The genome sequence and structure of rice chromosome 1

The rice species Oryza sativa is considered to be a model plant because of its small genome size, extensive genetic map, relative ease of transformation and synteny with other cereal crops. Here we report the essentially complete sequence of chromosome 1, the longest chromosome in the rice genome. We summarize characteristics of the chromosome structure and the biological insight gained from the sequence. The analysis of 43.3 megabases (Mb) of non-overlapping sequence reveals 6,756 protein coding genes, of which 3,161 show homology to proteins of Arabidopsis thaliana, another model plant. About 30% (2,073) of the genes have been functionally categorized. Rice chromosome 1 is (G + C)-rich, especially in its coding regions, and is characterized by several gene families that are dispersed or arranged in tandem repeats. Comparison with a draft sequence indicates the importance of a high-quality finished sequence.     

医学科研选题的原则及技巧

科研选题是科研工作的关键环节。科研选题应根据学科专业的特点，把握需求性原则、创新性原则、科学性原则与可行性原则，采用恰当的方法技巧，确定高水平、高质量的选题。     

Mlgebraic Attack on Filter-Combiner Model Keystream Generators

Algebraic attack was applied to attack Filter-Combiner model keystream generators. We proposed thetechnique of function composition to improve the model, and the improved model can resist the algebraic attack. A new criterion for designing Filter-Combiner model was also proposed: the total length L of Linear Finite State Machines used in the model should be large enough and the degree d of Filter-Combiner function should be approximate [L/2].     

Assembling Zwitterionic, Water-Soluble Porphyrin and Its Biological Studies

A kind of zwitterionic water-soluble porphyrin 5-(N-trimethyl-4-aminiumphenyl)-10, 15, 20-tri (4-sulfonatephenyl) porphyrin trisammonium salt, has been synthesized. Its biological studies, interactions with DNA and bacteria cells, were investigated. The damage to the cell wall of bacteria E. coli were observed firstly by AFM (Atomic Force Microscope).     

Some Results about the Sample Path Properties of Markov Processes with Independent Self-Similar Components

This paper considers a special class of operator self-similar processes Markov processes {X（t）, t≥0} with independent self-similar components, that is, X （ t ） =（X^1（t）,…,X^d（t））, where {X^i（t）,t≥0}, i=1,2,…,d are d independent real valued self-similar Markov processes. By means of Brel-Cantelli lemma, we give two results about asymptotic property as t→∞ of sample paths for two special classes of Markov processes with independent self-similar components.     

理论和实验DNA计算

本书是《自然计算系列》丛书之一。近10年来，DNA计算迅速地发展成为计算科学、生物学、工程和数学之间的新研究领域。此书全面地介绍DNA计算的整个领域、历史和发展，书中详细论述至今已有的所有理论模型和实验结果，也讨论了将来可能的发展。     

Linear sand ridges on the outer shelf of the East China Sea

Based on the latest full-coverage high-resolution multi-beam sounding data, the distribution of the linear sand ridges on the outer shelf of the East China Sea （ECS） is studied with quantitative statistical analysis. The study area can be divided into the northeastern part and the southwestern part. Sand ridges in the northeastern area, trending 116°N, show obvious linear character and shrink to the inner shell Sand ridges in the southwestern area, trending 120°N -146°N, tend to have net form. Sand ridges gradually become sand sheets in the center part of study area. Sand ridges are distributed landward to the isobath of 60m, distributed seaward to the water depth of 120 m in the northeast and 150 m in the southwest. Immature sand ridges are observed at water depth of 130-180 m in the southwestern depressions. The acoustic reflection properties of the internal high.angle inclined beddings of the sand ridges are analyzed based on the typical seismic profiles close to the research area. Lithological analysis and dating of 4 boreholes and 12 cores indicate that the widely distributed transgressive sand layer with high content of shell debris which was formed in the early-middle Holocene is the main composition of the linear sand ridges on the outer shelf of the ECS. The dominating factor in formation, developing and burying of the sand ridges is the variation of water depth caused by sealevel change and the rate of sediment supply. In 12400 aBP the cotidal lines of the M2 tidal component were closely perpendicular to the strike-directions of the sand ridges in the study area, and the tidal wave system during 12000-8000 aBP might play a key role in the formation of the linear sand ridges which are widely distributed on the outer shelf of the ECS.     

A high-performance thermoacoustic refrigerator operating in room-temperature range

The working principle of an efficient travelling- wave thermoacoustic refrigerator operating in room-temperature range has been analyzed and an experimental set-up has been built. The experiment showed that suppressing DC-flow streaming was very critical to efficient operation, and an elastic membrane was used to solve the problem successfully. At the most efficient operating point, the novel thermoacoustic refrigerator achieved a cooling capacity of about 80 W at -20℃, with a much higher efficiency than previously developed standing-wave thermoacoustic refrigerator.     

项目管理中的问题分析及其解决方法

阐述项目管理中进行问题分析的必要性,分析项目管理中问题分析的内涵、解决方法和决策方法。认为项目管理的问题需要在反馈信息的基础上反复分析,重视管理人员与项目发起人之间的沟通;要分析问题的性质、适时地在里程碑处进行小结、制订管理目标、建立管理效果评价指标、识别管理过程中的约束,通过多种渠道收集问题的解决方法,并尽可能地考虑各种因素,当问题分析清楚之后,就要进行决策。     

浊点萃取-火焰原子吸收光谱法测定水样中痕量铅的研究

提出了浊点萃取-火焰原子吸收光谱法测定痕量铅的新方法,并详细探讨了溶液pH值、试剂浓度等实验条件对浊点萃取及测定灵敏度的影响.在最佳条件下,富集50 mL样品溶液,用火焰原子吸收光谱法测定,铅的检测限为0.82μg/L,铅的富集倍数为66倍.该方法可用于自来水、井水及河水中痕量铅的测定.