兰州重离子治癌研究装置的准直测量技术；Survey and alignment for the heavy ion therapy facility at IMP

介绍了中国科学院近代物理研究所重离子治癌装置的安装定位测量技术和方法。利用激光跟踪仪通过控制网的建立,和多重坐标系的转换,使最后的磁铁安装径向相对误差不超过±(0.05-0.1)mm,真空管道的横向及竖向精度也达到了±(0.1-0.2)mm。

Drift distance survey in direct plasma injection scheme for high current beam production

In a laser ion source, plasma drift distance is one of the most important design parameters. Ion current density and beam pulse width are defined by plasma drift distance between a laser target and beam extraction position. In direct plasma injection scheme, which uses a laser ion source and a radio frequency quadrupole linac, we can apply relatively higher electric field at beam extraction due to the unique shape of a positively biased electrode. However, when we aim at very high current acceleration such as several tens of milliamperes, we observed mismatched beam extraction conditions. We tested three different ion current at ion extraction region by changing plasma drift distance to study better extraction condition. In this experiment, C6+ beam was accelerated. We confirmed that matching condition can be improved by controlling plasma drift distance.

Analytical intercomparison results from the 1990 Intergovernmental Oceanographic Commission open-ocean baseline survey for trace metals: Atlantic Ocean

“Dissolved” (< 0.4 μm filtered) and “total dissolvable” (unfiltered) trace element samples were collected using “clean” sampling techniques from four vertical profiles in the eastern Atlantic Ocean on the first IOC Trace Metals Baseline expedition. The analytical results obtained by 9 participating laboratories for Mn, Fe, Co, Ni, Cu, Zn, Cd, Pb, and Se on samples from station 4 in the northeast Atlantic have been evaluated with respect to accuracy and precision (intercomparability). The data variability among the reporting laboratories was expressed as 2 × SD for a given element and depth, and was comparable to the 95% confidence interval reported for the NASS seawater reference standards (representing analytical variability only). The discrepancies between reporting laboratories appear to be due to inaccuracies in standardization (analytical calibration), blank correction, and/or extraction efficiency corrections.Several of the sampling bottles used at this station were not adequately pre-cleaned (anomalous Pb results). The sample filtration process did not appear to have been a source of contamination for either dissolved or particulate trace elements. The trace metal profiles agree in general with previously reported profiles from the Atlantic Ocean. We conclude that the sampling and analytical methods we have employed for this effort, while still in need of improvement, are sufficient for obtaining accurate concentration data on most trace metals in the major water masses of the oceans, and to enable some evaluation of the biogeochemical cycling of the metals.

Microspheres and microcapsules, a survey of manufacturing techniques: Part III: Solvent evaporation

A methodological survey of microsphere formation and microencapsulation techniques based on solvent extraction/evaporation techniques is presented. Thus, basic features of solvent extraction and solvent evaporation processes, including droplet formation, droplet/particle stabilization, and solvent removal, are outlined. Preparation of a wide range of microspherical and microcapsular products based on biodegradable polyesters, polysaccharides, and nonbiodegradable polymers are discussed. Dependence of microcapsule characteristics on manufacturing parameters, as well as performance evaluation of microspherical and microcapsular products, are also briefly covered.

On-line voltammetric monitoring of dissolved Cu and Ni in the Gulf of Cadiz, south-west Spain

Geochemical processes in estuarine and coastal waters often occur on temporally and spatially small scales, resulting in variability of metal speciation and dissolved concentrations. Thus, surveys, which are aimed to improve our understanding of metal behaviour in such systems, benefit from high-resolution, interactive sampling campaigns. The present paper discusses a high-resolution approach to coastal monitoring, with the application of an automated voltammetric metal analyser for on-line measurements of dissolved trace metals in the Gulf of Cadiz, south-west Spain. This coastal sea receives metal-rich inputs from a metalliferous mining area, mainly via the Huelva estuary. On-line measurements of dissolved Cu, Zn, Ni and Co were carried out on-board ship during an eight-day sampling campaign in the study area in June 1997. A pumping system operated continuously underway and provided sampled water from a depth of ca. 4 m. Total dissolved metal concentrations measured on-line in the Gulf of Cadiz ranged between <5 nM Cu (<3 nM Ni) ca. 50 km off-shore and 60–90 nM Cu (5–13 nM Ni) in the vicinity of the Huelva estuary. The survey revealed steep gradients and strong tidal variability in the dissolved metal plume extending from the Huelva estuary into the Gulf of Cadiz. Further on-line measurements were carried out with the automatic metal monitor from the bank of the Odiel estuary over a full tidal cycle, at dissolved metal concentrations in the μM range. The application confirmed the suitability of the automated metal monitor for coastal sampling, and demonstrated its adaptability to a wide range of environmental conditions in the dynamic waters of estuaries and coastal seas. The near-real time acquisition of dissolved metal concentrations at high resolution enabled an interactive sampling campaign and therefore the close investigation of tidal variability in the development of the Huelva estuary metal plume.

