Creep rupture behaviour of circumferentially welded mod. 9Cr–1Mo steel pipe subject to internal pressure and axial load

The multi-axial creep strength of circumferential welds in power piping, including failure mode and failure life against a wide range of stress ratios and stress levels, was newly examined in this paper. The creep rupture behaviour of modified 9Cr–1Mo steel (9Cr–1Mo–VNb steel; ASME P91) pipe with a circumferential weld subject to combined internal pressure and axial load was experimentally investigated at 650 °C. The test results, with several kinds of stress ratios of macroscopic axial and hoop stress can be summarised as follows. Along with the increased stress ratio (axial/hoop), both failure location and failure mode changed from a base metal failure caused by hoop stress to an FGHAZ (fine-grained heat affected zone) failure due to axial stress. The stress ratio where the failure mode changed was ‘0.8’. Strength reduction in FGHAZ failure by axial stress should be considered in the structural design of circumferential welds. A series of FEM creep analysis was carried out to discuss the relation of the failure mode to both the local stress distribution and the damage. The failure mode variation along with the increase in the stress ratio is also discussed based on simplified ductile creep failure analysis.     

TRD工法在复杂地层中的应用

TRD工法（混合搅拌壁式地下连续墙施工方法）在武汉市长航中心大厦基坑试成墙过程中发生切割箱向面外变形及多次链条脱落等情况,经过对浅部杂填土的处理、施工方法和切割刀排配置的改进,解决了复杂地层和超深水泥土连续墙的成墙问题,为后续工程的完成打好了基层,可为类似工程提供参考.     

Multi-scale analysis of AFM tip and surface interactions

Thoroughly understanding AFM tip-surface interactions is crucial for many experimental studies and applications. It is important to realize that despite its simple appearance, the system of tip and sample surface involves multiscale interactions. In fact, the system is governed by a combination of molecular force (like the van der Waals force), its macroscopic representations (such as surface force) and gravitational force (a macroscopic force). Hence, in the system, various length scales are operative, from sub-nanoscale (at the molecular level) to the macroscopic scale. By integrating molecular forces into continuum equations, we performed a multiscale analysis and revealed the nonlocality effect between a tip and a rough solid surface and the mechanism governing liquid surface deformation and jumping. The results have several significant implications for practical applications. For instance, nonlocality may affect the measurement accuracy of surface morphology. At the critical state of liquid surface jump, the ratio of the gap between a tip and a liquid dome (δ) over the dome height (y₀) is approximately (n-4) (for a large tip), which depends on the power law exponent n of the molecular interaction energy. These findings demonstrate that the multiscale analysis is not only useful but also necessary in the understanding of practical phenomena involving molecular forces.     

Highly conductive SnO2 thin films for flat‐panel displays

Abstract— SnO₂ is considered to be a promising alternative material for indium tin oxide (ITO), which is used for thin‐film transparent electrodes in flat‐panel displays (FPDs) and is facing a serious indium depletion problem. However, annealing processes in the manufacture of plasma‐display panels (PDPs), which are major FPDs, cause high resistivity in SnO₂ films. To obtain lower resistivity after the annealing processes, the relationship between deposition conditions and resistivity and the influences of annealing on resistivity, both theoretically and experimentally, were investigated. As a solution, a method involving the formation of a coating of SiO₂ on SnO₂ is proposed, and a SnO₂ resistivity as low as 6.60 × 10^?5 Ω‐m was obtained after annealing.     

Thermoelectric Properties of p-Type Mg2Si0.25Sn0.75 Doped with Sodium Acetate and Metallic Sodium

We have investigated the thermoelectric properties of p-type Na-doped Mg₂ Si_0.25Sn_0.75 solid solutions prepared by liquid–solid reaction and hot-pressing methods. Na was introduced into Mg₂Si_0.25Sn_0.75 by using either sodium acetate (CH₃COONa) or metallic sodium (2 N). The samples doped with sodium acetate consisted of phases with antifluorite structure and a small amount of MgO as revealed by x-ray diffraction, whereas the sample doped with metallic sodium contained the Sn, MgO, and Mg₂SiSn phases. The hole concentrations of Mg_1.975Na_0.025Si_0.25Sn_0.75 doped by sodium acetate and metallic sodium were 1.84 × 10²⁵ m^?3 and 1.22 × 10²⁵ m^?3, respectively, resulting in resistivities of 4.96 × 10^?5 Ω m (sodium acetate) and 1.09 × 10^?5 Ω m (metallic sodium). The Seebeck coefficients were 198 μV K^?1 (sodium acetate) and 241 μV K^?1 (metallic sodium). The figures of merit for Mg_1.975Na_0.025Si_0.25Sn_0.75 were 0.40 × 10^?3 K^?1 (sodium acetate) and 0.25 × 10^?3 K^?1 (metallic sodium) at 400 K. Thus, sodium acetate is a suitable Na dopant for Mg₂Si_1?x Sn _x .     

