6.304不锈钢薄壁管生产过程中残余应力的计算与消除

在304不锈钢薄壁管的生产过程中,对温度和残余应力进行了数值计算和实测。采用FDM法分析所得的温度与采用热电偶和温度仪所测得的温度完全一致,这说明用计算所得的温度分布来进行应力分析是可行的。对钨极惰性气体保护(TIG)电弧焊接和空气冷却后的残余应力计算,轴向单元FEM应力简化分析法也是行之有效的。X射线衍射法所测得的应力也同计算值基本一致。这就清楚地表明,甚至在定径后,仍然存在有超过300 MPa的残余拉应力。文中提出的两种消除应力的方法,即采用轴向延伸和周向压力变形,能使轴向和周向残余应力大幅度减少到100MPa以下。

Basic design of beamline and polarization control

The basic concept of synchrotron radiation beamlines for vacuum ultraviolet and X-ray experiments has been introduced to beginning users and designers of beamlines. The beamline defined here is composed of a front end, pre-mirrors, and a monochromator with refocusing mirrors, which are connected by beam pipes, providing monochromatic light for the experiments. Firstly, time characteristics of the synchrotron radiation are briefly reviewed. Secondly, the basic technology is introduced as the fundamental knowledge required to both users and designers. The topics are photoabsorption by air and solids, front ends and beam pipes, mirrors, monochromators, and filters. Thirdly, the design consideration is described mainly for the designers. The topics are design principle, principle of ray tracing, optical machinery and control, and vacuum. Fourthly, polarization control is considered. The topics are polarizers, polarization diagnosis of beamline, and circularly-polarized light generation. Finally, a brief summary is given introducing some references for further knowledge of the users and the designers.

Schwarzschild microscopes in vacuum ultraviolet and soft X-ray regions

Microscopes in vacuum ultraviolet and soft X-ray regions using a normal incidence type of Schwarzschild objective are reviewed. The objective consists of a concave mirror and a convex mirror coated with a high reflectance multilayer,having a large numerical aperture comparing with other objectives. The microscopes have been used to diagnose inertia-confinement-fusion plasmas,and to investigate small samples or microstructures of in- organic and organic materials by imaging them using laboratory light sources. Synchrotron radiation has been also used to obtain a microbeam for a photoelectron scanning microscope with a spatial resolution of 0.1 μm. The struc- ture and performance of two laboratory microscopes developed at Tohoku University are demonstrated. One of them is a soft X-ray emission imaging microscope. An image of an artificial pattern made of W and SiO2 on Si wafer by focusing Si L emission was presented. The other is an ultraviolet photoelectron scanning microscope using a He (he- lium) gas discharge lamp. The valence band spectra of a microcrystal of FeWO4 were presented. Furthermore other applications such as demagnifying optics for lithography and optics to gather fluorescence for emission spectroscopy are introduced.

ICRF Experiments and Potential Formation on the GAMMA 10 Tandem Mirror

Target plasmas, on which the formation of the electrostatic potentials and the improvement of the confinement are studied, are produced with ICRF in the GAMMA 10 tandem mirror. The ion temperature of more than 10 keV has been achieved in relatively low density plasmas. When the strong ICRF heating is applied, it is observed that the high frequency and the low frequency fluctuations are excited and suppress the increase of the plasma parameters. Recently, a new high power gyrotron system has been constructed and the ECRH power in plug extends up to 370 kW. The improvement of the confinement due to the formation of the potential in the axial direction and the strong radial electric field shear has been observed.

探求高亮度器件是LED技术发展的核心

LED 技术发展的首要任务是提高亮度。为了开发高亮度和超高亮度 LED,红色 LED 芯片取材正从传统的 GaAsP 和 GaP 转向 GaAlAs。第一支可见光 LED(发光二极管)是美国蒙桑托(Monsanto)公司1968年开发的。这是一种 GaAsP 化合物半导体管,发射红色光。自那以后,对化合物半导体 LED 做了深入细致的研究和开发工作,至今高亮度及多色 LED 已经见诸市场。

添加物对NdFeB磁体的影响

用抑制掺杂法研究了添加物对NdFeB磁体的影响,发现诸如Cr_2O_3、Y_2O_3、V_2O_5,Al_2O_3和其它一些添加物,可改进NdFeB磁体的抗腐蚀能力和退磁曲线的方形度。某些添加物可有效地增加矫顽力。

Measurement of the integrated luminosity of the Phase 2 data of the Belle Ⅱ experiment

From April to July 2018,a data sample at the peak energy of the T(4 S) resonance was collected with the Belle Ⅱ detector at the SuperKEKB electron-positron collider.This is the first data sample of the Belle Ⅱ experiment.Using Bhabha and digamma events,we measure the integrated luminosity of the data sample to be(496.3±0.3±3.0) pb-1,where the first uncertainty is statistical and the second is systematic.This work provides a basis for future luminosity measurements at Belle Ⅱ.

Performance of Ion-gel Actuator Containing Ionic Liquids

1 Results Electroactive polymers (EAPs) driven by transducing electric energy into mechanical energy have been the subjects of recent interest[1]."Ionic liquids",consisting entirely of cation and anion,have characteristic features such as negligible volatility,non-flammability,thermal and chemical stability,and high ionic conductivity.We proposed an EAP actuator utilizing ion-gels[2-3],which consist of ionic liquids and polymers,sandwiching with two carbon material sheets as shown in Fig.1.This electrol...