There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality.

Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

I and i

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

In this critical review, metal oxides-based materials for electrochemical supercapacitor (ES) electrodes are reviewed in detail together with a brief review of carbon materials and conducting polymers. Their advantages, disadvantages, and performance in ES electrodes are discussed through extensive analysis of the literature, and new trends in material development are also reviewed. Two important future research directions are indicated and summarized, based on results published in the literature: the development of composite and nanostructured ES materials to overcome the major challenge posed by the low energy density of ES (476 references).

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A review of electrode materials for electrochemical supercapacitors

1. Introduction 20642. Synthesis of Magnetic Nanoparticles 20662.1. Classical Synthesis by Coprecipitation 20662.2. Reactions in Constrained Environments 20682.3. Hydrothermal and High-TemperatureReactions20692.4. Sol-Gel Reactions 20702.5. Polyol Methods 20712.6. Flow Injection Syntheses 20712.7. Electrochemical Methods 20712.8. Aerosol/Vapor Methods 20712.9. Sonolysis 20723. Stabilization of Magnetic Particles 20723.1. Monomeric Stabilizers 20723.1.1. Carboxylates 20733.1.2. Phosphates 20733.2. Inorganic Materials 20733.2.1. Silica 20733.2.2. Gold 20743.3. Polymer Stabilizers 20743.3.1. Dextran 20743.3.2. Polyethylene Glycol (PEG) 20753.3.3. Polyvinyl Alcohol (PVA) 20753.3.4. Alginate 20753.3.5. Chitosan 20753.3.6. Other Polymers 20753.4. Other Strategies for Stabilization 20764. Methods of Vectorization of the Particles 20765. Structural and Physicochemical Characterization 20785.1. Size, Polydispersity, Shape, and SurfaceCharacterization20795.2. Structure of Ferro- or FerrimagneticNanoparticles20805.2.1. Ferro- and Ferrimagnetic Nanoparticles 20805.3. Use of Nanoparticles as Contrast Agents forMRI20825.3.1. High Anisotropy Model 20845.3.2. Small Crystal and Low Anisotropy EnergyLimit20855.3.3. Practical Interests of Magnetic NuclearRelaxation for the Characterization ofSuperparamagnetic Colloid20855.3.4. Relaxation of Agglomerated Systems 20856. Applications 20866.1. MRI: Cellular Labeling, Molecular Imaging(Inﬂammation, Apoptose, etc.)20866.2.

Magnetic Iron Oxide Nanoparticles: Synthesis, Stabilization, Vectorization, Physicochemical Characterizations, and Biological Applications

[Liu, Chang; Li, Feng; Ma, Lai-Peng; Cheng, Hui-Ming] Chinese Acad Sci, Inst Met Res, Shenyang Natl Lab Mat Sci, Shenyang 110016, Peoples R China.;Cheng, HM (reprint author), Chinese Acad Sci, Inst Met Res, Shenyang Natl Lab Mat Sci, 72 Wenhua Rd, Shenyang 110016, Peoples R China;cheng@imr.ac.cn

Advanced Materials for Energy Storage

The effect of an insulation lid on the growth of 4-inch β-Ga2O3 single crystals by the Czochralski method is analyzed by numerical simulation. The insulation lid mainly hinders upward radiant heat transfer from the melt and crucible and increases the axial temperature gradient in the crystal. Such benefits make the melt/crystal interface convex, which is conducive to suppressing spiral growth and growing large crystals with high quality. Materials with low thermal conductivity λ and low emissivity ε are the optimal choices for making an insulation lid. The inner hole has a great influence on the isolation of radiant heat, and it is determined that the maximum size of the inner diameter Din should not be larger than 130 mm. Thermal stress analysis results indicated that the insulation lid will cause a better stress distribution, illustrating the effect of the insulation lid on the quality of a cylindrical crystal.

/pdf/numerical-simulation-of-b-ga2o3-single-crystal-growth-by-3ii3mhb5.pdf

Numerical Simulation of β-Ga2O3 Single Crystal Growth by Czochralski Method with an Insulation Lid

The room-temperature electroluminescence (EL) band in the 1.2–1.7 μm range in boron-implanted silicon with implantation energy of 50 keV and 700 keV was investigated. This band is attributed to the defects in the implantation region introduced by implanted ions. The defects are unstable under the annealing temperature as low as 350°C. The EL intensity of the device implanted at 700 keV is much stronger than that of the device implanted at 50 keV due to the higher defect concentration and the improved minority carrier injection ratio. The absence of this band in photoluminescence measurements indicates that the luminescence band can only be electrically driven. Further enhancement of this EL band can be achieved by optimizing the implantation parameters.

Defect-Related Electroluminescence in the 1.2-1.7 μm Range from Boron-Implanted Silicon at Room Temperature

We prepared high-intensity luminescent films with a high LDP (Er3+ luminescence lifetime-concentration product) of 1.54 × 1019 s × cm-3, where lithium-doped erbium silicate grains are embedded in cristobalite. The near-infrared and up-conversion luminescence intensities of erbium silicate show ∼55 and 40 times enhancement by lithium-doping, respectively. Lithium-doping directly regulates the lattice structure of erbium silicate to enhance luminescence by reducing the crystal field symmetry around erbium, meanwhile, interstitial lithium does not dilute the concentration of erbium ions. Furthermore, lithium-containing dopants promote silica to crystallize, enhancing the luminescence of erbium silicate by reducing the interface defects. These films are expected to achieve high-gain film waveguide amplifiers in chip-scale optoelectronic integration. And this method opens up possibilities to be universally applicable to erbium compounds for enhancing luminescence by directly regulating the lattice structure.

Deren Yang

Papers

Numerical Simulation of β-Ga2O3 Single Crystal Growth by Czochralski Method with an Insulation Lid

Defect-Related Electroluminescence in the 1.2-1.7 μm Range from Boron-Implanted Silicon at Room Temperature

Enhanced luminescence of erbium silicate: interstitial lithium directly regulates the lattice structure of erbium compound crystals.