Operation of vehicles in AGV system and method for analyzing operation

It is important to discuss the behavior of traffic at merging sections for the design and realization of an automated guided vehicle system (AGVS). In this study, we deal with a merging section of the AGVS by considering the time limit for the merging of vehicles. Near the merging section, the traffic flow in one direction forms a queue to avoid collisions between vehicles. We present an improvement of the control strategy proposed in previous research. However, since it is difficult to analyze the mathematical model of the merging section, analysis can be performed only for the case in which the time limit is set to the least values. We also propose a method for analyzing the model for an arbitrary time limit by using a linear recurrence relation. We discuss quantitatively the influence of the time limit on the average queue length and the detour rate. © 2011 Wiley Periodicals, Inc. Electr Eng Jpn, 178(1): 56–68, 2012; Published online in Wiley Online Library ( wileyonlinelibrary.com ). DOI 10.1002/eej.21190     

The atomic structure of disordered ion tracks in magnesium aluminate spinel

Atomic resolution transmission-electron microscopy (TEM) observations and analysis have been undertaken on magnesium aluminate spinel to understand the structure of ion tracks induced by swift heavy ions. A combination of TEM techniques, which includes high-resolution and bright-field (BF) imaging, and high angular resolution electron channeling spectroscopy (HARECXS) analysis, disclosed the atomic structure of ion tracks. Swift heavy ions induce cation disordering along the latent tracks for a widespread region of 10 nm in diameter, which is much larger than a strained region detected by BF diffraction contrast. A preferential migration of cations is induced from the tetrahedral to octahedral interstitial site at the core regions of ion tracks under a condition of higher electronic excitation of (dE/dx)_e = 35 keV/nm.     

The effect of Nb and W alloying additions to the thermal expansion anisotropy and elastic properties of Mo<Subscript>5</Subscript>Si<Subscript>3</Subscript>

The directional thermal expansion and elastic properties of Mo₅Si₃, (Mo_0.8Nb_0.2)₅Si₃, and (Mo_0.85W_0.15)₅Si₃ have been studied as a function of temperature through the use of single crystals. Thermal expansion anisotropy was reduced by Nb and W alloying. The decrease in thermal expansion anisotropy by Nb alloying was only found to occur at low temperatures, and thermal expansion anisotropy of (Mo_0.8Nb_0.2)₅Si₃ was similar to that for the other two compounds at 800 °C. Values for the polycrystalline Young’s, bulk, and shear moduli calculated from the measured single-crystal elastic constants are reduced by Nb alloying, and increased by W alloying at all temperatures studied. The elastic modulus E was calculated for the orientations between [100]-[001] and [100]-[010]. In contrast to the effects of Nb on thermal expansion anisotropy, Nb alloying increased the E _[001]/E _[100] elastic anisotropy. This article is based on a presentation made in the symposium entitled “Beyond Nickel-Base Superalloys,” which took place March 14–18, 2004, at the TMS Spring meeting in Charlotte, NC, under the auspices of the SMD-Corrosion and Environmental Effects Committee, the SMD-High Temperature Alloys Committee, the SMD-Mechanical Behavior of Materials Committee, and the SMD-Refractory Metals Committee.     

Role of Steric Hindrance in the Performance of Superplasticizers for Concrete

Interparticle potential energy calculations were performed to investigate the mechanisms by which a new class of concrete admixtures, generally referenced as poly(carboxylic acid)-type (PC) superplasticizers, which aid in dispersing cement particles, are formed. These calculations consisted of long-range Van der Waals, electrostatic, and steric interactions. The repulsive potential that resulted from electrostatic interactions was negligible, which would allow cement particles to flocculate in the absence of steric contributions. A model was developed to describe the adsorption behavior of these superplasticizers, which consisted of grafted polyethylene oxide (PEO) chains on a PC backbone on cement surfaces. Using this adsorption model, the influence of the length of the PEO molecular chain and the density per unit area on the steric contribution was quantified. Steric hindrance effects were the dominant stabilizing mechanism in this system. As expected, enhanced stability was observed with increasing adlayer thickness (and/or density). The results of this study may be useful in designing the molecular structure of this new and important class of dispersion aids for cement-based systems.     

A small molecule CXCR4 inhibitor that blocks T cell line-tropic HIV-1 infection

Several members of the chemokine receptor family have been shown to function in association with CD4 to permit human immunodeficiency virus type 1 (HIV-1) entry and infection. The CXC chemokine receptor CXCR4/fusin is a receptor for pre-B cell growth stimulating factor (PBSF)/stromal cell-derived factor 1 (SDF-1) and serves as a coreceptor for the entry of T cell line-tropic HIV-1 strains. Thus, the development of CXCR4 antagonists or agonists may be useful in the treatment of HIV-1 infection. T22 ([Tyr5,12,Lys7]-polyphemusin II) is a synthesized peptide that consists of 18 amino acid residues and an analogue of polyphemusin II isolated from the hemocyte debris of American horseshoe crabs (Limulus polyphemus). T22 was found to specifically inhibit the ability of T cell line-tropic HIV-1 to induce cell fusion and infect the cell lines transfected with CXCR4 and CD4 or peripheral blood mononuclear cells. In addition, T22 inhibited Ca2+ mobilization induced by pre-B cell growth stimulating factor (PBSF)/SDF-1 stimulation through CXCR4. Thus, T22 is a small molecule CXCR4 inhibitor that blocks T cell line-tropic HIV-1 entry into target cells.     

打濑小学

这是一所正在修建中的小学校园，距离Utase小学（设计于1996年）只有500m。许多生活在Makuhari Baytown的居民对于Utase小学所提供的教育水准和校园环境非常满意，基于这样的原因，这座建筑完全沿袭了Utase小学的设计模式。学校一旦开学，就会有大量的学生入学，这在日本是十分罕见的情形，尤其是在出生率下降的今天。我们所设计的这所小学能够容纳24个教室和960名小学生。     

Preventive control in an autonomous decentralized system

For more rational operation and control of future electric power systems which would continue to expand in size and complexity, an autonomous decentralized control system is proposed as one of the new control architectures. In the autonomous decentralized control system, each generating station and substation behaves independently and cooperatively without being controlled by the central station. Besides the inherent fault-tolerant characteristics of the architecture, flexible and rapid control depending on the circumstances can be achieved. In this paper, the fundamental logic of preventive control in an autonomous decentralized system is developed. It is based on the bidding method in which each station proposes its own output taking into consideration its own situation and cooperation with others. The economic load dispatch including preventive control can be performed, based on the bidding rule adopting the equivalent incremental generating cost curve in which the security constraints are incorporated. Application of the logic to a model system revealed satisfactory control performance for preventing the overload of transmission lines and the undervoltage.     

A 3.5-ns, 500-mW, 16-kbit BiCMOS ECL RAM

A 16-kbit BiCMOS ECL SRAM with a typical address access time of 3.5 ns and 500-mW power dissipation was developed. The RAM was fabricated using half-micrometer, triple-poly, and triple-metal BiCMOS technology. The fast access time with moderate power dissipation has been achieved using new circuit techniques: a grounded-gate, nonlatching-type level converter with a wired-OR predecoder and a direct column sensing scheme having a cascode differential amplifier. As a result of extensive use of high-speed bipolar ECL circuits with self-aligned bipolar transistors, the RAM attains high-speed performance without degrading the low-power BiCMOS RAM characteristics.<>