Multifrequency channel microwave reflectometer with frequency hopping operation for density fluctuation measurements in Large Helical Device

In order to measure the internal structure of density fluctuations using a microwave reflectometer, the broadband frequency tunable system, which has the ability of fast and stable hopping operation, has been improved in the Large Helical Device. Simultaneous multipoint measurement is the key issue of this development. For accurate phase measurement, the system utilizes a single sideband modulation technique. Currently, a dual channel heterodyne frequency hopping reflectometer system has been constructed and applied to the Alfve?n eigenmode measurements.     

Two-dimensional measurement of edge impurity emissions using space-resolved extreme ultraviolet spectrometer in Large Helical Device

A space-resolved extreme ultraviolet (EUV) spectrometer working in wavelength range of 50-500 A? has been developed to measure two-dimensional distribution of impurity spectral lines emitted from edge plasma of Large Helical Device (LHD), in which the magnetic field is formed by stochastic magnetic field with three-dimensional structure called ergodic layer. The two-dimensional measurement of edge impurity line emissions is carried out by scanning horizontally the observation chord of the space-resolved EUV spectrometer during single LHD discharge. Images of CIV (312.4 A?) and HeII (303.78 A?) are presented as the first result. The results are compared with ones calculated from the edge chord length in the ergodic layer of LHD plasma.     

Absolute intensity calibration of flat-field space-resolved extreme ultraviolet spectrometer using radial profiles of visible and extreme ultraviolet bremsstrahlung continuum emitted from high-density plasmas in Large Helical Device

A precise absolute intensity calibration of a flat-field space-resolved extreme ultraviolet (EUV) spectrometer working in wavelength range of 60-400 ? is carried out using a new calibration technique based on radial profile measurement of the bremsstrahlung continuum in Large Helical Device. A peaked vertical profile of the EUV bremsstrahlung continuum has been successfully observed in high-density plasmas (n(e) ≥ 10(14) cm(-3)) with hydrogen ice pellet injection. The absolute calibration can be done by comparing the EUV bremsstrahlung profile with the visible bremsstrahlung profile of which the absolute value has been already calibrated using a standard lamp. The line-integrated profile of measured visible bremsstrahlung continuum is firstly converted into the local emissivity profile by considering a magnetic surface distortion due to the plasma pressure, and the local emissivity profile of EUV bremsstrahlung is secondly calculated by taking into account the electron temperature profile and free-free gaunt factor. The line-integrated profile of the EUV bremsstrahlung continuum is finally calculated from the local emissivity profile in order to compare with measured EUV bremsstrahlung profile. The absolute intensity calibration can be done by comparing measured and calculated EUV bremsstrahlung profiles. The calibration factor is thus obtained as a function of wavelength with excellent accuracy. It is also found in the profile analysis that the grating reflectivity of EUV emissions is constant along the direction perpendicular to the wavelength dispersion. Uncertainties on the calibration factor determined with the present method are discussed including charge-coupled device operation modes.     

Poloidal beam emission spectroscopy system for the measurement of density fluctuations in Large Helical Device

A system of beam emission spectroscopy (BES) for density fluctuation measurements having the sightlines passing through the plasma in the poloidal direction was developed in the Large Helical Device (LHD). Even though the angle between the beam and the sightline is slightly larger than a right angle, Doppler-shifted beam emission can be distinguished from background emission because of the high energy (120-170 keV) of the neutral beam for heating with negative ion sources. Spatial resolution is about 0.1-0.2 in the normalized radius. Compared with the prototype BES system with toroidal sightlines, the BES system with poloidal sightlines showed improved spatial resolution.     

一种分度式主动螺旋管道测量装置设计

ILI(in-line inspection)管道在线检测对油气输送管道安全可靠运行至关重要。设计开发了一种全新的基于螺旋测量原理的主动螺旋管道测量装置,该装置能够自主生成管道测量螺旋线,整合了位移传感器和角度传感器,进行了管道测量对比实验以及管道缺陷检测实验;实验数据采用MATLAB处理,反演出管道内壁模型,通过对管道内壁模型的分析来判断管道内部的情况。实验证明了分度式主动螺旋测量方法的可行性,通过对比实验分析了分度式螺旋测量与普通螺旋测量的区别,实验结果表明:该方法描述管道内壁的三维模型更精确,能被管道机器人或管道猪牵引进行测量作业。特别对于微小管径管道、非管道猪管道有一定的应用前景。     

Fusion product diagnostics planned for Large Helical Device deuterium experiment

Deuterium experiment on the Large Helical Device (LHD) is now being planned at the National Institute for Fusion Science. The fusion product diagnostics systems currently considered for installation on LHD are described in this paper. The systems will include a time-resolved neutron yield monitor based on neutron gas counters, a time-integrated neutron yield monitor based on activation techniques, a multicollimator scintillation detector array for diagnosing spatial distribution of neutron emission rate, 2.5 MeV neutron spectrometer, 14 MeV neutron counter, and prompt γ-ray diagnostics.     