Enhancement of the actuation performance of dielectric triblock copolymers modified with additives

To enhance actuation performance without prestrain, an elastomeric acrylic triblock copolymer, poly(methyl methacrylate)‐block‐poly(n‐butyl acrylate)‐block‐poly(methyl methacrylate), was modified with two kinds of additives, oligomeric poly(n‐butyl acrylate) and the plasticizer dibutyl sebacate. An actuator modified with those additives showed about 6% strain, whereas the unmodified actuator showed only 1% strain for the same applied electric field without prestrain. In addition, actuation was attained at lower critical electric field strength (625 and 1000 V mm^?1 for modified and unmodified actuators, respectively). Upon increasing the amounts of the additives, the electrically induced actuation velocity and degree of deformation increased. These results are explained by the dielectric and mechanical properties of the elastomers. The dielectric constants for elastomers modified with dibutyl sebacate were larger than those for elastomers modified with oligomeric poly(n‐butyl acrylate). The initial tensile stresses of both of the modified elastomers were much smaller than that of unmodified elastomer. The results provide a route to enhancing actuation performance of dielectric elastomers without prestrain. Copyright © 2011 Society of Chemical Industry     

Reaction of sodium perborate with a chlorinated cyclic hindered amine (N-chloro-4-hydroxy-2,2,6,6-tetramethylpiperidine) II. Activating effects and related characteristics in practical fabric bleaching

A synergetic bleaching activation phenomenon of the chlorinated cyclic hindered amine, N-chloro-4-hydroxy-2,2,6,6-tetramethylpiperidine (TMP-Cl) on sodium perborate (PB) was examined under some practically applicable bleaching procedures. By combining TMP-Cl with PB, the bleaching effect toward black tea, fruit juices and other stains was enhanced synergetically, achieving an efficiency similar to that of the well-known tetraacetylethylenediamine/PB system. However, behavior observed in the TMP-Cl/PB system, such as high bleaching efficiency in an alkaline range, superior durability for repeated bleaching, less discoloration of cloth that contains reactive dyes and no influence on the activity of an enzyme, was favorable for a bleaching component of heavy-duty detergents.     

A 70 nm 16 Gb 16-Level-Cell NAND flash Memory

A 16 Gb 16-level-cell (16LC) NAND flash memory using 70 nm design rule has been developed . This 16LC NAND flash memory can store 4 bits in a cell which enabled double bit density comparing to 4-level-cell (4LC) NAND flash, and quadruple bit density comparing to single-bit (SLC) NAND flash memory with the same design rule. New programming method suppresses the floating gate coupling effect and enabled the narrow distribution for 16LC. The cache-program function can be achievable without any additional latches. Optimization of programming sequence achieves 0.62 MB/s programming throughput. This 16-level NAND flash memory technology reduces the cost per bit and improves the memory density even more.     

Development of a Continuous Desiliconization Process in the Hot Metal Runner of a Blast Furnace

An efficient continuous desiliconization process equipped with a mechanical stirrer in a hot metal runner was newly developed. The facility was installed during the revamping of No.3 blast furnace at Kobe Works, and the commercial operation started up successfully in January 2008. Before the installation of the commercial facility, the reaction behaviour was investigated under various experimental conditions for the application of a mechanical stirring method to continuous desiliconization treatment in the hot metal runner. Hot metal experiments at laboratory scale showed that the stirring intensity was an important factor for the process performance, and the mechanical stirring method was available for the improvement of reaction efficiency. As a result of plant tests, it was confirmed that a higher oxygen efficiency of desiliconization was achieved by the combination of runner arrangement and mechanical stirrer compared with the conventional injection of the desiliconizing agent. According to the reaction analysis of continuous desiliconization in the hot metal runner using the semi‐batch reaction model, it was estimated that the average slag‐metal residence time in the reaction region is improved due to an increased entrainment of foamed slag into the stirred metal bath in the mechanical stirring method, and therefore, it leads to a high desiliconization efficiency. Based on the experimental results, the equipment specifications and the runner design for this process were determined.     

Observation of the internal waveforms in high-speed high-density LSIs using an EOS prober

Electron beam (EB) probing has been used to observe the internal waveforms in ULSLs. However, as the speed of LSIs increases and their power consumption decreases, the temporal and voltage resolution of EB probing is going to be inadequate for measuring these waveforms. Electro-optic sampling (EOS) probing is expected to overcome this limitation, provided its spatial resolution can be improved. In this paper, forming a via on the interconnection under test is proposed for practically improving spatial resolution. The effectiveness of this method and the dependence of the detected signal level on testing pad area are clarified by simulation. To verify these results, vias are formed in ECL SRAMs by focused ion beam trimming, and waveforms with frequency as high as 100 MHz and swing as small as 30 mV are successfully observed. Using this technique, the dependence of the detected signal level on testing pad area is verified, and it is confirmed that the amplitude change below 10 mV and the delay time below 100 ps can be measured. With the improved spatial resolution, EOS probing enables us to observe high-frequency and small-swing waveforms even in high-density fine interconnections. In future, this technology will be crucial for observing internal waveforms in LSIs.