Mutual Inductance of a Precise Rogowski Coil in Dependence of the Position of Primary Conductor

The Rogowski coil is a well-known current-to-voltage transducer. To use it for the high-accuracy measurement of ac current (at power supply frequency), all influencing quantities and their contribution should be recognized and analyzed. Thus, the partial influence due to the deviation from the central position of the primary conductor for a real sensor, with the nonhomogeneous density of secondary turns, is given in this paper. The measured deviation of mutual inductance in this case showed very good agreement with the theoretical prediction, which is promising for the expected application of such a sensor.      

Development of Thermal Kinetic Inductance Detectors Suitable for X-ray Spectroscopy

We report on the development of thermal kinetic inductance detectors (TKIDs) suitable to perform X-ray spectroscopy measurements. The aim is to implement MKIDs sensors working in thermal quasi-equilibrium mode to detect X-ray photons as pure calorimeters. The thermal mode is a variation on the MKID classical way of operation that has generated interest in recent years. TKIDs can offer the MKIDs inherent multiplexibility in the frequency domain, a high spatial resolution comparable with CCDs, and an energy resolution theoretically limited only by thermodynamic fluctuations across the thermal weak links. Microresonators are built in Ti/TiN multilayer technology with the inductive part thermally coupled with a metal absorber on a suspended SiN membrane, to avoid escape of phonons from the film to the substrate. The mid-term goal is to optimize the single-pixel design in terms of superconducting critical temperatures, internal quality factors, kinetic inductance and spectral energy resolution. The final goal is to realize a demonstrator array for a next generation thousand pixels X-ray spectrometer. In this contribution, the status of the project after one year of developments is reported, with detailed reference to the microresonators design and simulations and to the fabrication process.     

铝阳极氧化膜渗透性的电化学阻抗法分析

电化学阻抗谱(EIS)是研究氧化膜渗透性能的有效技术,据此,对磷酸介质中制备的氧化膜在H2O/H2O,0.1 mol/L NaCl/H2O,0.1 mol/,L NaCl/0.1 mol//L NaCl体系及0.1 mol/,L NaCl/H2O体系中不同渗透时间的电化学阻抗谱进行了初步探讨.结果袁明:所设计的铝阳极氧化膜渗透的实际体系可以用(RC)R(QR)R(RC)等效电路来表示;交流阻抗技术可以对磷酸介质中多孔氧化膜的渗透性进行定性分析;在NaCl/H2O体系中,多孔氧化膜的Nyquist谱是典型的Warburg阻抗谱,有明显的扩散特征,这种特征与氧化膜的渗透性紧密相关;在Bode谱高频区,随着渗透时间的增加,氧化膜的阻抗值呈减小趋势,但下降幅度有限,扩散渗透量很小.     

Unusual Electronic State of Layered θ-(ET)2 X Studied by Raman Spectroscopy

Employing Raman spectroscopy, we have studied the electronic structure of the charge-ordering system, θ−(ET)₂X, the dihedral angle (φ) of which ranges from 100 to 121°. The most stable metal, θ−(ET)₂I₃, (φ=100°) has a uniform charge distribution in a whole temperature range. The compounds with φ > 111° have an inhomogeneous charge distribution even above the CO transition, which implies that the charges have localized nature in a whole temperature range. These localized charges are long-range ordered in the CO phase, whereas they are fluctuating randomly or forming short-range ordered domains above the CO phase transition.     

The Influence of Temperature Distribution on YBCO Coated Conductor Deposited by Reel-to-Reel PLD Method

It is known that the tape’s temperature controlled by a close substrate heater will still deviate after the deposition process. In this work, we deposited YBa₂Cu₃O_7−δ (YBCO) films on RABiTS substrates with multilayer CeO₂/YSZ/CeO₂ buffer layers by pulsed laser deposition (PLD) under a different distribution of temperature deviation in order to improve it. Thermocouples were applied to exactly measure the temperature. X-ray diffraction (XRD) and scanning electron microscopy (SEM) were used to inspect c-axis oriented crystals and surface morphology of YBCO films. Through this work, we found that the even shape is best. Under the temperature deviation with the best shape, a transport J _c of 3.2×10⁶ A/cm² and I _c =240 A was obtained for a 0.75 μm thick YBCO film on CeO₂/YSZ/CeO₂-bufferd RABiTS Ni–W alloy.     

