Exotic behaviour of angular dispersion of weakly bound nucleus F-17 at small angles

The differential cross sections of F-17 and O-17 elastic scattering products on Pb-208 have been measured at the Radioactive Ion Beam Line at Lanzhou (RIBLL). Two angular dispersion plots of ln(d sigma/d theta) versus theta 2 are obtained from the angular distribution of the elastic scattering differential cross sections. The angular dispersion plot exhibits a clear turning point for F-17 in the range of small scattering angles 6 degrees-20 degrees due to its exotic structure, but for O-17, the turning point is not observed in the same angular range. The experimental results have been compared with previous data of other groups. Systematical analysis on the available data supports the above conclusion that there is an exotic behaviour of the angular dispersion plot of weakly bound nuclei with halo or skin structure as compared with that of the ordinary nuclei near stable line. Therefore the turning point of the angular dispersion plot appears at small angle for weakly bound nuclei with halo or skin structure, and can be used as a new probe to investigate the halo and skin phenomena of weakly bound nuclei.

CONSISTENT THREE-BODY FORCE WITH BONN B POTENTIAL AND NEUTRON STAR STRUCTURE

Microscopic three-nucleon force consistent with the Bonn B two-nucleon potential is constructed, which includes Delta(1232), Roper, and nucleon-antinucleon excitation contributions. Recent results for the choice of the meson parameters are discussed. The forces are used in Brueckner calculations and the saturation properties of nuclear matter are determined. At the high densities,the nuclear equation of state and the symmetry energy are calculated. The corresponding neutron star mass-radius relations are presented.

缺硫对万寿菊镉积累的影响

采用营养液培养法,研究了缺硫对万寿菊(Tagetes erecta)各器官镉积累的影响,以及巯基化合物和有机酸等在各器官镉积累中的作用。结果表明:0.1 mg.L-1镉处理7 d,缺硫处理显著降低了植物根、茎和叶中的镉含量,较对照分别降低了47%、38%和61%;缺硫对植物体内半胱氨酸、γ-谷氨酰半胱氨酸、谷胱甘肽和有机酸的合成没有显著影响,而且3种巯基化合物的含量都很低;缺硫植物根部合成的植物络合素的量显著降低,这可能是植物体内镉积累减少的主要原因;在植物的各器官中,叶片中的有机酸含量最高,而在叶片中未检测到植物络合素,由此可推断,叶片中积累的镉主要与有机酸结合;缺硫影响了根部植物络合素的合成,进而降低了植物体内镉的积累,而缺硫没有影响植物体内有机酸的合成,有机酸可能仅是参与植物组织中与镉的络合作用。

生物表面活性剂产生菌的筛选及表面活性剂稳定性研究

大庆油田油泥样品经富集培养,平板分离,获得52株菌。排油性实验和表面张力测定表明,菌株B22、B24、B25产生的表面活性剂表面活性稳定,表面张力较低。温度、pH和NaCl浓度实验证实,细菌B22产生的生物表面活性剂可耐受120℃高温,另2种生物表面活性剂可耐受80℃;3种细菌生物表面活性剂对pH有广泛适应性,B22pH适应范围为4·0~13·0,B24、B25的pH适应范围为2·0~13·0;Na-Cl浓度对表面活性剂的生物活性影响不大。将3株菌的生物表面活性剂用于室内油泥处理实验,72h石油去除率达70%以上。

Improved Melting Strength of Polypropylene by Reactive Compounding With Ultrafine Full-Vulcanized Polybutadiene Rubber (UFBR) Particles

Ultrafine full-vulcanized polybutadiene rubber (UFBR) in particle sizes of ca. 50-100 nm has been used for modifying mechanical and processing performances of polypropylene (PP), and PP-g-maleic anhydride (PP-MA) has been used as a compatibilizer for enhancing the interfacial adhesion between the two components. The results show that PP/UFBR possesses rheological behaviors such as highly branched PP when UFBR content in blends reaches 10 wt%, while in contrast, the much low content of UFBR combining small amount of PP-MA endows the material with rheological characteristics of high melt strength materials like highly branched PP.

