Cochran's statistical theorem for outer inverses of matrices and matrix quadratic forms

We extend the matrix version of Cochran's statistical theorem to outer inverses of a matrix. As applications, we investigate the Wishartness and independence of matrix quadratic forms for Kronecker product covariance structures.     

Nanotechnology in the Chemical Industry – Opportunities and Challenges

The traditional chemical industry has become a largely mature industry with many commodity products based on established technologies. Therefore, new product and market opportunities will more likely come from speciality chemicals, and from new functionalities obtained from new processing technologies as well as new microstructure control methodologies. It is a well-known fact that in addition to its molecular structure, the microstructure of a material is key to determining its properties. Controlling structures at the micro- and nano-levels is therefore essential to new discoveries. For this article, we define nanotechnology as the controlled manipulation of nanomaterials with at least one dimension less than 100nm. Nanotechnology is emerging as one of the principal areas of investigation that is integrating chemistry and materials science, and in some cases integrating these with biology to create new and yet undiscovered properties that can be exploited to gain new market opportunities. In this article market opportunities for nanotechnology will be presented from an industrial perspective covering electronic, biomedical, performance materials, and consumer products. Manufacturing technology challenges will be identified, including operations ranging from particle formation, coating, dispersion, to characterization, modeling, and simulation. Finally, a nanotechnology innovation roadmap is proposed wherein the interplay between the development of nanoscale building blocks, product design, process design, and value chain integration is identified. A suggestion is made for an R&D model combining market pull and technology push as a way to quickly exploit the advantages in nanotechnology and translate these into customer benefits.     

Low Cost, High Efficiency, Gain Flattened L Band EDFA Using FBGs as C Band Seed Generators

A low cost, coolerless 980nm diode pumped, gain flattened L band EDFA with fast transient control, high pump efficiency and gain clamping effect was realized by using FBGs as C band seed generators.     

Influence of solvents on the formation of ultrathin uniform poly(vinyl pyrrolidone) nanofibers with electrospinning

Although there have been many reports on the preparation and applications of various polymer nanofibers with the electrospinning technique, the understanding of synthetic parameters in electrospinning remains limited. In this article, we investigate experimentally the influence of solvents on the morphology of the poly(vinyl pyrrolidone) (PVP) micro/nanofibers prepared by electrospinning PVP solution in different solvents, including ethanol, dichloromethane (MC) and N,N‐dimethylformamide (DMF). Using 4 wt % PVP solutions, the PVP fibers prepared from MC and DMF solvents had a shape like a bead‐on‐a‐string. In contrast, smooth PVP nanofibers were obtained with ethanol as a solvent although the size distribution of the fibers was somewhat broadened. In an effort to prepare PVP nanofibers with small diameters and narrow size distributions, we developed a strategy of using mixed solvents. The experimental results showed that when the ratio of DMF to ethanol was 50:50 (w/w), regular cylindrical PVP nanofibers with a diameter of 20 nm were successfully prepared. The formation of these thinnest nanofibers could be attributed to the combined effects of ethanol and DMF solvents that optimize the solution viscosity and charge density of the polymer jet. In addition, an interesting helical‐shaped fiber was obtained from 20 wt % PVP solution in a 50:50 (w/w) mixed ethanol/DMF solvent. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 3721–3726, 2004     

Estimation of kinetics parameters for the adsorption of human serum albumin onto hydroxyapatite-modified silver electrodes by piezoelectric quartz crystal impedance analysis.

The adsorption of human serum albumin onto hydroxyapatite-modified silver electrodes has been in situ investigated by utilizing the piezoelectric quartz crystal impedance technique. The changes of equivalent circuit parameters were used to interpret the adsorption process. A kinetic model of two consecutive steps was derived to describe the process and compared with a first-order kinetic model by using residual analysis. The experimental data of frequency shift fitted to the model and kinetics parameters, k1, k2, psi1, psi2 and qr, were obtained. All fitted results were in reasonable agreement with the corresponding experimental results. Two adsorption constants (7.19 kJ mol(-1) and 22.89 kJ mol(-1)) were calculated according to the Arrhenius formula.     

Kähler-Einstein metrics with positive scalar curvature

In this paper, we prove that the existence of K?hler-Einstein metrics implies the stability of the underlying K?hler manifold in a suitable sense. In particular, this disproves a long-standing conjecture that a compact K?hler manifold admits K?hler-Einstein metrics if it has positive first Chern class and no nontrivial holomorphic vector fields. We will also establish an analytic criterion for the existence of K?hler-Einstein metrics. Our arguments also yield that the analytic criterion is satisfied on stable K?hler manifolds, provided that the partial C ⁰-estimate posed in [T6] is true. Oblatum 12-IV-1996 & 8-XI-1996     

激光调Q CAI

从激光调Q速率方程出发,分析推导了激光调Q过程中,腔内光子数与工作物质内反转粒子数间的关系.再根据激光调Q的过程中,对腔Q值控制方式不同,将激光调Q技术分为:转镜调Q、声光调Q、电光调Q、饱和吸收调Q和脉冲透射式调Q.用C语言进行了激光调Q CAI软件的开发研制,获得了将文学、图形、动画和计算融为一体的,直观而生动地将调Q的理论和过程再现于屏幕的CAI课件.介绍了课件的内容、结构及其特点.     

Preparation and structural stability investigation of CoN/CN soft X-ray multilayers

The structural stability of heat-treated CoN/CN soft X-ray multilayers fabricated by dual-facing-target sputtering has been investigated by using complementary measurement techniques. The high temperature annealing results imply that the destructive threshold of the Co/C multilayers is improved by 100–200 degrees centigrade through doping with N. The low-angle X-ray diffraction of CoN/CN soft X-ray multilayers indicates that the period expansion of the multilayers is only 4 % at 400°C, and the interface pattern still exists even if they were annealed at 700°C. The Raman spectra analyses give the evidence that the formation of the sp³ bonding in the CN sublayers can be suppressed effectively by doping N with atoms, and thus the period expansion resulting from the changes in the density of CN layers can be decreased considerably. The X-ray photoelectron spectra analyses present the information of the existence of the strong covalent bonding betweenC andN atoms, and the ionic bonding between Co and N atoms, which can slow down the tendency of the structural relaxation. The interstitial N atoms decrease the mobility of Co atoms, and thus the fcc-Co and hcp-Co coexist even though the annealing temperature is much higher than the phase transformation temperature of 420°C, leading to the suppression of the grain growth.