A novel zinc tartrate oriented hydrothermal synthesis of microporous carbons was reported. Zinc organic complex obtained via a simple chelation reaction of zinc ions and tartaric acid is introduced into the networks of resorcinol/formaldehyde polymer under hydrothermal condition. After carbonization process, the resultant microporous carbons achieve high surface area (up to 1255 m(2)/g) and large mean pore size (1.99 nm) which guarantee both high specific capacitance (225 F/g at 1.0 A/g) and fast charge/discharge operation (20 A/g) when used as a supercapacitor electrode. Besides, the carbon electrode shows good cycling stability, with similar to 93% capacitance retention at 1.0 A/g after 1000 cycles. The well designed and high-performance microporous carbons provide important prospects for supercapacitor applications. (C) 2016 Chinese Chemical Society and Institute of Materia Medica, Chinese Academy of Medical Sciences. Published by Elsevier B.V. All rights reserved.

The reflective phase shift of multilayer mirror is one important property required in EUV lithography and attosecond pulses experiments. The reflective phase shift of the periodic Mo/Si multilayer mirror was characterized by combining the reflectivity with total electron yield signal at the synchrotron radiation in Hefei. The multilayer was fabricated using direct current magnetic sputtering method. Using the wavelet transform approach, the period and each layer thickness were obtained, the small angle X-ray reflective data from X-ray diffractometer were fitted using these data as the mutilayer's initial structure. The TEY signal of the multilayer is coincided with the surface electron field of the multilayer. A thick Si layer was used to eliminate the effect of the multilayer's surface layer on the TEY signal. The retrieved difference in reflected phase from the incident phase was obtained combining the reflectivity with the total electron yield signal and it is similar with the calculated phase shift of the multilayer.

Mo/Si multilayer are normally used in the early extreme ultraviolet (EUV) astronomical observation. In recent years people want to get observations in higher spectral resolution. Multilayer with low=Z materials have been studied. Four kinds of multilayer, Mg/SiC, Si/SiC, Si/B4C and Si/C multilayer were designed at the wavelength of 30.4 nm and compared with the normal Mo/Si multilayer. All the multilayer were prepared with DC magnetron sputtering, and their reflectivities were measured by synchrotron radiation. The results show that the bandwidth of Mg/SiC multilayer is 1.44 nm, which is the smallest, and the reflectivity is 44%, which is the highest. While the reflectivity of Mo/Si multilayer is only 24% and the bandwidth is 3.11 nm. The bandwidths of multilayer of low=Z materials are narrower than that of the normal multilayer. Therefore, multilayer of low=Z materials can be used in the EUV high spectral resolution field.

To develop high quality dispersion optics in the X-ray region, the sliced multilayer transmission grating is examined. Dynamical diffraction theory is used to calculate the diffraction property of this volume grating. A WSi2/Si multilayer with a d-spacing of 14.3 nm and bi-layer number of 300 is deposited on a superpolished silicon substrate by direct current magnetron sputtering technology. To make the transmission grating, the multilayer is sliced and thinned in the cross-section direction to a depth of 23-25 μm. The diffraction efficiency of the grating is measured at E = 8.05 keV, and the 1st-order efficiency is 19%. The sliced multilayer grating with large aspect ratio and nanometer period can be used for high efficiency and high dispersion optics in the X-ray region.

For extreme ultraviolet (EUV) radiation and soft X-rays, real part of the refractive indices of all materials are very close to unity, coupled with high absorption, makes the realization of high-reflective mirrors (just like visible and infrared light) impossible. Multilayer is a nano-structure, alternating of low-and high-Z materials in a periodic way, which can greatly enhance the reflectivity via the interference of light reflected from interfaces, like crystal optics. Reflective mirrors, polarization elements, monochromators, etc, can be made basing on multi-layer structures. Zone plate is a powerful tool to focus the light beam for EUV and soft X-ray into nanometer scale, which is produced by electron beam etching method. However, for hard X-ray, the zone plate will has smaller width of outmost layer and larger aspect ratio, which is difficult to realize. Multilayer Laue lens (MLL) is a promising method to overcome these limitations. MLL is a novel linear zone plate which is produced by depositing the depth-graded multilayer, according to the zone plate law reversely, on flat substrate and then slicing and polishing it to an ideal aspect ratio. In this paper, some recent development of multilayer optics for EUV and X-ray regions in IPOE will be introduced.

