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991.
Haruo Mimura Ryusei Sato Yu Sasaki Yuichi Furuyama Akira Taniike Kazutoshi Yoshida Akira Kitamura 《International journal of molecular sciences》2008,9(10):1989-2002
Tributyltin (TBT) released into seawater from ship hulls is a stable marine pollutant and obviously remains in marine environments. We isolated a TBT resistant marine Pseudoalteromonas sp. TBT1 from sediment of a ship’s ballast water. The isolate (109.3 ± 0.2 colony-forming units mL−1) adsorbed TBT in proportion to the concentrations of TBTCl externally added up to 3 mM, where the number of TBT adsorbed by a single cell was estimated to be 108.2. The value was reduced to about one-fifth when the lysozyme-treated cells were used. The surface of ethanol treated cells became rough, but the capacity of TBT adsorption was the same as that for native cells. These results indicate that the function of the cell surface, rather than that structure, plays an important role to the adsorption of TBT. The adsorption state of TBT seems to be multi-layer when the number of more than 106.8 TBT molecules is adsorbed by a single cell. 相似文献
992.
认为止水材料的蠕变和应力松弛是由于材料参数的变化而引起的,把描述橡胶类材料应变能密度函数中的物理参数假设成与时间有关的黏弹性函数。在此基础上改进材料应力张量与应变张量的关系式,得到了改进的Mooney-Rivlin公式,给出了一种考虑止水材料黏弹性性质的伸缩式水封仿真计算方法。分析得出,止水材料由于受周边结构的限制,材料黏弹性阶段除顶点垂直位移不变,关键结点的其它位移并没有因材料的蠕变而显著变化,材料的蠕变有提高封头顶点接触应力的趋势,不会降低水封的水密性。通过工程实例,给出了140m水头下、封头与面板间隙控制在30mm内的可行并较优的伸缩式水封的断面。 相似文献
993.
Gijsbert Erkens Jeroen Janssen 《International Journal of Computer-Supported Collaborative Learning》2008,3(4):447-470
Although protocol analysis can be an important tool for researchers to investigate the process of collaboration and communication,
the use of this method of analysis can be time consuming. Hence, an automatic coding procedure for coding dialogue acts was
developed. This procedure helps to determine the communicative function of messages in online discussions by recognizing discourse
markers and cue phrases in the utterances. Five main communicative functions are distinguished: argumentative, responsive, informative, elicitative, and imperative. A total of 29 different dialogue acts are specified and recognized automatically in collaboration protocols. The reliability
of the automatic coding procedure was determined by comparing automatically coded dialogue acts to hand-coded dialogue acts
by a human rater. The validity of the automatic coding procedure was examined using three different types of analyses. First,
an examination of group differences was used (dialogue acts used by female versus male students). Ideally, the coding procedure
should be able to distinguish between groups who are likely to communicate differently. Second, to examine the validity of
the automatic coding procedure through examination of experimental intervention, the results of the automatic coding procedure
of students, with access to a tool that visualizes the degree of participation of each student, were compared to students
who did not have access to this tool. Finally, the validity of the automatic coding procedure of dialogue acts was examined
using correlation analyses. Results of the automatic coding procedure of dialogue acts of utterances (form) were related to
results of a manual coding procedure of the collaborative activities to which the utterances refer (content). The analyses
presented in this paper indicate promising results concerning the reliability and validity of the automatic coding procedure
for dialogue acts. However, limitations of the procedure were also found and discussed. 相似文献
994.
995.
介绍了EASY2000色谱处理系统在酒类产品分析实际应用过程中的方法,步骤,特点及注意事项等。 相似文献
996.
In this study, a single unit of planar micro-solid-oxide fuel cell (μSOFC) is investigated numerically to evaluate the influences of flow channel design, oxygen composition, and thermal operating conditions on cell performance. Four flow channel designs are examined under the co-flow configuration: serpentine, double serpentine, rod bundle, and oblique rib. For all designs, the contacts areas of interconnect to electrodes are kept consistent to maintain the ohmic losses at the same level. To characterize the mass transport effects, there are three different compositions, 100% O2, 50% O2/50% N2 and air, fed to the cathode inlet. Different thermal conditions, adiabatic and isothermal, are applied to the outer boundary of the μSOFC and the results are compared. The outcomes suggest that both thermal conditions and oxidant composition show remarkable influences on μSOFC performance. Under adiabatic conditions, the rise of cell temperature causes a decrease in reversible voltage, deteriorating the overall cell competence. When oxygen is diluted with nitrogen, local gas diffusion becomes dominant to the cathode reaction. Bulk flow, on the other hand, plays a minor role in cell performance since there is little deviation in the polarization curves for all flow channel designs, even at high current densities. For comparison, the flow visualization technique is employed to observe the transport phenomena in various flow channel designs. The flow patterns are found to resemble the concentration distribution, providing a useful tool to design μSOFCs. 相似文献
997.
A model warehouse with carefully regulated environmental conditions was used to study the behavior of adult Indian meal moths during commodity infestation. Sequences of moth distributions in the warehouse, calculated by spatial analysis, clearly showed the coordinated movements of moth populations from eclosion to death. Many facets of adult behavior in a warehouse were coordinated with the photoperiod. Adult moths emerged at the end of a photophase and fairly rapidly moved to the walls and, to a lesser extent, to the undersides of the commodity pallets. Most females are mated in the first 24 h after emergence, largely during the scotophase. Air circulation within the warehouse probably compromised pheromone-directed guidance of males to females, although pheromones may still have a major role in regulating other aspects of male mating behavior. When mating subsided, many of the males flew upwind to the air circulating unit, but only during the photophases. The females moved to the return air side of the warehouse and then migrated towards the same end as the males, but only during the scotophases. They moved from pallet to pallet largely by walking on the warehouse floor and laid eggs in or on the cups of commodity. Direct oviposition on the commodity during the infestation period was lower than expected, probably because commodity odors were dissipated by air circulation and did not provide appropriate orientation. At 144 h after emergence, 90% of the moth population had died. 相似文献
998.
以三聚磷酸钠生产过程为例,论述了在以纯碱为原料的非强酸性水溶液体系中,由于反应不完全导致反应物中存在少量的碳酸盐,这部分碳酸盐干扰了用酸碱滴定法测量的中和度,并据此提出中和度分析改进方法.由此可以推广到其它以纯碱为原料的非强酸性水溶液体系中. 相似文献
999.
1000.