Moisture Distribution in Partially Saturated Concrete Studied by Impedance Spectroscopy

The moisture content and its spatial distribution has a great influence on the durability properties of concrete structures. Several non-destructive techniques have been used for the determination of the total water content, but moisture distribution is difficult to determine. In this paper impedance spectroscopy is used to study the water distribution in concrete samples with controlled and homogeneously distributed moisture contents. The technique is suitable for the determination of water distribution inside the sample, using the appropriate equivalent circuits. It is shown that using the selected drying procedures there is no change in the solid phase of the samples, although the technique can only be used for the qualitative study of variations in the solid phase when samples are too thick. The results of this work show that for a wide range of concrete percentages of saturation, from full to 18 % saturation, practically all the pores keep at least a thin layer of electrolyte covering their walls, since the capacitance measurement results are practically independent of the saturation degree.     

Identifying the Permeability Field of a Three-Dimensional Layered Bed with Allowance for a Priori Information on Wells under Steady-State Single-Phase Filtration Conditions

Journal of Engineering Physics and Thermophysics - Consideration is given to the coefficient problem on determining the permeability field of a three-dimensional layered bed under the conditions of...     

Simulation of the Heating of a Tungsten Conductor by a Nanosecond High-Power Current Pulse

The initial stage of explosion of a thin tungsten wire by a high-power current pulse of nanosecond duration is simulated. Radial distributions of parameters of matter are obtained for two models. According to one of the models, it is assumed that an instantaneous separation into phases occurs if the parameters of metal have reached values corresponding to the binodal; in the other model, the existence of a metastable state is allowed. Phase trajectories in the P–Tand –Tplanes are given.     

生物矿化法制备平片状 YBCO 粉末及导体

介绍了一种全新的制备YBCO超导粉末的方法,通过加入右旋糖酐采用生物矿化的方法,可以使制备的 YBCO 粉末晶粒均呈现出平片状,其典型尺寸为5μm ×5μm ×1μm, TEM显示这些平片状晶粒本身亦呈现层片状结构。同时在一定的区域内,这些平片状YBCO晶粒会自发聚集形成具有相似生长方向的晶粒簇。在这些晶粒簇内部首次在 YBCO内部发现存在有自发超导连接现象。超导连接区域平均包含3～5个平片状晶粒。由于这种YBCO粉末具有特殊的微观结构,所以具有很好的超导性能,其Jc 值在77 K自场下达到了0.1 MA· cm -2,比同等条件下的商业 YBCO 粉末高出10倍以上。用这种具有特殊结构的YBCO粉末可以制备出可以实际承载超导传输电流的 YBCO导体,结果表明此方法有望成为一条全新且廉价又高效的制备YBCO导体的新路线。     

Inductance calculation of twisted conductors by the broken line approximation

The mutual inductance between two skew straight thin conductors is obtained as a function of two vectors corresponding to two current carrying line segments. Based on the obtained analytical expressions for the mutual inductance, the versatile calculation method for the self- and mutual inductances of various twisted conductors is studied by means of the broken line or polygonal curve approximation. In particular, it is confirmed that this numerical calculation is consistent with the analytical calculation of the self- and mutual inductances for coaxial helical conductors for the asymptotic form of the long axial length. Furthermore, for the inductances of general twisted conductors, the similar asymptotic forms of the length dependence are obtained.     

质谱法测量OLED封装材料的气体渗透率

本文介绍了质谱法渗透率测量系统和测量方法,利用该系统测量了水蒸汽、O2和CO2等气体对PET塑料薄膜和环氧树脂薄膜的渗透率,对所获得的实验结果进行了分析;结果表明PET塑料薄膜的水蒸汽渗透系数为1.76×10-6cm2/s,O2和CO2的渗透系数分别为4.5×10-9,2.25×10-8cm2/s,DG-4型环氧树脂的水蒸汽、O2和CO2的渗透系数分别为1.4×10-6,4.85×10-11和8.5×10-10cm2/s。实验结果表明PET塑料和环氧树脂的水和氧的渗透率很大,不适合作为长寿命OLED的封装材料;本文还讨论了所使用的质谱法渗透率测量系统存在的问题,以及该系统的改进方法。     

A Method for Evaluating the Thickness of Ultrathin Coatings from X-ray Photoelectron Spectroscopy Data

A method is proposed for evaluating the thickness of ultrathin films from x-ray photoelectron spectroscopy data with allowance made for photoelectron elastic scattering in solids and nondipolar transitions in photoionization. Two procedures for varying the photoelectron path in a film are examined: by rotating the analyzer and the sample. Both approaches have significant advantages over the straight-line approximation, which does not take into account elastic scattering. Experimental data are simulated using the Monte Carlo method. The two procedures ensure roughly equal accuracies (about 6%) in reproducing the thicknesses of surface films used in simulations.     