Mutilayers are important optical elements and widely used for extreme ultraviolet astronomical observation. For selecting the emission line multilayers should have high reflectivity and narrow spectral bandwidth. In this paper, six different multilayers including Si/C, Si/B4C, Si/Mo/B4C, Si/SiC, Mg/SiC and Mo/Si were designed for normal incidence angle of 5 degrees at He-IIemission line(lambda=30.4 nm). These multilayers have been fabricated using a direct current magnetron sputtering system. The period of multilayers were measured by X-ray diffractometer(XRD) and the reflectivities were measured on National Synchrotron Radiation Facility in Hefei, China. Then the reflectivities and the spectral bandwidth of these multilayers were compared respectively. It shows that the spectral bandwidth of multilayers of low Z materials is narrower than that of the normal Mo/Si multiayer, the reflectivity of Si/Mo/B4C multilayer is higher than that of Si-based multilayers of two kinds of materials. And Mg/SiC multilayer has the highest reflectivity of 43.81% and the narrowest spectral bandwidth of 1.44nm, which proves that Mg/SiC multilayer is more potential for selecting the emission line in extreme ultraviolet solar physics.

In order to decrease the bandwidth of the normal multilayers and improve the spectral resolution,several kinds of multilayers composed of low-Z materials were investigated in extreme ultraviolet and soft X-ray regions.Firstly,three kinds of multilayers of low-Z materials,Si/B4C,Si/C and Si/SiC multilayers were chosen at the wavelength of 14 nm and these multilayers and a normal Mo/Si multilayer were designed by using a random search method.Then all these multilayers were fabricated with a DC magnetron sputtering system and the thicknesses were measured by an X-ray diffractometer.Finally,the reflectivities of multilayers were measured by the synchrotron radiation.The synchrotron radiation tests show that the largest bandwidth of these multilayers is from the Mo/Si multilayer in 0.57 nm,and the smallest one is from Si/SiC multilayer in 0.18 nm.The results correspond with the design and demonstrate that the bandwidths of multilayers of low-Z materials are narrower than that of the normal Mo/Si multilayer and the multilayers of low-Z materials can achieve a higher spectral resolution.

Design, fabrication and characterization of aperiodic tungsten/carbon (W/C) multi-layer mirror were studied. W/C multi-layer was designed as a broad-angle reflective supermirror for Cu–Kα line (λ=0.154nm) in the grazing incident angular range (0.9–1.1°) using simulated annealing algorithm. To deposit the W/C depth-graded multi-layer mirror accurately, we introduce an effective layer growth rate as a function of layer thickness. This method greatly improves the reflectivity curve compared to the conventional multi-layer mirror prepared with constant growth rate. The deposited multi-layer mirror exhibits an average reflectivity of 19% over the grazing incident angle range of 0.88–1.08° which mainly coincides with the designed value. Furthermore, the physical mechanisms were discussed and the re-sputtering process of light-atom layers is accounted for the modification of layer thicknesses which leads to the effective growth rates. Using this calibration method, the aperiodic multi-layer mirrors can be better fabricated for X-ray optics.

Aperiodic molybdenum/silicon (Mo/Si) multilayer designed as a broadband polarizer with reflectivity over a wide wavelength range of 13–30nm at a fixed incidence angle of 45° was developed by a numerical method. The multilayer was prepared using direct current magnetron sputtering. The reflectivity and polarizing properties were characterized using synchrotron radiation. In 13–30nm wavelength region, the measured s-reflectivity (Rs) with standard deviation is 13.5%±3.1%, p-reflectivity (Rp) with standard deviation is 1.4%±0.5%. The mean of polarization degree is 81.2%. This broadband multilayer polarizer can be used in extreme ultraviolet polarization measurements, and will greatly simplify experimental arrangements.

