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

Role of metal impurities in multicrystalline silicon solar cell degradation

The thermal donor formation at 425oC - 450oC in Ge doped Czochralski (GCZ) silicon having about 1016 cm-3 Ge content pretreated by rapid thermal annealing (RTA) and conventional furnace annealing (CFA) has been investigated using low-temperature infrared spectroscopy (LT-IR). The measurements prove that lightly Ge doping can enhance the formation of thermal double donors in the initial stage of the low temperature annealing after RTA process. Ge induced additional grown-in oxygen precipitates during silicon ingot growth and the abundant self-interstitials during RTA may be the reason for the enhancement. However, after extending the annealing time at the low temperatures, the thermal donor concentration in the GCZ silicon is lower than that in the conventional CZ silicon. In final, the mechanism is also discussed.

Enhanced Formation of Thermal Donors in Germanium Doped Czochralski Silicon Pretreated by Rapid Thermal Annealing

A New Design of Side Heater for 3D Solid-liquid Interface Improvement in G8 Directional Solidification Silicon Ingot Growth

The influence of external high pressure (1 GPa) on oxygen precipitation in Czochralski (Cz) silicon annealed at 450°C has been investigated by means of transmission electron microscopy. It is found that low-temperature annealing under high-pressure results in the tiny sphere-like oxygen precipitates, which can be ascribed to the factors of lower self-interstitial concentration, higher vacancy concentration, and lower diffusivity of interstitial oxygen in silicon crystal exerted by the high pressure. The formation of sphere-like precipitate, which is favorable for minimizing the contribution of interfacial energy to the total precipitate free energy, is probably due to the fact that the annealing for 10 h is still in the early stage of oxygen precipitation.

Oxygen precipitation in Czochralski silicon annealed at 450°C under a high pressure of 1 GPa

Grown-in defects in an apparently dislocation-free heavily phosphorus (P)-doped Czochralski silicon (CZ-Si) crystal ingot were investigated by preferential etching and transmission electron microscopy (TEM). It was found that large-sized grown-in oxygen precipitates and the extended defects were present in the tang-end of the ingot. It is believed that oxygen precipitation in the tang-end ingot is enhanced by carbon (C) and by vacancies. Moreover, it was considered that phosphorus atoms might preferentially segregate on oxygen precipitates and caused high strain in silicon crystal. It is suggested that the large-sized precipitate might punch out dislocation loops under exceed stress during crystal growth. Finally, a tentative explanation for generation of grown-in defects in heavily P-doped CZ-Si is presented.

Deren Yang

Papers

Role of metal impurities in multicrystalline silicon solar cell degradation

Enhanced Formation of Thermal Donors in Germanium Doped Czochralski Silicon Pretreated by Rapid Thermal Annealing

A New Design of Side Heater for 3D Solid-liquid Interface Improvement in G8 Directional Solidification Silicon Ingot Growth

Oxygen precipitation in Czochralski silicon annealed at 450°C under a high pressure of 1 GPa

Grown-in defects in heavily phosphorus-doped Czochralski silicon