软X光能谱仪求辐射能流的改进方法

使用多道软X光能谱仪测量黑腔辐射能流时间过程并使用最小二乘法将多道谱仪的响应函数线性组合为等效平响应。针对惯性约束聚变实验中软X光能谱强度分布不均匀、等效平响应局部不平带来的误差,提出了辐射能流求解的加权改进算法。对不同谱形和等效积分温度的能谱进行了计算,比较了不同方法得到的能流还原能力。改进后的方法应用于实验数据的处理,得到了修正后的等效积分温度随时间的演化过程。     

聚合物泡沫结构及密度分布的相衬CT表征技术

阐述了利用X射线相衬成像技术研究高分子有机泡沫材料微观结构的原理及方法,理论分析及实验结果表明,X射线相衬成像方法可以在相当大的程度上提高低Z聚合物泡沫材料的成像衬度。将相衬成像技术与计算机层析成像技术相结合,获得了泡沫样品的3维骨架结构分布,同时,提出利用统计切片骨架"粒子"质心分布的方法来表征其密度分布均匀性。结果说明,该方法能够在微观层次上实现对泡沫样品3维密度分布的完备表征。     

Chiral symmetry restoration in excited hadrons and dense matter

We overview two interconnected topics: possible effective restoration of chiral symmetry in highly excited hadrons and possible existence of confined but chirally symmetric matter at low temperatures and high densities.     

Chiral symmetry restoration in excited hadrons and dense matter

We overview two interconnected topics： possible effective restoration of chiral symmetry in highly excited hadrons and possible existence of confined but chirally symmetric matter at low temperatures and high densities.     

Sputtered amorphous Co-Pt-P thin films for soft underlayer of perpendicular magnetic recording

In this paper, a novel amorphous Co-Pt-P thin film fabricated by DC sputtering was proposed for soft underlayer in perpendicular recording. The structural and magnetic properties of the films were investigated by X-ray diffraction (XRD) and vibrating sample magnetometer (VSM), respectively. The results show that maximum permeability of Co-12 at%Pt-P films sputtered at room temperature (RT) is quite low when the phosphorus content is less than 5.2 at%, but Co-12 at%Pt-7 at%P thin film, is of amorphous state and has a high permeability of ∼500. The excellent soft magnetic properties of maximum permeability (500), coercivity (18 Oe) and saturation magnetization (760 emu/cm³) indicate that the amorphous Co-12 at%Pt-7 at%P film is expected to be a promising soft magnetic underlayer of perpendicular magnetic recording. The Co-12 at%Pt-7 at%P thin film is gradually crystallized with increasing substrate temperatures. The crystallization temperature of the Co-12 at%Pt-7 at%P thin film is ∼200 °C.     

Magnetic measurements of Fe-Ni-Nb-B and Fe-Co-Mo-Cu-B in the vicinity of the Curie temperature

The study of the transition between ferromagnetic and paramagnetic states has been investigated on selected metallic glass systems based on Fe-Ni-Nb-B and Fe-Co-Mo-Cu-B with T_C close to room temperature. Samples in the form of ribbons were prepared by planar flow casting and magnetostriction in parallel and perpendicular directions and saturation magnetostrictions have been determined on these samples in as-cast states together with hysteresis loops. In addition, a magneto-optic device for dynamic domain observation has been used for observation of domain structure. Magnetostriction measurements using direct method of measurement show the decrease of saturation magnetostriction towards zero upon approaching T_C. In paramagnetic state the field dependencies of magnetostriction in parallel and perpendicular configurations exhibit a linear dependence on the external magnetic field. In the transition region of temperatures the dependencies are a combination of ferromagnetic and paramagnetic field dependencies. The coercivity H_C in the materials investigated exhibits values below 20 A/m. The observed magnetic domains are typical for this class of amorphous alloys. The polarization in paramagnetic state increases gradually with increase in magnetizing field, reflecting the increasing amount of polarized regions.     

