79 resultados para ALLIUM CEPA TEST


Relevância:

20.00% 20.00%

Publicador:

Resumo:

Charge stripping is employed to produce multi-charged ions for injecting the cooling storage ring After penetrating through the carbon foil, the widened distribution of ion charge states poses a limit to the ion injection Therefore, the carbon foil plays a key role in the charge snipping injection In this paper, foul strippers for Heavy Ion Research Facility at Lanzhou (HIRFL) and Cooling Sun age Ring (CSR) are introduced The charge state distribution of the stripped ions is measured and the stripping efficiency of the foils is investigated The experimental results are consistent with the theoretical values

Relevância:

20.00% 20.00%

Publicador:

Resumo:

为测量重离子加速器冷却储存环(HIRFL-CSR)的外靶实验终端上不同能量的γ射线,一种用于探测γ射线的高能量分辨的探测装置正在中国科学院近代物理研究所建设,该探测器由中国科学院近代物理研究所自行生长的铊激活的碘化铯CsI(Tl)晶体组成。与日本Hamamatsu公司生产的S8664-1010型雪崩光二极管(APD)耦合,测试其光输出的非均匀性和能量分辨,从测试结果给出了所需CsI(Tl)晶体合格的标准。目前已完成该γ探测球计划的六分之一,所提供的晶体合格率达94%以上。

Relevância:

20.00% 20.00%

Publicador:

Resumo:

In the construction of a large area neutron detector (neutron wall) that is used to detect neutrons at GeV energies, the performances of all the sampling paddle modules prepared for the neutron wall are investigated with a specially designed test bench. Tested by cosmic rays, an average intrinsic time resolution of 222.5 ps is achieved at the center of the modules. The light attenuation length and the effective speed of the light in the module are also investigated.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

利用30,90,180Gy3种剂量的12C6+重离子束辐照大葱种子,研究其在细胞水平和农艺性状的诱变效应并进行RAPD分析。通过与M1代的研究结果比较后表明:经过不同剂量12C6+重离子照射后能有效地诱导大葱细胞形成微核和染色体畸变,这种诱变效应,在M2代仍然有所表现。M1代大葱结果期的株高、白长、花序直径和种子产量随辐照剂量增加产生明显差别,其中30Gy辐照组增幅最大。大葱总水溶性蛋白质和维生素C的含量在30Gy组中积累最多,在90Gy组有明显下降。与M1代一致,M2代中大葱染色体微核率及RAPD分析所得的DNA多态性比率仍然与辐照剂量呈正相关,但比率整体下降;说明高能量重离子辐照造成的DNA变异在M2代被修复和淘汰。

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Chinese Academy of Sciences (ISCAS)

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Association for Computing Machinery, ACM; IEEE; IEEE Computer Society; SIGSOFT

Relevância:

20.00% 20.00%

Publicador:

Resumo:

A novel "gold electrode-molecular wires-silver" junction was facilely fabricated for electrochemical study on the electron transportation through molecular wires. Rapid electron transportation through this sandwich-like structure was indeed observed by cyclic voltammograms and ac impedance measurements. Since rather reproducible and reliable results are easily available by electrochemical techniques, it would be an efficient and reliable test bed for electrochemical investigation of charge transportation through molecular wires in self-assembled monolayers on electrodes.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

