Profile structure of magnetic flux lines in type-II superconductor from a rectangular electron hologram

Profile magnetic configuration of a quantized flux line and flux-line lattice penetrating a type-II superconductor thin foil, niobium, was observed by electron holography and Lorentz microscopy using a 300 kV field-emission electron microscope. Each single flux line was distributed periodically as lattice structure in the mixed state just below its critical temperature of 8.5 K, while at low temperature of 5 K the flux lines were weakly bound as bundles. In order to observe the flux-line distribution over a wide area, discrete Fourier transform reconstruction in the holography was extended for a rectangular area without loss of information and data precision.     

CARD资源发现架构在无线传感网络中的性能研究

(西北工业大学计算机学院,陕西西安,710072)【摘要】CARD架构适用于大规模、高查询率、每次查询的数据传输量较小的Ad-hoc网络,它的核心目标是降低网络资源发现能耗,延长网络生命周期。文章首先介绍了CARD架构的结构;然后,建立了该架构的数学模型,该模型以无线传感器网络为目标场景,并推导出CARD架构的能耗和查询成功率与各个参数之间的函数关系;最后,根据该模型对CARD架构的能耗和查询成功率进行了理论分析,为CARD架构的参数选择提供了可靠的依据,并为对架构的进一步优化打下了坚实基础。     

Exoskeletal meal assistance system (EMAS II) for patients with progressive muscular disease

Patients with muscle weakness such as muscular dystrophy usually need someone’s assistance in their daily activities. In order to reduce the caregiver burden and to improve quality of life (QOL) of the patients, various robotic technologies have been developed. This paper presents an exoskeletal assistance system EMAS II for the patients, which assists the upper extremity for the purpose of daily activities such as eating, writing, or other desk works. The EMAS II assists four DOF; shoulder flexion-extension, shoulder abduction-adduction, shoulder medial-lateral rotation, and elbow flexion-extension. The EMAS II has three kinds of user interfaces which are operated by residual functions of the patients, because it is important for patients’ health and initiative to use the residual functions. In order to control the four DOFs exoskeleton system using the interfaces with less DOF, the EMAS II simulates upper limb motion patterns of healthy people. The patterns are modeled by extracting correlations between the height of the wrist joint and that of the elbow joint. Therefore, users have only to control the position of their wrist joint to do tasks at a table. Through an experiment with a healthy subject, the feasibility of meal assistance by the EMAS II was confirmed. Furthermore, the system was applied to a spinal muscular atrophy patient in a clinical trial to check the usability. The experimental results indicated that the EMAS II could support the patient’s upper extremity to do tasks at a table.     

Investigation of direct load management scheme with consideration of end‐user comfort

A direct load management scheme with two‐way communication, with consideration of end‐user comfort, is proposed. First, the control algorithm is developed and the data required to be transmitted between system operator and controllable loads are identified. Then, the actions of controllable air conditioners and the power adjustment of dispersed generators to eliminate overloads in a substation transformer are simulated. The results indicate that the proposed load management technique performs effectively to reduce overloads on the transformer while maintaining energy consumption in each load, and the performance is improved by coordination with the output of dispersed generators. © 2011 Wiley Periodicals, Inc. Electr Eng Jpn, 176(3): 19–28, 2011; Published online in Wiley Online Library ( wileyonlinelibrary.com ). DOI 10.1002/eej.21139     

Synthesis and hydrophilic property of polypropylene-graft-poly(polyethylene glycol-methacrylate) (PP-g-P(PEGMA))

Polypropylene-graft-poly(polyethylene glycol-methacrylate) (PP-g-P(PEGMA)), which is a hydrophobic-hydrophilic graft copolymer, was synthesized by a combination of an atom transfer radical polymerization (ATRP) of PEGMA with brominated polypropylene (PP-Br), which was synthesized from PP-OH prepared by metallocene-catalyzed copolymerization. Its structure was confirmed by ¹H NMR and GPC analyses. Transmission electron microscope (TEM) micrographs of PP-g-P(PEGMA) revealed the nanometer level microphase-separation morphology between the PP segment and the P(PEGMA) segment. The obtained PP-g-P(PEGMA) showed water-absorbing property as well as thermostability.     