用Langmuir探针法标定的发射光谱法诊断等离子体电子密度及分布

电子密度是低温等离子体的重要参数之一,仅采用发射光谱或Langmuir探针一种诊断方法,很难测量出该参数及其分布。针对这一问题,提出了用Langmuir探针法标定的发射光谱法,用于诊断等离子体电子密度及其分布。通过对一定长度表面波等离子体源的实验测量,验证了该方法的可行性。对于电子温度变化不大的等离子体,利用本文提出的诊断方法,可以测量出其电子密度及其分布。提出的诊断方法为低温等离子体参数的实验诊断提供了一种新的途径。     

Control of Carrier Distribution for Tailoring Superconducting Properties of Layered Cuprates

A general view has been developed to correlate spatial inhomogeneity in the carrier density over different dimensions in crystals of high-T _c cuprate superconductors to basic superconducting properties such as T _c , H _irr and peak effect. Employing the BVS concept, it is shown that there are three different routes for doping the CuO ₂ plane with holes, and that the more confined holes are in the middle of the CuO ₂ -plane stack, the higher is T _c . With the Cu(Ba,Sr) ₂ (Yb,Ca)Cu ₂ O _6+z system it is shown that the distribution of holes is different when holes are generated with different doping routes, and further that the more homogeneous the hole distribution along the c axis is, the better is the H _irr characteristics. This agrees with observations made for Hg-1223 and Cu-1223 that the more overdoped these phases are, the more improved is the H _irr characteristics. Studies on peak effect in various high-T _c superconductors indicate that some mesoscopical inhomogeneity in oxygen content or hole density causes the peak. Thus control of hole density over dimensions from atomic bonds to tens of nanometers is essential in tailoring the fundamental superconducting properties.     

圆弧形层状凹陷地形对平面SH波的散射

利用Fourier—Bessel级数展开法给出了圆弧形层状凹陷地形对平面SH波散射二维问题的一个解析解，分析了层状凹陷地形沉积排列顺序、软夹层刚度和厚度等因素对SH波散射的影响。结果表明，层状凹陷地形对平面SH波的散射和单一凹陷地形差别很大，凹陷地形表面松软沉积的存在，即使厚度很薄，也会大大降低凹陷地形本身对入射波的屏障作用；层状凹陷地形中沉积排列顺序、软夹层刚度和厚度的变化对散射也具有重要影响。     

核磁共振对一种聚酰胺酰亚胺构造的测定

以偏苯三酸酐和4,4,-二异氰酸酯二苯甲烷为主要原料,采用溶液缩聚法合成了一种聚酰胺酰亚胺树脂;通过衰减全反射傅里叶变换红外光谱和核磁共振波谱表征了该型树脂的构造,二维核磁共振的关联分析结果表明该型聚酰胺酰亚胺主链具有构造对称性,并且活性端基异氰酸酯被苯甲醇和苯酚封闭,合成的树脂为含有2种潜在活性氨基酯结构的聚合物。     

基于电场作用的混凝土渗透性评价方法研究进展与展望

渗透性是反映混凝土耐久性最为直接的指标,基于外加电场的作用可快速评价混凝土的渗透性。通过对比分析现有基于外加电场作用下的混凝土渗透性评价的测试手段,总结了不同方法的实验条件差异。认为应进一步研究外加电场的作用和混凝土的材料组成所引起的误差,加强评价方法的基础理论研究。提出了通过改变实验条件和引入混凝土电学性质变化率的定量评价方法的设想,以及重点开展在役混凝土结构评价方法研究的建议。     

利用稳态法测定不良导体的导热系数

测定不良导体的导热系数需要测出传热速率,利用稳态法可将传热速率的测量转换为测量散热铝盘的冷却速率,指出了稳态法测定导热系数的方案。利用Matlab分析温度随时间变化的函数,并用该函数对时间的一阶导数求出冷却速率。得到温度、时间、冷却速率各量之间的关系图象,给出样品材料导热系数的实验结果。