Mg/B4C multilayer provides very high theoretical reflectivity in extreme ultraviolet range near 30.4nm wavelength, while the interface between Mg and B4C layer is very poor. In this paper, Co was introduced into the interface between Mg and B4C as a barrier layer. Mg/B4C and Co/Mg/Co/B4C multilayers were designed, fabricated, and measured for the wavelength of 30.4nm. The thickness of Co barrier layer was optimized. Grazing incidence x-ray reflectance measurements show that the structural quality of Co/Mg/Co/B4C multilayer is improved significantly after Co barrier layer inserting, and the optimum thickness of the barrier layer is 1.5nm.

Theoretically, the spectral resolution of a multilayer can be improved through a combination of utilizing high reflectance orders and by decreasing the thickness of the scattering layer. We fabricate Mo/Si multilayers in the first, second, third, fourth and fifth reflectance orders with Mo layer thicknesses of 3.0 nm and 2.0 nm, respectively, using direct current magnetron sputtering. The structure of the multilayers is characterized with a grazing angle x-ray diffractometer (XRD). Then the reflectivity of the multilayers is measured in a synchrotron radiation facility. The results show that the spectral resolution increases with the increasing reflectance order and with the decreasing Mo layer thickness. The highest spectral resolution is improved to 117.5 in the 5th order for d(Mo) = 2 nm, where the reflectivity is 18%.

Chirped Mo/Si multilayer mirrors used in 13-17nm region have been designed using analytical approach based on the combination of genetic algorithm and simplex algorithm. The Cauchy equation and the polynomial expression were used to fit the real part and the imaginary part of the optical constants of Mo and Si in the wavelength region of 12.8-17.2nm, respectively. The reflectivity, reflective phase, group delay and group delay dispersion of the multilayer were calculated based on the Fresnel iterative equations. The initial structure of the multilayer was obtained by using the genetic algorithm, and the final structure of the mirror was optimized by using the simplex algorithm. We got the different multilayer mirrors for the target GDD of -2800 as(2), -3600 as(2), and -6500 as(2). For these three multilayer mirrors, the average reflectivities in the wavelength range of 13-17 nm are 7.00 +/- 0.08 %, 5.99 +/- 0.05 %, and 6.00 +/- 0.05 %, respectively. And the average GDD in the same wavelength range are -2793.22 +/- 104.00 as(2),-3597.44 +/- 79.06 as(2), and 6498.13 +/- 59.96 as(2). In addition, the effects of the interface roughness on the reflectivity and the phase were discussed. It is found that the reflectivity is sensitive to the interface roughness, but the phase is insensitive.

We investigate the adhesion mechanism of aluminum spheres on a silicon substrate. Aluminum particles in the size range of 60-1500 nm were deposited onto a silicon substrate. It was found that aluminum particles underwent plastic deformation rather than elastic deformation because of van der Waals interactions. A finite element model developed recently is also used to analyze our results. Because the MP model was proposed to describe plastic deformation based on an analysis of metal microcontacts, our results prove the correctness of the MP model from its origin and basis of arguments.

In this paper, Stöber process with high concentration of tetra-ethyl-orthosilicate (TEOS) up to 1.24 M is used to prepare monodisperse and uniform-size silica particles. The reactions are carried out at [TEOS]=0.22-1.24 M, low concentrations of ammonia ([NH(3)]=0.81[TEOS]), and [H(2)O]=6.25[TEOS] in isopropanol. The solids content in the resulting suspension achieves a maximum value of 7.45% at 1.24 M TEOS. Various-sized particles in the range of 30-1000 nm are synthesized. The influences of TEOS, NH(3), and H(2)O on the size and size distribution of the particles are discussed. A modified monomer addition model combined with aggregation model is proposed to analyze the formation mechanism of silica particles.