Phospholipid polymer hydrogel formed by the photodimerization of cinnamoyl groups in the polymer side chain

We synthesized new polymers with both photocrosslinkability and biocompatibility by a random copolymerization of 4‐(4‐methoxycinnamoyl)phenyl methacrylate and 2‐methacryloyloxyethyl phosphorylcholine. These polymers were used as prepolymers to make a hydrogel by photoirradiation. Gelation began with 5 s of photoirradiation and reached an equilibrium state after 360 s of photoirradiation. The absorption maximum at 347 nm, attributed to the cinnamoyl group, disappeared with the photoirradiation time. That is, dimerization between cinnamoyl groups in the polymer proceeded and formed a hydrogel. The equilibrium water concentration of the hydrogels was more than 90%. Moreover, we succeeded in making a microshape hydrogel on glass by photoirradiation through a photomask. The window shape of the photomask was transferred to the hydrogel that was formed. We concluded that these photocrosslinkable polymers could be useful in preparing microfluidic devices for separating or immobilizing biomolecules and cells. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 44–50, 2007     

Limitations of the method using peroxidase activity of hemoglobin for detecting lipid hydroperoxides

The method using peroxidase activity of hemoglobin (Hb) for the determination of lipid peroxides was examined by using pure methyl linoleate hydroperoxides, trilinoleoylglycerol hydroperoxides and egg yolk phosphatidylcholine hydroperoxides as substrates and tetramethyl benzidine as electron donor for the peroxidase reaction of Hb. The reactivities of these substrates were quite varied. Furthermore, some electron donors were tested for peroxidase activity of Hb, but none showed a complete reduction of methyl linoleate hydroperoxides. From these results, it seems the Hb method needs to be carefully applied to biological materials that contain mixtures of different types of lipid classes.     

丝锥全生命周期参数对攻丝性能影响的研究

采用正交试验法完成了HSS/Co-M35含钴高速钢丝锥加工Ti-6Al-4V钛合金的攻丝试验。利用极差分析法研究了丝锥全生命周期参数即丝锥前角(刀具设计参数)、刃口钝化半径(刀具制造参数)、主轴转速(刀具使用参数)对攻丝性能的影响。利用综合评分法将扭矩max、轴向切削力max和切削温度max等3项攻丝性能指标转化为单一综合切削性能指标y*i,分析结果表明:攻钛合金时丝锥全生命周期参数取刃口钝化半径0.01 mm,丝锥前角10°,主轴转速150 r/min时最优。通过试验与数值模拟获得的扭矩值及趋势、切屑形态及切削刃对比图,验证了在Advant Edge FEM软件中建立的丝锥攻Ti-6Al-4V钛合金模型的可靠性。     

In situ preparation of nano ZnO/hyperbranched polyimide hybrid film and their optical properties

Novel hybrid films of fluorinated hyperbranched polyimide (HBPI) and zinc oxide (ZnO) were prepared via the in situ sol-gel polymerization technique, in which mono-ethanolamine (MEA) was used as the coupling agent between the termini of HBPI and the precursor of ZnO. The hybrid films were characterized by transmission electron microscopy (TEM), Fourier transform infrared (FT-IR) absorption, ultraviolet-visible (UV-vis) absorption, and fluorescent excitation/emission spectroscopy. The films, which originated from the colourless fluorinated HBPI structure and homogeneously dispersed ZnO nanoparticles, exhibited good optical transparency. Furthermore, two kinds of model compounds with and without ZnO and a HBPI film blended with ZnO microparticles were prepared to clarify the fluorescence mechanism in the pristine HBPI and in situ hybrid films. Efficient energy transfer from the ZnO nanoparticles to the aromatic HBPI main chains was observed in the in situ hybrid films, whereas energy transfer occurred only from the locally excited (LE) states to the charge-transfer (CT) state in the HBPI film. These facts demonstrate that the peripheral termini of HBPI are covalently bonded to ZnO particles via the MEA function, which operates as an effective pathway for energy transfer to give intense fluorescent emission.