相位损耗对Jaynes-Cummings模型的动力学性质的影响

运用密度算符间距研究了一位于相位损耗腔中大失谐二能级原子与相干光场相互作用系统中原子、光场及系统各态随时间的演化规律,讨论了原子初态、光场的平均光子数和相位损耗对Jaynes-Cummings模型动力学行为的影响.     

SPOT卫星影像数据在长输管道工程中的应用

SPOT卫星影像具有较高的分辨率，广泛应用于基础地理信息的更新和跨越区域工程建设中，可以为拟建的长输管道通过地区提供新的工程环境信息，应用SPOT卫星影像数据技术可以长输管道工程在节约投资，缩短建设周期，减灾防灾等方面提供了有效的技术保障。     

长输油气管道的焊接技术

介绍了国内外输油气管道的三种主要焊接方法,重点分析了国内近几年新建管道不同焊接方法的使用情况,同时对不同焊接方法的选用和管材与焊接材料的选用匹配进行了探讨和研究.     

方格法测量土方量精度的研究

运用误差传播定律分析方格网法计算土方量的理论精度,结果表明:(1)在距离为100m范围内,水准仪、经纬仪和全站仪测量地面高程、方格法计算土石方量的相对中误差分别为4%、8%和2%。(2)随着测量仪器精度的提高,土地平整过程中土方量测量计算的容许误差应由过去的10%提高到6%。(3)用反距离加权插值法计算方格顶点高程可提高方格网法计算土方量的精度。     

Chromosomal location of a gene (Rkn-mnl) for resistance to the root-knot nematode transferred into wheat from Aegilops variabilis

Root-knot nematode is a significant root-parasite of common wheat. A dominant gene Rkn-mnl for resistance was transferred into wheat from Acgilops variabilis. This gene was shown to be on chromosome 3B. Further analysis indicated that it is on the long arm of this chromosome and independent of the centromere.     

Recommended isolation distances for the field multiplication of diploid tuber-bearing Solanum species

The sexual propagation of genebank accessions by hand pollination in the greenhouse is a very expensive and time-consuming routine task. The self-incompatibility of most diploid potato species allows their multiplication in isolated field plots, which is coupled with the advantage of the presence of natural pollinators and maintaining a high level of heterozygosity. The aim of this study was to determine the isolation distance required for minimizing pollen flow between neighbouring multiplication plots. The Solanum phureja clone IVP48 was used as the pollen donor since it possesses a dominant seed marker (‘embryo spot’). The centrally located pollen donor was surrounded by S. phureja recipient plots at distances of 10,20,40, and 80 m, respectively. The average pollen contamination ranged from 0.2% in the plots 80 m from the pollen donor to 5.1% in those 10 m away. In this study, procedures are suggested which will help to reduce cross-pollination between accessions.     

Studies on Low Crossabilities Encountered with the Hordeum bulbosum Method for Haploid Production of Barley, Hordeum vulgare L.

Crosses were made between four spring barley (Hordeum vulgare L.) cultivars and five F₁, hybrids with one genotype of Hordeum bulbosum L. in two locations to investigate further previous low crossabilities which had been found in the barley cultivar ‘Apex’ with H. bulbosum. Data at all the main steps of the H. bulbosum technique were recorded and statistically analyzed. Significant differences between barley genotypes were demonstrated for all characters. It was confirmed that ‘Apex’ has poor crossability with H. bulbosum. Out of the three F₁ hybrids having ‘Apex’ as one parent, two exhibited low crossability similarly to ‘Apex’ but one showed significantly higher seed setting than ‘Apex’. The effect of the location was only significant on seed setting, while genotype X location interactions were significant on seed setting, seed quality and rate of haploid plants in relation 10 florets pollinated. Another problem which has influenced the success rate of the H. bulbosum method was found in the cultivar ‘Havilla’. Although seed setting and seed quality were high for this cultivar, embryo differentiation was low. However, this latter problem was found to influence less the overall success rate than poor crossability. Mahalanobis's distances were calculated and the dendrite of the shortest distances between barley genotypes was plotted.     

DYNAMIC ANALYSIS OF ASYMMETRIC FRAME-SHEAR WALL SYSTEM BY STAGE CONTINUITY METHOD

The lateral structures of frame-shear wall system are simplified into bending beams and shear beams which stiffness can vary in different stages along the building height. The three-dimension stiffness matrix and mass matrix are deduced, and the characteristic equation is established to calculate the tortuous free vibration of the asymmetric system. The method is simple and has satisfactory precision, and it is easily fulfilled in micro-computers.     

An investigation of the relationship between the F1 potential and the measures of genetic distance among wheat lines

Summary Three groups of characters selected using three methods were used to calculate genetic distance among two groups of winter wheat lines using Euclidean distance based on principal components. These wheat lines were then clustered by the unweighted pair-group arithmetic average method. The relationship between genetic distance and standardized potence was seemingly influenced by genetic materials. In order to obtain promising crosses, it is advisable to select parents from intercluster rather than intracluster materials. The results suggested that the repeatability method was better than the conventional and weighting methods for selecting characters for distance analysis.     

AN IMPROVED TRANSFER SUBSTRUCTURE METHOD

The transfer substructure method is extended to application in substructures with different linking ways,thus the field of application of this method is expanded. Its relaibility and efficacy are proved by some examples.