On the pseudo-freeness and the CDH assumption

The notion of pseudo-free group was first introduced by Hohenberger (Master’s thesis, EECS Dept., MIT, 2003). Rivest (TCC 2004. LNCS 2951, 505–521, 2004) formalized it and showed that several standard cryptographic assumptions hold on pseudo-free groups, such as the RSA assumption, the strong RSA assumption and the discrete logarithm assumption. Rivest (TCC 2004. LNCS 2951, 505–521, 2004) also proposed some variations of pseudo-free group, and those were formalized by Hirano and Tanaka (Research Reports, Series C: Computer Science, C-239, Tokyo Institute of Technology, 2007). In this paper, we study the relationships among such variations of pseudo-free group. We show that the pseudo-freeness implies the weak pseudo-freeness, and that the pseudo-freeness is equivalent to the pseudo-freeness with generalized exponential expressions. We also show that the computational Diffie-Hellman assumption holds on pseudo-free groups in a slightly varied form.     

Feeder components and instrumentation for the JT-60SA magnet system

The modifying of the JT-60U magnet system to the superconducting coils is progressing as a satellite facility for ITER by both parties of Japanese government and European commission in the Broader Approach agreement. The magnet system requires current supplies of 25.7 kA for 18 TF coils and of 20 kA for 4 CS modules and 6 EF coils. The magnet system generates an average heat load of 3.2 kW at 4 K to the cryogenic system. The feeder components connected to the power supply provide current supply. The cooling pipes connected to the cryogenic system provide coolant supply. The instrumentation of the JT-60SA magnet system is used for its operation.     

A dynamic-programming-based exact algorithm for general single-machine scheduling with machine idle time

This paper proposes an efficient exact algorithm for the general single-machine scheduling problem where machine idle time is permitted. The algorithm is an extension of the authors’ previous algorithm for the problem without machine idle time, which is based on the SSDP (Successive Sublimation Dynamic Programming) method. We first extend our previous algorithm to the problem with machine idle time and next propose several improvements. Then, the proposed algorithm is applied to four types of single-machine scheduling problems: the total weighted earliness-tardiness problem with equal (zero) release dates, that with distinct release dates, the total weighted completion time problem with distinct release dates, and the total weighted tardiness problem with distinct release dates. Computational experiments demonstrate that our algorithm outperforms existing exact algorithms and can solve instances of the first three problems with up to 200 jobs and those of the last problem with up to 80 jobs.     

金属蒸气法制备聚合物固载Pd－Cu双金属原子簇

为了不使用任何还原剂而获得聚合物固载高分散零价双金属加氢催化剂，利用金属蒸气法制备了３种不同Ｐｄ／Ｃｕ质量比的聚合物固载双金属原子簇。透射电镜（ＴＥＭ）和Ｘ衍射（ＸＲＤ）测定表明，Ｐｄ－Ｃｕ原子簇粒度很小，平均直径小于３．０ｎｍ。Ｘ射线光电子能谱（ＸＰＳ）表明，Ｐｄ和Ｃｕ均为零价态。Ｐｄ－Ｃｕ原子簇在异丙叉加氢反应中具有很高的活性和选择性。这些结果提供了令人信服的证据，即金属蒸气法可用于在聚合物孔穴内直接而温和地置入小的零价金属原子簇，而且这样制备的聚合物固载金属原子簇很适合于催化应用。     

我国卫星测控系统发展概况及几点建议

本文介绍了我国国内C频段、国际C频段两个卫星测控网站,三代典型微波统一测控系统的特点,提出了对新型航天测控设备研制的建议。     

Permeability of vitamin B-12 in chitosan membranes. Effect of crosslinking and blending with poly(vinyl alcohol) on permeability

The permeability and diffusion of vitamin B-12 in chitosan, crosslinked chitosans, and chitosan/poly(vinyl alcohol) (PVA) blends were studied using “lag time” technique. Apparently the diffusion coefficient, D, for both crosslinked and blended chitosan membranes depends solely upon the equilibrium swelling ratio, Q, of the material in water. The functional dependence of D on Q was obtained from the data. The partition coefficients calculated for vitamin B-12 in all membranes studied were nearly constant (K ≈ 0.4). The results are shown to be consistent with the “pore type” transport mechanism for vitamin B-12 in these chitosan membranes.     

酞花菁气体传感器

叙述了酞化菁及金属络合物的气敏特性,气敏机理以及存在的问题和发展趋向     

An explicit application of partition of unity approach to XFEM approximation for precise reproduction of a priori knowledge of solution

The application of the XFEM to fracture mechanics is effective, because a crack can be modeled independently from the meshes and a complex remeshing procedure can be avoided. However, the classical XFEM has an essential problem in the approximation of partially enriched elements, that is, blending elements, which causes a lack of accuracy. For the weighted XFEM, although the numerical results show the effective improvements, it was found that the issue of blending elements still remains upon detailed examination. In the present paper, the PU‐XFEM is formulated as an explicit application of the partition of unity (PU) approach to the XFEM, in order to precisely reproduce a priori knowledge of the solution by enrichment. The PU‐XFEM is applied to two‐dimensional linear fracture mechanics, and its effectiveness is verified. It is consequently found out that the PU‐XFEM precisely reproduces a priori knowledge of the solution and is therefore effective to completely solve the problem of the blending elements. Copyright © 2013 John Wiley & Sons, Ltd.     

帘线钢表面氧化优化工艺及控制机理研究

采用OM和SEM分析方法研究了帘线钢空气气氛下连续氧化行为以及高线精轧、吐丝温度对热轧盘条表面氧化铁皮厚度和相组成的影响,同时采用热模拟方法分析了FeO层发生先共析、共析转变生成Fe3O4的条件.实验结果表明,945℃是帘线钢快速氧化起点温度,随着温度升高,氧化速率急剧增加;而当温度降低到700℃时,氧化过程极其缓慢.控制700~945℃范围内的冷速是控制氧化铁皮厚度及相组成的关键工艺.高线生产控制精轧和吐丝温度在900~940℃,氧化铁皮厚度7~20μm,FeO质量分数为65%~80%,具有最佳除鳞性能.热模拟分析表明,400~500℃是FeO层发生共析转变的"鼻尖"温度,孕育期最短.提高400~500℃区间冷速可抑制FeO层发生共析转变,使机械除鳞率提高3%左右.     

950 keV, 3.95 MeV and 6 MeV X-band linacs for nondestructive evaluation and medicine

We are developing compact X-band linac X-ray sources for nondestructive evaluation and medicine. First, we develop a portable X-ray system by a 950 keV 9.4 GHz X-band linac to realize on-site inspection. We use a low power (250 kW) magnetron as an RF source for compactness of the whole system. Since the RF power source is quite small and the stored energy in the structure is also small, we faced the problem of beam loading and current/RF-power oscillation. We are analyzing the problem by the circuit model. We plan to use this system for erosion inspection of metal pipes of petrochemical complex. By adopting a side-coupling cavity design to avoid the oscillation, we have developed 6 MeV X-band (9.3 GHz) linac for pinpoint dynamic tracking cancer therapy. Furthermore, we are manufacturing 3.95 MeV X-band (9.3 GHz) linac X-ray source with flexible waveguides for on-site bridge inspection. Updated results and situations are presented.