THE DESIGN AND ANALYSIS OF EXPERIMENTS. By Oscar Kempthorne. New York, John Wiley and Sons, Inc., 1952. 631 pp. $8.50. This book by a teacher of statistics (as well as a consultant for \"experimenters\") is a comprehensive study of the philosophical background for the statistical design of experiment. It is necessary to have some facility with algebraic notation and manipulation to be able to use the volume intelligently. The problems are presented from the theoretical point of view, without such practical examples as would be helpful for those not acquainted with mathematics. The mathematical justification for the techniques is given. As a somewhat advanced treatment of the design and analysis of experiments, this volume will be interesting and helpful for many who approach statistics theoretically as well as practically. With emphasis on the \"why,\" and with description given broadly, the author relates the subject matter to the general theory of statistics and to the general problem of experimental inference. MARGARET J. ROBERTSON

The Design and Analysis of Experiments

正しい方法がわかる臨床基本手技 : from the New England journal of medicine

New generation adsorbents for water treatment.

Large-scale electrolysis of water for hydrogen generation requires better catalysts to lower the kinetic barriers associated with the oxygen evolution reaction (OER). Although most OER catalysts are based on crystalline mixed-metal oxides, high activities can also be achieved with amorphous phases. Methods for producing amorphous materials, however, are not typically amenable to mixed-metal compositions. We demonstrate that a low-temperature process, photochemical metal-organic deposition, can produce amorphous (mixed) metal oxide films for OER catalysis. The films contain a homogeneous distribution of metals with compositions that can be accurately controlled. The catalytic properties of amorphous iron oxide prepared with this technique are superior to those of hematite, whereas the catalytic properties of a-Fe100-y-zCoyNizOx are comparable to those of noble metal oxide catalysts currently used in commercial electrolyzers.

https://science.sciencemag.org/content/sci/early/2013/03/27/science.1233638.full.pdf

Photochemical Route for Accessing Amorphous Metal Oxide Materials for Water Oxidation Catalysis

Control of spontaneously emitted light lies at the heart of quantum optics. It is essential for diverse applications ranging from miniature lasers and light-emitting diodes, to single-photon sources for quantum information, and to solar energy harvesting. To explore such new quantum optics applications, a suitably tailored dielectric environment is required in which the vacuum fluctuations that control spontaneous emission can be manipulated. Photonic crystals provide such an environment: they strongly modify the vacuum fluctuations, causing the decay of emitted light to be accelerated or slowed down, to reveal unusual statistics, or to be completely inhibited in the ideal case of a photonic bandgap. Here we study spontaneous emission from semiconductor quantum dots embedded in inverse opal photonic crystals. We show that the spectral distribution and time-dependent decay of light emitted from excitons confined in the quantum dots are controlled by the host photonic crystal. Modified emission is observed over large frequency bandwidths of 10%, orders of magnitude larger than reported for resonant optical microcavities. Both inhibited and enhanced decay rates are observed depending on the optical emission frequency, and they are controlled by the crystals’ lattice parameter. Our experimental results provide a basis for all-solid-state dynamic control
of optical quantum systems.

Controlling the dynamics of spontaneous emission from quantum dots by photonic crystals

2D-perovskites are generally more stable than 3D perovskites while charge transport in 2D-perovskites becomes inefficient. On the other hand, the instability of 3D perovskite films under heat, light and environmental conditions makes them inapplicable for practical purposes. Therefore, quasi-2D perovskites could be the optimum solution for stable yet highly efficient devices. Using the post-fabrication treatment method, we have converted methylammonium lead tribromide (MAPbBr3) 3D perovskite films into a quasi 2D-perovskite interfacial layer. In situ photoluminescence measurement during spin coating indicates a rapid conversion of 3D-perovskite into 2D-perovskites. The kinetics of oxygen and moisture diffusion, ion diffusion and electronic charge transport can be estimated from the time dependent PL measurements in the 3D and 2D/3D perovskite samples. 2D terminated perovskite samples show enhanced photoluminescence and improved stability in moisture and UV-irradiation. We also propose that a relatively wide bandgap of 2D-perovskite can give rise to a graded energy landscape at the interface for favorable charge separation. Simulation results reveal that the power conversion efficiency can be improved from 2.83% to 4.02% due to an increase in open-circuit voltage and fill factor in 2D/3D based MAPbBr3 solar cells without using any electron transport layer.

