-X86历史之旅

通过三个方面介绍CPU的发展历史进程,并展望其未来。     

蒙脱石/聚丙烯酰胺插层复合材料的制备及结构表征

利用蒙脱石层间域活性，合成蒙脱石／聚丙烯酰胺（Mntmorillonite-PAM)插层复合物，并用X－射线衍射，傅立叶变换红外光谱，差热分析等分析测试手段对插层复合物的结构进行表征。     

国产X80直缝埋弧焊接钢管力学性能测试

对国产X80直缝埋弧焊接钢管(JCOE工艺)进行了拉伸、夏比冲击、显微硬度和落锤撕裂等力学性能测试,结果表明,该钢管的各项性能均符合API SPEC 5L(43版)的指标要求,说明我国已经具备了生产高强度高韧性X80直缝埋弧焊管的能力.     

Exchangeability of Two hrp Gene Fragments from Xanthomonas oryzae pv.oryzae and pv.oryzicola for Hypersensitive Response on Tobacco and Pathogenicity on Rice

hrp- mutants were produced from strain JXOIII of Xanthomonas oryzae pv.oryzae (Xoo) and strain RS105 of X.o.pv.oryzicola (Xooc), respectively, by using diethyl sulfate (DES) as a mutagenic che-mical. All the hrp- mutants lost their pathogenicity on a susceptible host plant, rice (Shanyou63), and elicitation of the hypersensitive response (HR) on a nonhost plant, tobacco (NC89). Extracellular enzyme (amy-lase, pectate lyase, proteinase, cellulase and lipase) activities of all the hrp- mutants were similar to those of the corresponding wild type strains. The response of tobacco to cell-sonicated integrations of the wild type strains and the hrp- mutants demonstrated that there existed an HR eliciting substance which was heat-stable and sensitive to protease. No HR appeared on tobacco after infiltration of the lipopolysaccharide (LPS) of both the wild strains and hrp mutants into tobacco leaves. The ability of the Xooc hrp- mutants to induce HR on tobacco and cause streak disease on rice was restored by complementation with pUHRX245 from JXOIII genomic DNA library and by pUHRS138 from RS105 genomic DNA library, respectively. Subcloning of a 38.6-kb hrp fragment insert in pUHRX245 and a 39.3-kb insert in pUHRS138 revealed that a 3.3-kb SacⅠ fragment from pUHRX245 and a 4.5-kb BamHⅠ-KpnⅠ fragment from pUHRS138 were the minimal functional portions required for restoration of the ability of Xooc hrp- mutants to induce HR on tobacco and cause disease on rice. The disease symptom caused by the conjugant (M1005 plus 3.3-kb) on rice was similar to that caused by the wild type of Xooc. It suggests that the two fragments contain the same hrp gene(s) and are responsible reciprocally for HR induction on tobacco and pathogenicity on rice.     

手扶拖拉机X型悬架座椅的研究

为了改善手扶拖拉机驾驶员的乘坐舒适性能,本文给出了一种预紧的X型悬架座椅,并对该悬架进行了理论解析,测定了它的静态特性和手扶拖拉机在凹凸不平道路上行驶时的隔振性能,同时也与手扶拖拉机原海棉弹簧座椅及ISO2631中的振动规范曲线进行了比较。     

Wheat Substitutions in Hexaploid Triticale*

Crosses between octoploid and hexaploid triticales have been made m breeding programs for several years, From an analysis of the progeny of such crosses where selections for an octoploid-like phenotype had been made, it was established that 149 out of 150 lines were hexaploid in chromosome number, C-banding and in situ hybridization demonstrated that all but five of the 62 lines analyzed in detail contained visible chromosomes or segments from the D genome. Only four lines had D-genome chromosome replacing rye chromosomes. All of the remaining 53 D-genome substitutions involved the replacing of wheat chromosomes from either the A or B genomes. This establishes the ease with which D-genome genes can be placed into triticale without the loss of rye chromosomes.     

Leaf Waxes of Cassava (Manihot Esculenta Crantz) in Relation to Ecozone and Resistance to Xanthomonas Blight

Summary To elucidate the role of leaf surface structures as first barriers to confer resistance to bacterial blight, leaf stomata and their occlusion with leaf waxes were studied in cassava genotypes. For the first time, cassava leaf waxes were quantitatively and qualitatively analysed. Comparing the susceptible and resistant standard genotypes BEN86052 and TMS30572, respectively, the total quantity of triterpenes was significantly higher in the resistant genotype, grown in three ecozones of Benin. In cuticular leaf waxes of seven cassava genotypes the triterpenes beta amyrins, epi-taraxerol, taraxerone and taraxerol were dominant constituents across genotypes, and alkanes (C₂₅-C₃₃) and acids (C₃₀ and C₃₂) occurred in minor concentrations. Comparing seven genotypes, no clear relation between resistance or ecozones and total quantities of the major wax constituents was observed. Only the highly resistant genotype TMS30572 showed high triterpene levels irrespective of ecozone. Scanning electron-microscopy revealed a regular distribution of waxes at the abaxial leaf surface, covering and occluding stomatal pores of susceptible and resistant genotypes, while on the adaxial leaf surface waxes were in form of crystalloids and did not occlude the stomata. The number of stomata on the abaxial surfaces was about 7–11 fold higher than on the adaxial surfaces, where stomata were located along the midrib and major veins. No significant differences in stomata number were observed between genotypes varying in resistance to bacterial blight. It is suggested, that stomata on the adaxial surface might be portals of entry for the bacteria.     

Genetics and histology of powdery mildew resistance in apple

Summary Eight scab-resistant cultivars and selections along with eight commercial apple cultivars were evaluated for powdery mildew resistance in greenhouse and nursery tests. Dayton, Liberty, Delicious and Tolman Sweet were rated moderately resistant to infection in both greenhouse and nursery tests. Segregation of seedlings among 14 progenies for mildew reaction indicated that mildew resistance is polygenically controlled in this material with additive gene effects. Recovery of mildew resistant seedlings from crosses involving a scab-resistant parent(s) suggested that this material can be useful in developing scab- and mildew-resistant apple cultivars. Histological investigations were conducted to describe mildew symptoms of infected leaves.     

Searching for DNA introgressed from wheat and for wheat-like grain proteins in a rice x wheat hybridization derivative

The DNA of a putative rice x wheat hybridization derivative (X Oryticum oryzoides) from China, the DNA of its parental rice cultivar and the DNA of a wheat line were digested with ten different restriction endonucleases, resolved by agarose electrophoresis, Southern blotted and hybridized using genomic wheat DNA as a probe. Phenol extracted, ethanol and cetyltrimethylammonium bromide precipitated DNA of the putative hybrid showed a restriction fragment length polymorphism (RFLP) different from that of the parental rice. When the DNA was further purified by Qiagen chromatography, the RFLP differences were not detected. Hence the apparent RFLP differences were probably due partial digestion of the less pure DNA preparations by the restriction endonucleases. No real introgressed fragments from wheat genome could be shown. The HpaII/MspI sites were more frequently digested with MspI than with HpaII in rice and hybridization derivative DNA, but the sites were evidently more frequently methylated in wheat DNA. Thus, in terms of methylation of the DNA, the hybridization derivative was much more like the rice parent than the wheat parent. The hybridization derivative showed a single endospermal protein (mass 19 kg mol^-1) not detected in the parental rice cultivar. This minor protein was soluble in buffered 50% isopropanol and precipitable with methanol. The results indicate that there are no or only short introgressed sequences from wheat in the rice/wheat derivative, a result which might be considered in breeding efforts with the hybrid derivative.