Novel photoactive aggregates of rhodamine 6G: dequenched and quasi-stable aggregates induced by a dewetting process

Self-organized rhodamine 6G particles prepared by wetting/dewetting process of an ethanol solution on a hydrophilic glass surface exhibits fluorescence without quenching, showing a sharp linewidth of 2nm with a large redshift, which indicates an existence of dye aggregates, similar to J-aggregates, inside the particle. Polarized evanescent field excitation showed that the dye molecule's transition moment along the pi-conjugation was oriented unidirectionally within particles and parallel to the substrate surface. This deduced dye orientation showed correlation between adjacent, but separated, particles and pointed roughly 45 degrees off the dewetting direction. In contrast, the particles of another pi-conjugated NK1420 dye, J-aggregates of which grows easily from an oversaturated solution, showed dye orientation along the dewetting direction preferably, still indicating the effect of self-organization, however based on a different mechanism. An annealing procedure revealed that both aggregates are in quasi-stable states, which is consistent with the rapidness of the dewetting process that may lead to crystallization in nonequilibrium.     

A new scaling algorithm for the maximum mean cut problem

We present a new scaling algorithm for the maximum mean cut problem. The mean of a cut is defined by the cut capacity divided by the number of arcs crossing the cut. The algorithm uses an approximate binary search and solves the circulation feasibility problem with relaxed capacity bounds. The maximum mean cut problem has recently been studied as a dual analogue of the minimum mean cycle problem in the framework of the minimum cost flow problem by Ervolina and McCormick. A networkN=(G, lower, upper) with lower and upper arc capacities is said to be -feasible ifN has a feasible circulation when we relax the capacity bounds by ; that is, we use (lower(a)- , upper(a)+) bounds instead of (lower(a), upper(a)) bounds for each arca A. During an approximate binary search we maintain two bounds,LB andUB, such thatN is LB-infeasible andUB-feasible, and we reduce the interval size (LB, UB) by at least one-third at each iteration. For a graph withn vertices, m arcs, and integer capacities bounded byU, the running time of this algorithm is O(mn log(nU). This time bound is better than the time achieved by McCormick and Ervolina under thesimilarity condition (that is,U=O(n^o(1))). Our algorithm can be naturally used for the circulation feasibility problem, and thus provides a new scaling algorithm for the minimum cut problem.Research supported by a grant-in-aid of the Ministry of Education, Science and Culture of Japan.     

环介导等温核酸扩增技术快速检测产毒亚历山大藻

DNA环介导等温扩增(LAMP)方法是一种新型的核酸扩增技术,该方法是在等温的条件下进行的,具有反应时间短、灵敏度高、特异性强的特点.本文以产麻痹性贝毒(PSP)的亚历山大藻为研究对象,采用简易法提取DNA模板,设计特异性LAMP引物,利用LAMP技术进行产毒藻种的快速检测,同时,着重对LAMP技术与PCR技术在检测微小亚历山大藻细胞的灵敏度方面做了比较.向LAMP终产物中加入SYBR Green I 染料后可直接用肉眼观察结果而不需要通过凝胶电泳来观察.结果表明,LAMP技术在恒温65℃,1h内就可以检测到产毒藻种;LAMP技术检测微小亚历山大藻的最低检测限为200个/ml,而PCR技术的最低检测限为1000个/ml,LAMP扩增方法比PCR扩增方法的程序简单、反应时间短、灵敏度高;LAMP技术不需要精密的温度循环装置,有恒温加热设备就可以满足检测条件,可用于野外检测.     