ASSIGNMENT OF C-13 NMR-SPECTRA OF POLYMER WITH SEMIEMPIRICAL METHOD - SURVEY OF SPECTRUM OF SECONDARY CARBON OF 1,2-PBD

In chain molecules of 1, 2-PBD, there are two kinds of gauche arrangements, which is the cause of making the spectrum of the secondary carbon in main chain of the polymer split. In such a complex system, the gauche arrangements of the secondary carbon and the tertiary carbon occupy an important position. Hence, the contribution of the tertiary carbon to the chemical shifts of the secondary carbon has a decisive effect on the sequence structure distribution. In comparison the contribution of vinyl groups is ...

Genome-wide survey of putative serine/threonine protein kinases in cyanobacteria

Background: Serine/threonine kinases (STKs) have been found in an increasing number of prokaryotes, showing important roles in signal transduction that supplement the well known role of two-component system. Cyanobacteria are photoautotrophic prokaryotes able to grow in a wide range of ecological environments, and their signal transduction systems are important in adaptation to the environment. Sequence information from several cyanobacterial genomes offers a unique opportunity to conduct a comprehensive comparative analysis of this kinase family. In this study, we extracted information regarding Ser/Thr kinases from 21 species of sequenced cyanobacteria and investigated their diversity, conservation, domain structure, and evolution. Results: 286 putative STK homologues were identified. STKs are absent in four Prochlorococcus strains and one marine Synechococcus strain and abundant in filamentous nitrogen-fixing cyanobacteria. Motifs and invariant amino acids typical in eukaryotic STKs were conserved well in these proteins, and six more cyanobacteria- or bacteria-specific conserved residues were found. These STK proteins were classified into three major families according to their domain structures. Fourteen types and a total of 131 additional domains were identified, some of which are reported to participate in the recognition of signals or substrates. Cyanobacterial STKs show rather complicated phylogenetic relationships that correspond poorly with phylogenies based on 16S rRNA and those based on additional domains. Conclusion: The number of STK genes in different cyanobacteria is the result of the genome size, ecophysiology, and physiological properties of the organism. Similar conserved motifs and amino acids indicate that cyanobacterial STKs make use of a similar catalytic mechanism as eukaryotic STKs. Gene gain-and-loss is significant during STK evolution, along with domain shuffling and insertion. This study has established an overall framework of sequence-structure-function interactions for the STK gene family, which may facilitate further studies of the role of STKs in various organisms.

Genome-wide survey of putative serine/threonine protein kinases in cyanobacteria

Background: Serine/threonine kinases (STKs) have been found in an increasing number of prokaryotes, showing important roles in signal transduction that supplement the well known role of two-component system. Cyanobacteria are photoautotrophic prokaryotes able to grow in a wide range of ecological environments, and their signal transduction systems are important in adaptation to the environment. Sequence information from several cyanobacterial genomes offers a unique opportunity to conduct a comprehensive comparative analysis of this kinase family. In this study, we extracted information regarding Ser/Thr kinases from 21 species of sequenced cyanobacteria and investigated their diversity, conservation, domain structure, and evolution. Results: 286 putative STK homologues were identified. STKs are absent in four Prochlorococcus strains and one marine Synechococcus strain and abundant in filamentous nitrogen-fixing cyanobacteria. Motifs and invariant amino acids typical in eukaryotic STKs were conserved well in these proteins, and six more cyanobacteria- or bacteria-specific conserved residues were found. These STK proteins were classified into three major families according to their domain structures. Fourteen types and a total of 131 additional domains were identified, some of which are reported to participate in the recognition of signals or substrates. Cyanobacterial STKs show rather complicated phylogenetic relationships that correspond poorly with phylogenies based on 16S rRNA and those based on additional domains. Conclusion: The number of STK genes in different cyanobacteria is the result of the genome size, ecophysiology, and physiological properties of the organism. Similar conserved motifs and amino acids indicate that cyanobacterial STKs make use of a similar catalytic mechanism as eukaryotic STKs. Gene gain-and-loss is significant during STK evolution, along with domain shuffling and insertion. This study has established an overall framework of sequence-structure-function interactions for the STK gene family, which may facilitate further studies of the role of STKs in various organisms.