In "high nitrate, low chlorophyll" (HNLC) ocean regions, iron has been typically regarded as the limiting factor for phytoplankton production. This "iron hypothesis" needs to be tested in various oceanic environments to understand the role of iron in marine biological and biogeochemical processes. In this paper, three in vitro iron enrichment experiments were performed in Prydz Bay and at the Polar Front north of the Ross Sea, to study the role of iron on phytoplankton production. At the Polar Front of Ross Sea, iron addition significantly (P < 0.05, Student's t-test) stimulated phytoplankton growth. In Prydz Bay, however, both the iron treatments and the controls showed rapid phytoplankton growth, and no significant effect (P > 0.05, Student's t-test) as a consequence of iron addition was observed. These results confirmed the limiting role of iron in the Ross Sea and indicated that iron was not the primary factor limiting phytoplankton growth in Prydz Bay. Because the light environment for phytoplankton was enhanced in experimental bottles, light was assumed to be responsible for the rapid growth of phytoplankton in all treatments and to be the limiting factor controlling field phytoplankton growth in Prydz Bay. During the incubation experiments, nutrient consumption ratios also changed with the physiological status and the growth phases of phytoplankton cells. When phytoplankton growth was stimulated by iron addition, N was the first and Si was the last nutrient which absorption enhanced. The Si/N and Si/P consumption ratios of phytoplankton in the stationary and decay phases were significantly higher than those of rapidly growing phytoplankton. These findings were helpful for studies of the marine ecosystem and biogeochemistry in Prydz Bay, and were also valuable for biogeochemical studies of carbon and nutrients in various marine environments.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The small mysid crustacean Neomysis awatschensis was collected in the west coast of Jiaozhou Bay, Qingdao, China in 1992 and acclimated and cultured in laboratory conditions since then. Standard acute toxicity tests using 4-6 d juvenile mysids of this species were conducted and the results were compared with Mysidopsis bahia, a standard toxicity test organism used in the US in terms of their sensitivities to reference toxins, as well as their taxonomy, morphology and geographic distributions. Because of its wide distribution along the Chinese coast, similar sensitivity to pollutants as M. bahia, short life history, small size and the case of handling, this study intended to use N. awatschensis as one of the standard marine organisms for toxicity testing in China. The species were applied to acute toxicity evaluations of drilling fluid and its additives I organotin TPT and toxic algae, and to chronic ( life cycle) toxicity assays of organotin TPT and a toxic dinofalgellate Alexandrium tamarense, respectively. Using N, awatschensis as a standard toxicity testing organism in marine pollution assessment in China is suggested.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The present work is first reporting the hemolytic activity of venom from jellyfish Rhopilema esculentum Kishinouye extracted by different phosphate buffer solutions and incubated at different temperature according to the orthogonal test L6(1) x 3(6). Of the seven controllable independent variables, incubated temperature and phenylmethylsulfonyl fluoride (PMSF) had strongest effect on the hemolytic activity. (c) 2006 Elsevier B.V. All rights reserved.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Polyploidization plays an important role in generating the current high diversity of plants. Studies of distributional patterns of diploids and derivative autopolyploids have provided important insights into evolutionary processes and cryptic speciation of polyploidization within species defined on the basis of their morphology. However, few studies have been designed to examine distributions of infrageneric diploids and polyploids on the Asian Qinghai-Tibetan Plateau (QTP). Allium przewalskianum occurs widely on the QTP and in adjacent regions, at altitudes ranging from 2000m to 4500m. We collected a total of 844 individuals from 62 populations and determined their cytotypes over the entire distribution range of this species. Tetraploids tend to occur at high altitudes; however, the positive relationship between the ploidy and altitude was only marginally significant (P < 0.05). Contact zones between diploids and tetraploids were recorded on the eastern QTP from north to south. Four populations were found to harbor both cytotypes, but no triploid individuals. The wider distribution of tetraploids may be mainly due to their greater colonization ability in the new niches created by the Quaternary climatic oscillations in the QTP region. Our results offer a fundamental framework for studying evolutionary origins, adaptations and cryptic divergences of polyploids within this species complex based on molecular and/or ecological examinations in the future.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Milula, a monotypic genus endemic to the Qinghai-Tibetan Plateau, was found to be nested deeply within Allium by the molecular phylogeny despite the aberrant morphology. It remains unknown what had contributed to the rapid evolution of morphology and origin of this exceptional species. In contrast to a previous report of its karyotypes with 2n = 16 = 8M+8SM (2SAT), similar to most species of Allium, a rather different karyotype, 2n = 20 = 4M +10SM+6T (2SAT), was found in examined 31 individuals from 6 populations of M. spicata distributed in the central Tibet. Karyotypes of 7 Allium species occurring in the Qinghai-Tibetan Plateau were further reported. The basic number x = 8 was confirmed for all of them and their karyotypes consist mainly of metacentric and submetacentric chromosomes with rare subterminal and terminal chromosomes. The karyotype of M. spicata is distinctly different from that of most Allium species occurring in the plateau through a complete comparison of all available species in this region and adjacent areas. However, the same chromosome number and similar karyotypic structure were found in A. fasciculatum of Sect. Bromatorrhiza, indicating a possible close relationship between them. But this similarity is contradictory to the preliminary molecular phylogenetic analysis that Milula was closely related to A. cyathophorum of Sect. Bromatorrhiza with x=8, but the other species with x=10 and 11 in this section were clearly placed in the other clade. We therefore suggested that the paralleling evolution from x=8 to x=9, 10 and 11 with increasing asymmetry of karyotype possibly due to the chromosomal Robertsonian translocation might occur separately in the two recognized phylogenetic lineages of Allium. In addition to aneuploidy and following change of the chromosomal structures, the habitat isolation due to the recent uplift of the Qinghai-Tibetan Plateau and the Quaternary climatic oscillation, plays a greater role in origin of Milula and other endemic species (genera) with aberrant morphology from their progenitors.