Visualization of 3D to quasi 2D conversion of perovskite thin films via in situ photoluminescence measurement: a facile route to design a graded energy landscape.

We have theoretically investigated the effect of shape anisotropy and size on electronic structure of GaAs/AlGaAs quantum dots (QDs). The quantum dot is modeled by anisotropic parabolic confinement potential in the plane perpendicular to the growth direction while the confinement along the growth direction is modeled as quantum well potential. The Luttinger Hamiltonian formulation has been used to account for the valence subband mixing. The electronic structure is calculated by numerical diagonalization of Luttinger Hamiltonian using the harmonic oscillator basis functions. The calculations for hole energies and transition energies have been carried out over wide range of size and shape of QDs. The results show that transition energy of QDs decreases with the height of QDs. Significant variation in the hole energy is observed with the change in anisotropy. We also observe that shape anisotropy and mixing have significant effect on the energy states.

/pdf/shape-and-size-dependent-electronic-properties-of-gaas-37hofs7rvq.pdf

Shape and Size Dependent Electronic Properties of GaAs/AlGaAs Quantum Dots

A theoretical analysis of the optical characteristics and polarization properties of quantum dot laser which uses interband transitions in shape asymmetric InGaAs/GaAs QDs is presented. We use multi-band effective mass k.p model with the strain effect taken into account to compute the electronic structure of asymmetric QDs. In-plane shape asymmetry in QDs is accounted through the anisotropic parabolic potential. The optical gain spectrum is calculated using the density matrix approach. We have solved coupled set of rate equations numerically using fourth-order Runge Kutta method to analyze the dynamic characteristics of InGaAs/GaAs quantum dot laser. The effect of shape anisotropy, material composition, carrier densities and strain on light emission polarization ratio has been studied. The dependence of gain on polarization direction has been explained in terms of the valence band mixing. The polarization is found to increase almost linearly with anisotropy parameter and decreases with the material composition. Furthermore, it is demonstrated that anisotropy and strain can be used to control the polarization. We found that the output has preferential polarization properties depending on the QD structure and composition.

Analysis of polarized light generation in anisotropic strained quantum dots

ZN-PT single crystals of composition (91/9 and 92/8) were grown by flux technique. The effect of PT content on the disordering nature of the crystals was analyzed by Raman spectroscopy. The mechanical properties were analyzed from Vickers microhardness measurements to see the stress induced due to variation of PT composition. From the piezoelectric properties of (001) oriented crystals, the significance of MPB due to PT concentration in PZN-PT is clearly understood.

Influence of PT composition on the properties of PZN-PT single crystals

(111)- and (001)-oriented InP bulk single crystals double-doped with Cd and S were investigated by scanning electron microscopy in the cathodoluminescence mode, X-ray topography and transmission electron microscopy. Both cathodoluminescence micrographs and X-ray topographs showed that the crystals contain a low concentration of dislocations; however, in the less dislocated regions precipitate-like defects have been revealed. Transmission electron micrographs confirmed this result, showing the presence of defects exhibiting moire fringes; analysis of the fringe spacing and diffraction patterns evidenced the presence of crystalline CdS particles as responsible for the precipitate-like contrast.

Jitendra Kumar

Papers

Visualization of 3D to quasi 2D conversion of perovskite thin films via in situ photoluminescence measurement: a facile route to design a graded energy landscape.

Shape and Size Dependent Electronic Properties of GaAs/AlGaAs Quantum Dots

Analysis of polarized light generation in anisotropic strained quantum dots

Influence of PT composition on the properties of PZN-PT single crystals

Inclusions in co-doped InP single crystals