Thermoelectric Properties of NdGd<Subscript>1+<Emphasis Type="Italic">x</Emphasis></Subscript>S<Subscript>3</Subscript> Prepared by CS<Subscript>2</Subscript> Sulfurization

Ternary rare-earth sulfides NdGd_1+x S₃, where 0 ≤ x ≤ 0.08, were prepared by sulfurizing Ln₂O₃ (Ln = Nd, Gd) with CS₂ gas, followed by reaction sintering. The sintered samples have full density and homogeneous compositions. The Seebeck coefficient, electrical resistivity, and thermal conductivity were measured over the temperature range of 300 K to 950 K. All the sintered samples exhibit a negative Seebeck coefficient. The magnitude of the Seebeck coefficient and the electrical resistivity decrease systematically with increasing Gd content. The thermal conductivity of all the sintered samples is less than 1.9 W K⁻¹ m⁻¹. The highest figure of merit ZT of 0.51 was found in NdGd_1.02S₃ at 950 K.     

Nonlinear repetitive control with application to trajectory control of manipulators

In this article, a new control scheme named repetitive control is proposed for a class of nonlinear systems described by x(t) = Ax(t) + Bu(t) + n(x(t)) and y(t) = Cx(t), in which the controlled variables follow periodic reference commands. The stability condition is derived by applying the passivity theorem. We show how to apply the repetitive control scheme to the trajectory control of a manipulator. A simple repetitive control scheme is developed for the trajectory control of a manipulator by using nonlinear compensation and feedbacks of position and velocity signals. Experimental results for a three link manipulator verify that the proposed repetitive control reduces the tracking error to a very low level.     

模拟流体中真核状态鞭毛运动和纤毛运动的放大推进机构

由于大部分的生物体都具有相对的自发性、功能性和有效率性，模仿生物体动作的机械研究在工程领域是非常重要的。根据这个观点，我们研究了一种基于水中微生物动作的微型推进机构。     

Refinement of inverter model considering dead‐time for performance improvement in predictive instantaneous current control

Model predictive instantaneous‐current control (MPIC), which was proposed in our earlier works, enables us to achieve better instantaneous current control using mathematical models of an inverter and permanent magnet synchronous motors (PMSMs). However, dead‐time to avoid short breakdown in the inverter is not usually considered in a general inverter model. Such an unmodeled part in the inverter model prevents accurate prediction of current evolution in motor systems based on the model predictive control. Therefore, in this paper, we analyze current response resulting from the dead‐time in the MPIC, and propose a refined inverter model considering the dead‐time so that control performance is improved. The effectiveness of the proposed method is verified through simulation and experiments. © 2013 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

Compact electrostatic levitator for diffraction measurements with a two axis diffractometer and a laboratory x-ray source

A compact electrostatic levitator was developed for the structural analysis of high-temperature liquids by x-ray diffraction methods. The size of the levitator was 200 mm in diameter and 200 mm in height and can be set up on a two axis diffractometer with a laboratory x-ray source, which is very convenient in performing structural measurements of high-temperature liquids. In particular, since the laboratory x-ray source allows a great amount of user time, preliminary or challenging experiments can be performed with trial and error, which prepares and complements synchrotron x-ray experiments. The present small apparatus also provides the advantage of portability and facility of setting. To demonstrate the capability of this electrostatic levitator, the static structure factors of alumina and silicon samples in their liquid phases were successfully measured.     

Fabrication of fluorine-terminated diamond-like carbon thin film using a hyperthermal atomic fluorine beam

Surface modification of diamond-like carbon (DLC) film was performed using a hyperthermal atomic fluorine beam on the purpose of production of hydrophobic surface by maintaining the high hardness of DLC film. By the irradiation of atomic fluorine beam of a 1.0 × 10²⁰ atoms/cm², the contact angle of a water drop against the DLC surface increased from 73° to 111°. The formation of CF₃, CF₂ and CF bonding on the modified DLC surface was confirmed from the measurements of X-ray photoelectron spectra and near-edge X-ray absorption fine structure spectra. Irradiation of hyperthermal atomic fluorine beam was concluded to produce insulator fluorine-terminated DLC film, which has high F content on the surface, by the taking of the use of neutral atomic beam as a fluorine source.