Trace element composition of peridotites from the southern Mariana forearc: Insights into the geochemical effects of serpentinization and/or seafloor weathering

Peridotites from the southern Mariana forearc were sampled on the landward trench slope of the Izu-Bonin-Mariana (IBM) subduction zone by dredging. These mantle wedge peridotites underwent hydration by fluid derived from a dehydrated descending slab, and later interacted with seawater after emplacement at or near the seafloor. This study investigates how these two different rock-fluid interaction processes influenced trace element distribution in the southern Mariana forearc peridotites. We measured trace element concentrations of peridotites from the southern Mariana forearc. The southern Mariana forearc peridotites are characterized by a distinct seawater-like REE pattern with an obvious negative Ce anomaly, and La shows good correlation with other REEs (except Ce). In addition, there is a great enrichment of U, Pb, Sr and Li elements, which show a distinct positive anomaly relative to adjacent elements in the multi-element diagram. For the seawater-like REE pattern, we infer that REEs are mainly influenced by seawater during peridotite-seawater interactions after their emplacement at or near the seafloor, by serpentinization or by marine weathering. Furthermore, the anomalous behavior of Ce, compared with other rare earth elements in these samples, may indicate that they have undergone reactions involving Ce (IV) when the peridotites interacted with seawater. Positive U, Pb, Sr and Li anomalies are inferred to be related to seawater and/or fluids released during dehydration of the subducting slab.

Geochemical properties of the variolitic andesite from Susong in the Dabie orogenic belt, China

The variolitic andesite from the Susong County in the Dabie Mountains implies that it was erupted in water. The mineralogy of the varioles is primarily radiate plagioclase (albite sind oligoclase), with little pyroxene, hornblende and quartz (derived from alteration). The pyroxene, hornblende and quartz are in the interstices between plagiocalse. The matrix consists of glass, hornblende, chlorite, epidote and zoisite. It is clearly subjected an extensive alteration. The andesite has an uncommon chemical composition. The SiO2 content is about 56.8%, TiO2 = 0.9%, MgO = 6.4%, Fe2O3 (tot) = 6.7%similar to 7.6%, 100Mg/(Mg + Fe) = 64.1 similar to 66.2. Mg-# is significantly high. The andesite has high abundances of large-lithophile trace elements (e.g. K, Ba. Sr, LREE), e.g. La/Nb = 5.56 similar to 6.07, low abundances of high-strength-field elements (HFSE e.g. Ta, Nb, P, Ti), particularly Ta and Nb strongly depleted. These are consistent with the characteristics of subduction-related magmas. In the spider diagram of trace elements, from Ce to right hand, the abundances of elements decrease quickly, showing a character of the continental margins. There has a strong punishment of light-rare-earth elements, with a significant diffraction of REEs (the mean value of (La/Yb)(N) is 32.84). No Eu anomaly, but there are anomaly high (La/Yb)(N) = 28.63 similar to 36.74, (La/Y)(N) = 70.33 similar to 82.4. The elements Y and Yb are depleted greatly, Y<20 g/g, Y-N = 2.74 similar to 2.84, Yb-N = 2.18 similar to 2.35. From the La-(La/Sm) diagram, the andesite is derived from partial melting. But the epsilone value of Nd is - 18.7 similar to -19.2, so that the material source may be the mantle materials affected by the crustal materials. The Nd model age is 1.9 Ga indicating that the variolitic basaltic andesite was resulted from the mantle wedge of North China block, which had the Nd model age of 2.5Ga, when the Yangze block which had the Nd model age of 1.7Ga subducted beneath it. So the variolitic andesite has characteristics of the island-are volconic rocks oil a continental basement in the vicinity of the destructive continental margin.