Development of electron cyclotron emission imaging system on Large Helical Device

A combined system of microwave imaging reflectometry and electron cyclotron emission (ECE) imaging has been developed for the Large Helical Device. This system includes a wide-band two-dimensional horn-antenna mixer array (HMA). The HMA consists of horn antennas, waveguides, mixers, and intermediate frequency circuits. The frequency response of the HMA is between 50 and 110 GHz. The ECE signal is selected using a 95 GHz local oscillator and a 93 GHz high-pass filter.     

螺旋叶片卷制方法

针对螺旋输送机上的螺旋叶片放样难题,介绍了一种螺旋叶片卷制新方法并设计了新型螺旋叶片卷制专用机床,可直接卷制成型,具有材料消耗低、生产效率高、可连续运转等优点。     

博世力士乐投资2.8亿新建北京、常州工厂

继今年4月上海金桥工厂建成运营后。全球领先的工业技术供应商博世力士乐近日宣布，其投资1．85亿元人民币新建的北京工厂和投资9500万元人民币扩建的常州新工厂正式落成，将进一步拓展其在中国的业务。     

Electrical test method using high density plasmas for high-end printed circuit boards

A novel electrical test method that uses high-density plasmas, such as inductively coupled discharges, is proposed to detect open/short failures of high-end printed circuit boards (PCBs). The PCB is inserted into the plasma chamber with the top side facing the plasma sheath, and the bottom of the PCB is connected to the probe pin for the dc voltage bias and current measurements. A failure, including a latent open, can be precisely detected by biasing the dc voltage near the plasma potential due to the specific characteristics of the sheath formed on the PCB surface.     

Relatively scaled ECE temperature profiles of KSTAR plasmas

A scheme to obtain relatively scaled profiles of electron cyclotron emission (ECE) temperature directly from uncalibrated raw radiometer data is proposed and has been tested for the 2009 campaign KSTAR plasmas. The proposed method utilizes a position controlled system to move the plasma adiabatically and compares ECE radiometer channels at the same relative radial positions assuming the profile consistency during the adiabatic change. This scaling method is an alternative solution when an absolute calibration is unreliable or too time consuming. The application to the two dimensional ECE imaging data, wherein calibration is extremely difficult, may also prove to be useful.     

Simultaneous projection and detection system of four different frequencies for microwave imaging reflectometry in Large Helical Device

A simultaneous projection/detection system of four different frequencies for microwave imaging reflectometry (MIR) was developed for three-dimensional observation of electron density fluctuations in the Large Helical Device (LHD). The microwave with four frequency components at 60.410, 61.808, 63.008, and 64.610 GHz is projected in a continuous-wave mode to illuminate the target LHD plasma. A two-dimensional horn-antenna mixer array (2D HMA) receives the reflected wave from the plasma as well as the wave from the local oscillator operating at 55.800 GHz. The first intermediate frequency (IF) signals at 4.610, 6.008, 7.208, and 8.810 GHz were confirmed to be obtained by downconversion of these microwaves using the 2D HMA. Each of these first IF components is filtered from each other and downconverted again for the superheterodyne detection. It was confirmed that both the amplitudes and the phases of the detected signals reflect the fluctuations in LHD plasmas.     

Measurements of neutral helium density in helicon plasmas

Laser-induced-fluorescence (LIF) is used to measure the density of helium atoms in a helicon plasma source. For a pump wavelength of 587.725 nm (vacuum) and laser injection along the magnetic field, the LIF signal exhibits a signal decrease at the Doppler shifted central wavelength. The drop in signal results from the finite optical depth of the plasma and the magnitude of the decrease is proportional to the density of excited state neutral atoms. Using Langmuir probe measurements of plasma density and electron temperature and a collisional-radiative model, the absolute ground state neutral density is calculated from the optical depth measurements. Optimal plasma performance, i.e., the largest neutral depletion on the axis of the system, is observed for antenna frequencies of 13.0 and 13.5 MHz and magnetic field strengths of 550-600 G.     