A simple and low-cost airlift photobioreactor for microalgal mass culture

A simple, low-cost, and efficient airlift photobioreactor for microalgal mass culture was designed and developed. The reactor was made of Plexiglas, and composed of three major parts: outer tube, draft tube and air duct. The fluid-dynamic characteristics of the airlift reactor were studied. The system proved to be well suited to the mass cultivation of a marine microalga, Chlorella sp. In batch culture, the biomass volumetric output rate of 0.21 g l(-1) d(-1) was obtained at the superficial gas velocity of 4 mm s(-1) in the draft tube.

Population genetics of Crassostrea ariakensis in Asia inferred from microsatellite markers

Crassostrea ariakensis is an important aquacultured oyster species in Asia, its native region. During the past decade, consideration was given to introducing C. ariakensis into Chesapeake Bay, in the United States, to help revive the declining native oyster industry and bolster the local ecosystem. Little is known about the ecology and biology of this species in Asia due to confusion with nomenclature and difficulty in accurately identifying the species of wild populations in their natural environment. Even less research has been done on the population genetics of native populations of C. ariakensis in Asia. We examined the magnitude and pattern of genetic differentiation among 10 wild populations of C. ariakensis from its confirmed distribution range using eight polymorphic microsatellite markers. Results showed a small but significant global theta (ST) (0.018), indicating genetic heterogeneity among populations. Eight genetically distinct populations were further distinguished based on population pairwise theta (ST) comparisons, including one in Japan, four in China, and three populations along the coast of South Korea. A significant positive association was detected between genetic and geographic distances among populations, suggesting a genetic pattern of isolation by distance. This research represents a novel observation on wild genetic population structuring in a coastal bivalve species along the coast of the northwest Pacific.

唐古特大黄的粉末X射线衍射图谱

采用粉末X射线衍射法对3个唐古特大黄和1个掌叶大黄样品进行分析,获得了唐古特大黄的特征峰值及标准X射线衍射图谱.

藏药大果大戟中的巨大戟烷型二萜酯类成分

目的研究藏药大果大戟Euphorbia wallichii丙酮提取物中的化学成分。方法用溶剂提取，常规硅胶柱色谱分离和葡聚糖凝胶Sephadex LH-20纯化，采用化学方法和现代波谱分析技术（包括IR，HRESIMS，HRSIMS，1D和2DNMR等）鉴定其化学结构。结果从青海产大果大戟根的丙酮提取物中分离得到6个化合物，分别鉴定为：羊毛甾醇（lanosterol，Ⅰ）、巨大戟二萜-20-肉豆蔻酸酯（ingenol-20-myristinate，Ⅱ）、巨大戟二萜-3-肉豆蔻酸酯（ingenol-3-myristinate，Ⅲ）、没食子酸（gallicacid，Ⅳ）、1-O-a-L-阿拉伯糖-（1→6）-β-D-葡萄糖苷-3，7-二甲基-2-烯-7-羟基-辛醇（1-O-a-L-arabinofuranosyl-（1→6）-β-D-glucopyranosyl-3，7-dimethyl-oct-2-en-7-ol，Ⅴ）、1-O-没食子酰葡萄糖苷（1-O-galloyl-β-D-glucose，Ⅵ）。结论巨大戟烷型二萜酯类化合物Ⅱ和Ⅲ为新化合物，其他化合物均为首次从该植物中分离得到，单萜二糖苷类化合物Ⅴ系首次在该属中发现。

CAD/CAM一体化的应用与开发

文章概要地介绍了CAD/CAM系统的结构、CAD/CAM一体化的工作流程,提出实现CAD/CAM一体化的几种可行方案,并以具体零件机床为例,给出从设计到数控编程和机床加工的全过程。

一个用于自治智能移动式机器人导航和监控的实验系统

文中重点讨论了系统实现过程中,任务分解与行走命令下达,时序分配与同步,路标定位与行走误差修正.动态障碍感知,测定与响应和特别情况紧急处理等难题的解决策略及遇到的问题.