NiZnCu ferrite applied for LTCC microinductor

This paper describes the fabrication of thin magnetic layers for an LTCC planar-type inductor with a 0.11 mm thickness. The thin ferrite layers were fabricated by tape casting method. Synthesis conditions and X-ray analysis (300 K) of the Ni_0.3Zn_0.62Cu_0.08Fe₂O₄ ferrite are presented. A pure cubic, Fd 3m crystal structure was observed for the Ni_0.3Zn_0.62Cu_0.08Fe₂O₄ ferrite. The complex impedance and dielectric permittivity of Ni_0.3Zn_0.62Cu_0.08Fe₂O₄ ferrite were determined as a function of temperature (from −55 to 170 °C) and frequency (from 10 Hz to 2 MHz). Dc resistivity was measured in a temperature range from −55 to 170 °C. Magnetization and magnetic hysteresis were measured by a vibrating sample magnetometer (VSM) in an applied magnetic field up to 60 kOe. The inductance and quality factor were measured in a frequency range 0.1-120 MHz. With the help of finite elements method (FEM) simulation it is possible to calculate the elements electrical parameters and optimize the design. This paper presents a magnetic field modelling of an inductor structure.     

The exact decomposition of gauge variables in lattice Yang–Mills theory

In this Letter, we consider lattice versions of the decomposition of the Yang–Mills field a la Cho–Faddeev–Niemi, which was extended by Kondo, Shinohara and Murakami in the continuum formulation. For the SU(N)$\mathit{SU}(N)$ gauge group, we propose a set of defining equations for specifying the decomposition of the gauge link variable and solve them exactly without using the ansatz adopted in the previous studies for SU(2)$\mathit{SU}(2)$ and SU(3)$\mathit{SU}(3)$. As a result, we obtain the general form of the decomposition for SU(N)$\mathit{SU}(N)$ gauge link variables and confirm the previous results obtained for SU(2)$\mathit{SU}(2)$ and SU(3)$\mathit{SU}(3)$.     

Relationship between crystal morphology and photoluminescence in polynanocrystalline lead sulfide thin films

Thin films of lead sulfide (PbS) nanoparticles were grown on corning glass and Si(1 0 0) substrates by polyethylene glycol-assisted chemical bath deposition (CBD) method. This paper compares the morphology and the luminescence properties (PL) of the deposited thin films in the presence (or absence) of PEG300 and investigates the effect of deposition temperatures. Surface morphology and photoluminescence properties of samples were analyzed. The PL data show a blue-shift from the normal emission at ∼2900 nm in PbS bulk to ∼360 nm in nanoparticles of PbS thin films. Furthermore, the PL emission of the films obtained without the addition of PEG300 (type 1) was slightly shifted from that of the films obtained in presence of PEG300 (type 2) from ∼360 to ∼470 nm. The blue-shifting of the emission wavelengths from 2900 to ∼360 or 470 nm is attributed to quantum confinement of charge carriers in the restricted volume of nanoparticles, while the shift between the two types of PbS nanoparticles thin films is speculated to be due to an increase in the defect concentration. The blue-shift increased with increase of the deposition temperature, which suggests that there has been a relative depletion in particle sizes during the CBD of the films at higher temperatures. The PbS nanocrystalline thin films obtained in the presence of PEG300 at 60 °C exhibit a high blue luminescence.     

Influence of polyethylene glycol-300 addition on nanostructured lead sulfide thin films properties

The concentration of polyethylene glycol-300 was found to play a crucial role in the formation of nanoparticles in PbS-chemical bath deposition process. We report here an endeavor to set up a relation between the variation of lead sulfide (PbS) nanocrystalline thin film properties, grown by (CBD) process at room temperature on corning glass and Si(100) substrates, with amount fluctuations of polyethylene glycol-300 in the solution. The transmittance of the films, for a fixed reaction time, increased up to ∼ 80% with the increase of % polyethylene glycol-300 in the solution, indicating the formation of very thin films due to the decrease of reaction rate with the increase of the concentration of polyethylene glycol-300. The optical band gaps were found to strongly rely on the composition of the bath deposition and increase with the increase of the polyethylene glycol-300 amount in the solution. Particle sizes between 2.8 and 8.7 nm were obtained by varying the % of polyethylene glycol-300 from 0.2 to 1.5. The concentration of polyethylene glycol-300 not only affects the reaction rate but also the morphology of the obtained films. PbS nanoparticles were found to be oriented preferentially along the < 200> plane. The absorption shifts towards short wavelength indicating a blue-shifting as a consequence of quantum confinement.