Layout and results from the initial operation of the high-resolution x-ray imaging crystal spectrometer on the Large Helical Device

First results of ion and electron temperature profile measurements from the x-ray imaging crystal spectrometer (XICS) diagnostic on the Large Helical Device (LHD) are presented. This diagnostic system has been operational since the beginning of the 2011 LHD experimental campaign and is the first application of the XICS diagnostic technique to helical plasma geometry. The XICS diagnostic provides measurements of ion and electron temperature profiles in LHD with a spatial resolution of 2 cm and a maximum time resolution of 5 ms (typically 20 ms). Ion temperature profiles from the XICS diagnostic are possible under conditions where charge exchange recombination spectroscopy (CXRS) is not possible (high density) or is perturbative to the plasma (low density or radio frequency heated plasmas). Measurements are made by using a spherically bent crystal to provide a spectrally resolved 1D image of the plasma from line integrated emission of helium-like Ar(16 +). The final hardware design and configuration are detailed along with the calibration procedures. Line-integrated ion and electron temperature measurements are presented, and the measurement accuracy is discussed. Finally central temperature measurements from the XICS system are compared to measurements from the Thomson scattering and CXRS systems, showing excellent agreement.     

一种轻便高效的大直径回转支承滚道直径测量装置

研制一种新的测量大型回转支承滚道直径的检测装置.运用弓高弦长测量方法测量,用光栅精确检测弓高数据,通过显示器对测量结果实现数字输出.该装置可以实现用小装置测量大直径.文中介绍了其工作原理、结构组成等,并对该检测装置进行了误差分析.结果表明,该检测装置具有较高的检测精度.     

Measurement of velocity profiles in multiphase flow using a multi-electrode electromagnetic flow meter

This paper describes an electromagnetic flow meter for velocity profile measurement in single phase and multiphase flows with non-uniform axial velocity profiles. A Helmholtz coil is used to produce a near-uniform magnetic field orthogonal to both the flow direction and the plane of an electrode array mounted on the internal surface of a non-conducting pipe wall. Induced voltages acquired from the electrode array are related to the flow velocity distribution via variables known as ‘weight values’ which are calculated using finite element software. Matrix inversion is used to calculate the velocity distribution in the flow cross section from the induced voltages measured at the electrode array. This paper presents simulations and experimental results including, firstly the effects of the velocity profile on the electrical potential distribution, secondly the induced voltage distribution at the electrode pair locations, and thirdly the reconstructed velocity profile calculated using the weight values and the matrix inversion method mentioned above. The flow pipe cross-section is divided into a number of pixels and, in the simulations, the mean flow velocity in each of the pixels in single phase flow is calculated from the measured induced voltages. Reference velocity profiles that have been investigated in the simulations include a uniform velocity profile and a linear velocity profile. The results show good agreement between the reconstructed and reference velocity profiles. Experimental results are also presented for the reconstructed velocity profile of the continuous water phase in an inclined solids-in-water multiphase flow for which the axial water velocity distribution is highly non-uniform. The results presented in this paper are most relevant to flows in which variations in the axial flow velocity occur principally in a single direction.     

大螺旋角齿条刀的线切割加工工艺

齿条刀是典型的多角度刀具，在平置加工时其角度参数超出了线切割机床上下异形角度加工极限。通过改变加工时的安装角度和合理编制加工程序，可取得线切割加工齿条刀的良好效果。本文举出加工实例，说明了具体实施方法及加工要点。     

Direct detection of lower hybrid wave using a reflectometer on Alcator C-Mod

The possibility of directly detecting a density perturbation produced by lower hybrid (LH) waves using a reflectometer is presented. We investigate the microwave scattering of reflectometer probe beams by a model density fluctuation produced by short wavelength LH waves in an Alcator C-Mod experimental condition. In the O-mode case, the maximum response of phase measurement is found to occur when the density perturbation is approximately centimeters in front of the antenna, where Bragg scattering condition is satisfied. In the X-mode case, the phase measurement is predicted to be more sensitive to the density fluctuation close to the cut-off layer. A feasibility test was carried out using a 50 GHz O-mode reflectometer on the Alcator C-Mod tokamak, and positive results including the detection of 4.6 GHz pump wave and parametric decay instabilities were obtained.