A multilayer Laue lens with a 15-nm outermost zone width is designed for an incident X-ray beam with an energy of 8 keV. WSi2/Si multilayer Laue lens with 324 layers and a total thickness of 7.9 \mu m is successfully fabricated using direct current magnetron sputtering method. After deposition, the multilayer is sliced and polished to achieve the ideal aspect ratio. Characterization results show that the multilayer structure is kept intact and the surface roughness is approximately 0.9 nm after slicing and repeated polishing.

To improve the stress property of multilayer optics working in extreme ultraviolet and x-ray range, mono-layer thin films of Mo, MoSi2, Si, with thickness of 100nm, and periodic multilayers of [Mo/Si]20, [MoSi2/Si]20, with period thickness of 20nm, were prepared by direct current magnetron sputtering method. Before and after each deposition, the radius of surface curvatures of substrates were measured using a stylus profiler and then the film stress was calculated. The measurement results indicate that, Mo, MoSi2 and Si mono-layer thin films all shows compressive stress, while Mo/Si multilayer shows tensile stress, i.e., the film stress changes significantly during Mo/Si multilayer growth. For MoSi2/Si multilayer, the film stress still keeps compressive, which indicates more stable stress property.

An important property of a supermirror is its critical angle,which is measured in multiples m of the critical angle of bulk nickel by convention.Adding Ni capping layer on the outmost of supermirrors,optimizing its key parameter ξ0 and introducing a novel parameter to design neutron supermirrors can offset the reflectivity limitation in m≤1 region.The designed Ni/Ti neutron supermirror has less bi-layer pairs(K=200) and large m value(m=3),which would be easier to fabricate.The effects of the surface and interfacial roughness on neutron supermirrors were discussed by using Nevot-Croce model to simulate the non-ideal interface of the supermirror.The calculation result shows that 1.5 nm interfacial roughness should be required to make m=3 neutron supermirror with 200 bi-layer pairs and more than 80% critical reflectivity.

Recent development of multilayer mirror and its applications in extreme ultraviolet (EUV), soft X-ray ranges in China was reviewed in this paper. Three types of multilayer mirrors were developed with special performance for dense plasma diagnostics, EUV astronomical observation. Firstly, dual-periodic W/B4C multilayer mirror was designed for Kirkpatrick–Baez (K–B) microscopy working at TiKα line (4.75keV), which is highly reflective both at hard X-ray (CuKα line at 8.05keV) and soft X-ray (4.75keV). Using this mirror, the K–B system can be aligned conveniently in air using hard X-ray instead of in vacuum. The second mirror is aperiodic Mg/SiC multilayer, also a bi-functional mirror with high reflectivity for He-II emission line (30.4nm) but suppressing He-I emission line (58.4nm) in astronomy observation, which will replace the traditional combination of periodic multilayer and the fragile film filter. This will be more safe in satellite launching. The third mirror is Mo/Si periodic multilayer, depositing on a parabolic substrate with diameter of 230mm, which is designed for EUV telescope for imaging of solar corona by selecting Fe-XII emission (19.5nm). The uniformity of lateral layer thickness distribution is within ±0.3% along the diameter of mirror, measured by X-ray reflectometry. The measured peak reflectivity is 42% at the wavelength of 19.5nm. All these multilayer mirrors were prepared by using magnetron sputtering system in our group.

A recent development of mirrors is reviewed in this letter. For some applications, such as the hard X-ray telescope, polarization measurements in synchrotron radiation facilities, extreme ultraviolet (EUV) solar observations, and dense plasma diagnostics in China, a series of non-periodic novel multilayers with special performance are developed. X-ray supermirror, EUV broadband polarizer, EUV wide-angular mirror, and double period Kirkpatrick-Baez (K-B) mirror are successfully designed by using different multilayer stack structures. OCIS codes: 310.0310, 340.0340, 350.1260. doi: 10.3788/COL201008S1.0163.