加速器质谱测量129I方法的改进

在筑波大学的12UD串列加速器上开发了一套改进的129I加速器质谱(AMS)测量方法,包括在120°磁铁后安装了一副自行设计制作有静电偏转板,有效改善了对127I束流和129I计数的测量;采用97MoO2分子导航束稳定加速器端电压,加速器的端电压能稳定在几天内不超过0.1%,结合二次剥离,取得了满意的测量效果.用该方法测得AgI试剂样品的本底水平为7.83×10-13.对129I/127I比值范围为(4.92～0.28)×10-10的一系列样品的测量不确定度在7%以下,准确度较前有所提高.     

基于累积损伤理论的土石坝地震永久变形分析

以龙冈的在不规则荷载作用下土体应变的累积损伤理论为基础,提出了基于累积损伤理论的土石坝地震永久变形分析方法。采用大型静力和动力三轴仪,对某土石坝筑坝材料的静动变形特性进行了试验研究,确定了筑坝材料的静力和动力应力应变关系、累积应变模型和相应的材料参数。利用该方法,分别对在日本2008年6月14日岩手—宫城内陆M7.2级地震作用下该土石坝的在建坝体和竣工后坝体的地震永久变形特性进行了研究。结果表明：在建坝体的坝内沉降计算值与现场实测值基本吻合,并且通过与其它土石坝实测值的比较,说明竣工后坝体的坝顶沉降预测值在合理范围之内。     

Thermal Expansion and Chemical Durability of Phosphate Glasses

The thermal expansion coefficient and aqueous dissolution rate were measured for alkali phosphate glasses containing a third and fourth component. For a given series, both properties increased monotonically as the radii of the alkali ions increased. The observed expansion coefficients were in the range 99 to 286 × 10⁻⁷°C⁻¹. A small mixed-alkali effect was observed for both properties.     

Conjugation and H ∞ control of discrete-time systems

We establish conjugation notion in discrete-time systems, first introduced into the H ^∞ control theory of continuous-time systems by Kimura (1989). In discrete-time systems, conjugation is a very elementary operation on rational transfer functions that replaces some of their poles by their reflections with respect to the unit circle. With the aid of J-lossless conjugation conjugation by a J.lossless system), it is shown that the parametrization of sub-optimal solutions of H ^∞ model-matching problems is reduced to a Lyapunov-type equation. The parametrization of all solutions is given in an extremely simple way. It is further proved that the J-lossless conjugation of the H ^∞ model-matching problem is a natural state-space representation of classical interpolation in discrete-time systems.     

A LRT Control Method Using Sensor Information in Distribution Systems with a Large Amount of PVs and EVs

It is of prime importance to maintain voltage profile within the proper range in distribution systems with a large amount of photovoltaics and electric vehicles (EVs). In particular, there is a possibility that line drop compensation (LDC) logic, which is utilized for the control of load ratio tap transformer (LRT) does not work properly when reverse power flow is included partially. Hence, in this paper, we have developed a new LRT control method based on the sensor information supposing that some section switchgears with sensors are introduced in the future distribution systems. Specifically, the extreme value of voltage profile is estimated by convergence calculation in the section between the section switchgear with sensor and LRT. Moreover, the voltage at the end node can be estimated by LDC method using sensor information of section switchgear. The proposed method was tested using a distribution system model and its effectiveness was shown.     

日本水坝的安全管理和地震安全评价

日本是一个地震多发的国家,而特殊的地形又决定了水坝在其经济社会发展中具有重要的地位,因此水坝的安全管理和地震安全评价就成为一个至关重要的方面.     

Sensory Analysis of Taste-Active Components in the Extract of Boiled Snow Crab Meat

A synthetic extract, prepared from 44 pure chemicals on the basis of the analytical data on the leg meat extract of the boiled snow crab, Chionoecetes opilio, satisfactorily reproduced the taste of the natural extract except for a slight lack of body and mildness. A series of taste panel assessments on synthetic extracts prepared by omitting or adding extractive component(s) were carried out by a triangle difference test and changes in taste profile were assessed. Only 12 components, Ala, Arg, Glu, Gly, glycine betaine, AMP, CMP, GMP, Na⁺, K⁺, Cl^?, and PO₄^3-, were found to contribute more or less toward producing the characteristic taste of the snow crab.     

Further Studies on the Roles of the Head and Tall Regions of the Myosin Molecule in Heat-induced Gelation

Heat induced gelation properties of the two proteolytic fragments of myosin, heavy (HMM) and light meromyosin (LMM), were studied by rigidity measurement in a band type viscometer and by a direct examination using a scanning electron microscope. A heat induced network forming ability for both LMM and HMM was found in 0.6M KCl at a pH 6.0. LMM produced gels corresponding to a reversible helix-coil transition at temperatures ranging from 40–70°C, with little evidence of aggregation as assessed from a turbidity change of the system. Contrary, HMM associated irreversibly producing a gel with increased rigidity at pH 5.0 and a salt concentration of 0.1 M. Oxidation of SH-groups appeared to be involved only in HMM and not in LMM gelation process.