다중혈관 관상동맥 환자에서 y-문합을 이용하여 양쪽 내흉동맥만을 사용한 우회술의 조기 성적

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

The semiconductor ZnO has gained substantial interest in the research community in part because of its large exciton binding energy (60meV) which could lead to lasing action based on exciton recombination even above room temperature. Even though research focusing on ZnO goes back many decades, the renewed interest is fueled by availability of high-quality substrates and reports of p-type conduction and ferromagnetic behavior when doped with transitions metals, both of which remain controversial. It is this renewed interest in ZnO which forms the basis of this review. As mentioned already, ZnO is not new to the semiconductor field, with studies of its lattice parameter dating back to 1935 by Bunn [Proc. Phys. Soc. London 47, 836 (1935)], studies of its vibrational properties with Raman scattering in 1966 by Damen et al. [Phys. Rev. 142, 570 (1966)], detailed optical studies in 1954 by Mollwo [Z. Angew. Phys. 6, 257 (1954)], and its growth by chemical-vapor transport in 1970 by Galli and Coker [Appl. Phys. ...

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A comprehensive review of zno materials and devices

Dilute ferromagnetic oxides having Curie temperatures far in excess of 300 K and exceptionally large ordered moments per transition-metal cation challenge our understanding of magnetism in solids. These materials are high-k dielectrics with degenerate or thermally activated n-type semiconductivity. Conventional super-exchange or double-exchange interactions cannot produce long-range magnetic order at concentrations of magnetic cations of a few percent. We propose that ferromagnetic exchange here, and in dilute ferromagnetic nitrides, is mediated by shallow donor electrons that form bound magnetic polarons, which overlap to create a spin-split impurity band. The Curie temperature in the mean-field approximation varies as (xdelta)(1/2) where x and delta are the concentrations of magnetic cations and donors, respectively. High Curie temperatures arise only when empty minority-spin or majority-spin d states lie at the Fermi level in the impurity band. The magnetic phase diagram includes regions of semiconducting and metallic ferromagnetism, cluster paramagnetism, spin glass and canted antiferromagnetism.

Donor impurity band exchange in dilute ferromagnetic oxides.

Molecular self-assembly is the spontaneous association of molecules under equilibrium conditions into stable, structurally well-defined aggregates joined by noncovalent bonds. Molecular self-assembly is ubiquitous in biological systems and underlies the formation of a wide variety of complex biological structures. Understanding self-assembly and the associated noncovalent interactions that connect complementary interacting molecular surfaces in biological aggregates is a central concern in structural biochemistry. Self-assembly is also emerging as a new strategy in chemical synthesis, with the potential of generating nonbiological structures with dimensions of 1 to 10(2) nanometers (with molecular weights of 10(4) to 10(10) daltons). Structures in the upper part of this range of sizes are presently inaccessible through chemical synthesis, and the ability to prepare them would open a route to structures comparable in size (and perhaps complementary in function) to those that can be prepared by microlithography and other techniques of microfabrication.

Molecular self-assembly and nanochemistry: A chemical strategy for the synthesis of nanostructures

A review of recent advances in nonenzymatic glucose sensors.

An essential resource for scientists designing new energy materials for the vast landscape of solar energy conversion as well as materials processing and characterizatio.Based on the new and fundam ...

Advanced Energy Materials

Deacetylation of chitin affords chitosan, a polymer, widely studied for its pharmaceutical and nonpharmaceutical applications. The hurdle in comprehending these applications is its limited solubility. Carboxymethylation of chitosan helps to surmount this hurdle with its improved solubility in water. Though there is ample of research related to carboxymethyl chitosan (CMC) the focused review of the topic is unavailable. Hence an attempt is made in this review to cover the recent findings pertaining to synthesis, characterization of CMC and its applications especially in pharmaceutical field. CMC has been synthesized by ways as direct alkylation, reductive alkylation, Michael addition and characterized by FTIR, NMR spectroscopy, and DSC, titrimetry, viscometry, gel permeation chromatography, X-ray diffraction and capillary zone electrophoresis. The carboxymethyl group can be present at O or N or both the atoms of chitosan molecule. The CMC possess modulated physical and biological properties as chelating, sorption, moisture retention, cell functioning antioxidant, antibacterial, antiapoptotic etc. CMC is used in sustained or controlled release drug delivery, pH responsive drug delivery, DNA delivery as permeation enhancer etc. CMC can be further modified with alkylation, acylation, and grafting. Carboxyalkylation of chitosan yield carboxyethyl, carboxybutyl chitosans. These analogues of CMC may be helpful in substantiating the applications of chitosan. Copyright © 2010 VBRI press.

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Carboxymethyl chitosan and its applications

Here we report a systematic study of structural, optical, and magnetic measurements on epitaxial Zn0.9Co0.1O films grown on c-plane sapphire single crystal, at various temperatures (500–650°C), using pulsed-laser deposition. The main emphasis in this work has been on the correlation of microstructure with properties, specifically with magnetic properties and the fate of cobalt ions into substitutional sites versus precipitates. The reasons for room-temperature ferromagnetism are explored, and convincingly proved to be one of the inherent properties of the material. Most importantly, the presence of nanoclusters of any magnetic phase was ruled out. This was determined by high-resolution transmission electron microscopy, coupled with electron energy loss spectroscopy and STEM-Z (scanning transmission electron microscopy-atomic number) contrast studies.

Zn0.9Co0.1O-based diluted magnetic semiconducting thin films

In this paper, we report on the metal-semiconductor transition behavior observed in transparent and conducting ZnO:Ga films grown by pulsed-laser deposition. The electrical resistivity measurements were carried out on ZnO films with varying Ga concentration in the temperature range of 14to300K. The electrical properties were correlated with film structure, and detailed structural characterization was performed using x-ray diffraction, transmission electron microscopy, and x-ray photoelectron spectroscopy. The room-temperature resistivity of these films was found to decrease with Ga concentration up to 5% Ga, and then increase. The lowest value of resistivity (1.4×10−4Ωcm) was found at 5% Ga. Temperature dependent resistivity measurements showed a metal-semiconductor transition, which is rationalized by localization of degenerate electrons. A linear variation of conductivity with T below the transition temperature suggests that the degenerate electrons are in a weak-localization regime. It was also found t...

Ashutosh Tiwari

Papers

A review of recent advances in nonenzymatic glucose sensors.

Advanced Energy Materials

Carboxymethyl chitosan and its applications

Zn0.9Co0.1O-based diluted magnetic semiconducting thin films

Electrical properties of transparent and conducting Ga doped ZnO