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

Effect of nitrogen–oxygen (N–O) complexes on electrical properties of nitrogen‐rich Czochralski (CZ) silicon grown in a nitrogen atmosphere has been investigated during annealing in the temperature range from 650 to 1000 °C. Electrical and low temperature (8 K) Fourier transmission infrared spectrometer (FTIR) measurements point out that the carrier concentration of the nitrogen‐rich silicon varies with the annealing time and temperature, which is due to the formation and elimination of the N–O complexes acting as shallow thermal donors. After the N–O complexes are eliminated by annealing above 900 °C the carrier concentration of the nitrogen‐rich silicon is stabilized. It is suggested that the N–O complexes attract more oxygen atoms to form new electrically inactive N–O clusters, and lose their electrical activity.

Effect of nitrogen–oxygen complex on electrical properties of Czochralski silicon

A novel layer-by-layer approach has been developed to synthesize polycrystalline SnO2 hollow spheres with tunable shell thickness and size using SiO2 spheres as a template. The surface of the SiO2 spheres has been first modified by the polyelectrolyte, and subsequently, the compact SnO2 layer has deposited on the surface of the SiO2 spheres through a redox reaction because of the electrostatic attraction between the charged species. After HF etching treatment, the uniform SnO2 hollow spheres have been obtained. The approach presented herein has been extended to synthesize other metal oxide and sulfide hollow spheres such as In2O3 and ZnS. Moreover, the as-synthesized SnO2 hollow spheres have been applied in lithium-ion battery and show improved performance compared with SnO2 nanoparticles. The high surface area and stable hollow structure of the SnO2 hollow spheres may be responsible for the improved performance.

Metal oxide and sulfide hollow spheres: layer-by-layer synthesis and their application in lithium-ion battery.

Using a simple chemical reaction, a new nanostructure of silver, which we call a "flower-like silver structure", is produced. The flower-like silver structure consists of a silver core and many rod-like tips protruding out in three dimensions. Besides common face-centered-cubic (FCC) phase of silver, there exists hexagonal-close-packed (HCP) phase in these tips. The appearance of HCP silver is the result of rapid growth of silver nuclei when using CH(2)O or C(2)H(4)O as the reducing agent. The formation of the rod-like tips is caused by the anisotropic growth determined by the HCP phase and the directing role of formic acid, which is the oxidation product of CH(2)O. It is also found that the concentration of reactants, the kind of reducing agents and the sequence of adding reactants can influence the morphology and phase constitution of the final products.

Fabrication of Flower-Like Silver Structures through Anisotropic Growth

Hexagonal Pd nanosheets with extremely thin thickness are synthesized in high yields by reducing the Pd salt precursor in N,N-dimethylformamide (DMF) containing tungsten hexacarbonyl (W(CO)6), citric acid (CA), and cetyltrimethylammonium bromide (CTAB). During the reaction, W(CO)6 spontaneously decomposes to W particles and CO, serving as reducing and capping agents in the synthesis of Pd nanosheets, respectively. We found that the use of CA and CTAB is both beneficial to promote the formation of hexagonal Pd nanosheets with stacking faults. In addition, the edge length of the Pd nanosheets can be simply tuned by varying the amount of CA fed in the synthesis. Such nanosheets can be further grown by subsequent seeded growth with as-preformed Pd nanosheets as the seeds. The Pd nanosheets with different edge lengths exhibit tunable localized surface plasmon resonance (LSPR) in the range of 820–1067 nm, and thus hold great potential in the field of plasmon-enhanced catalysis.

Deren Yang

Papers

Effect of nitrogen–oxygen complex on electrical properties of Czochralski silicon

Metal oxide and sulfide hollow spheres: layer-by-layer synthesis and their application in lithium-ion battery.

Fabrication of Flower-Like Silver Structures through Anisotropic Growth

Size-controlled synthesis of Pd nanosheets for tunable plasmonic properties

Order-aligned Mn3O4 nanostructures as super high-rate electrodes for rechargeable lithium-ion batteries