more efficient rules are obtained. 相似文献
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Electrorheological(ER) fluid is a mixed fluid , which consists of a fluid, non-elctronic particles, and some additive. ER fluid causes the strong interest in the material field due to the particular Electrorheological effect. This paper discusses the mechanical property of ER fluid and presents a constitutive model to describe the rheological property with an applied electronic field based on a simple mechanical partten.The experimental result agrees with the model of ER fluid. 相似文献
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