[신간의 별자리x] 우리/미술, 그리고 ‘슬픔의 박물관’

The term photonic crystals appears because of the analogy between electron waves in crystals and the light waves in artificial periodic dielectric structures. During the recent years the investigation of one-, two-and three-dimensional periodic structures has attracted a widespread attention of the world optics community because of great potentiality of such structures in advanced applied optical fields. The interest in periodic structures has been stimulated by the fast development of semiconductor technology that now allows the fabrication of artificial structures, whose period is comparable with the wavelength of light in the visible and infrared ranges.

http://ieeexplore.ieee.org/iel5/6354/16969/00781867.pdf

Photonic crystals

II. Structure of Perovskites 1982 A. Crystal Structure 1982 B. Nonstoichiometry in Perovskites 1983 1. Oxygen Nonstoichiometry 1983 2. Cation Nonstoichiometry 1984 C. Physical Properties 1985 D. Adsorption Properties 1986 1. CO and NO Adsorption 1986 2. Oxygen Adsorption 1987 E. Specific Surface and Porosity 1987 F. Thermal Stability in a Reducing Atmosphere 1989 III. Acid−Base and Redox Properties 1990 A. Acidity and Basicity 1990 B. Redox Processes 1991 1. Kinetics and Mechanisms 1992 2. Reduction−Oxidation Cycles 1993 C. Ion Mobility 1993 1. Oxygen Transport 1993 2. Cation Transport 1994 IV. Heterogeneous Catalysis 1995 A. Oxidation Reactions 1995 1. CO Oxidation 1995 2. Oxidation of Hydrocarbons 1996 B. Pollution Abatement 2001 1. NOx Decomposition 2001 2. Exhaust Treatment 2002 3. Stability 2004 C. Hydrogenation and Hydrogenolysis Reactions 2004 1. Hydrogenation of Carbon Oxides 2004 2. Hydrogenation and Hydrogenolysis Reactions 2006

Chemical structures and performance of perovskite oxides.

Nanoparticles (NPs) are increasingly used to target bacteria as an alternative to antibiotics. Nanotechnology may be particularly advantageous in treating bacterial infections. Examples include the utilization of NPs in antibacterial coatings for implantable devices and medicinal materials to prevent infection and promote wound healing, in antibiotic delivery systems to treat disease, in bacterial detection systems to generate microbial diagnostics, and in antibacterial vaccines to control bacterial infections. The antibacterial mechanisms of NPs are poorly understood, but the currently accepted mechanisms include oxidative stress induction, metal ion release, and non-oxidative mechanisms. The multiple simultaneous mechanisms of action against microbes would require multiple simultaneous gene mutations in the same bacterial cell for antibacterial resistance to develop; therefore, it is difficult for bacterial cells to become resistant to NPs. In this review, we discuss the antibacterial mechanisms of NPs against bacteria and the factors that are involved. The limitations of current research are also discussed.

/pdf/the-antimicrobial-activity-of-nanoparticles-present-455xafgyws.pdf

The antimicrobial activity of nanoparticles: present situation and prospects for the future

Tubular and fibrous nanostructures of titanates have recently been
synthesized and characterized. Three general approaches (template assisted, anodic oxidation, and alkaline hydrothermal) for the preparation of nanostructured titanate and TiO2 are reviewed. The crystal structures, morphologies, and mechanism of formation
of nanostructured titanates produced by the alkaline hydrothermal method are critically discussed. The physicochemical properties of nanostructured titanates are highlighted and the links between properties and applications are emphasized. Examples of early applications of nanostructured titanates in catalysis, photocatalysis, electrocatalysis, lithium batteries, hydrogen storage, and solar-cell technologies are reviewed. The stability of titanate nanotubes at elevated temperatures and in acid media is considered.

Protonated Titanates and TiO2 Nanostructured Materials: Synthesis, Properties, and Applications

Flexible artificial synapses, a conjunctive product of brain‐inspired neuromorphic computing and wearable electronics, arouse enormous interest in highly connected and energy‐efficient neural networks. The organic–inorganic hybrid materials hold great potential in flexible devices due to versatile properties. Here, an organic–inorganic hybrid synaptic device consisting of 2 nm Al2O3 and 22 nm Al‐based hydroquinone (Al‐HQ) sandwiched between Pt and poly(3,4‐ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS) electrodes is prepared on highly flexible cellophane by molecular/atomic layer deposition (MLD/ALD). The vertically integrated Pt/Al2O3/Al‐HQ/PEDOT:PSS device exhibits reliable resistive switching with an ON/OFF ratio greater than 103. Several important bio‐synaptic functions, such as long‐term potentiation, long‐term depression, paired‐pulse facilitation, and spike‐time‐dependent plasticity, are realized in this device with the extremely low energy consumption of ≈25.2 fJ per reset operation, which is ascribed to the unique electron trapping/detrapping and tunneling mechanism. Remarkably, the excellent flexibility and robustness of this hybrid synaptic device is confirmed under the minimum curvature radius of ≈0.7 mm after 104 bending cycles. A pattern recognition computation based on these hybrid synapse devices shows a 90.2% learning accuracy. This research paves a way for the MLD/ALD‐derived organic–inorganic‐hybrid‐based artificial synapse applications in flexible energy‐efficient neuron network systems toward system‐on‐plastics.

Ultraflexible and Energy‐Efficient Artificial Synapses Based on Molecular/Atomic Layer Deposited Organic–Inorganic Hybrid Thin Films

Surface Reaction Mechanism of Atomic Layer Deposition of Titanium Nitride Using Tetrakis(dimethylamino)titanium and Ammonia

Strain sensors have attracted tremendous attention in healthcare monitoring and human–computer interaction due to their great potential in intelligent equipment. However, conventional strain sensors cannot possess high sensitivity, wide stretchable range, and low limit of detection (LoD) at the same time. Here, an ultrasensitive wearable strain sensor over a broad range based on the simple parallel connection architecture of Ir‐nanoparticles‐modified carbon nanotubes (Ir NPs@CNTs) and two Pt layers using a reticular patterned polymer substrate (Dragon Skin 30, (DS)) is reported. It exhibits an extremely high gauge factor of 13 590, broader strain range up to 98%, lower LoD of 0.02% strain, faster response time of 134 ms, and long‐term durability above 18 000 cycles. The mechanisms of performance improvement are proposed based on the synergistic and hierarchical effects of the combined sandwich structures by parallel connection on patterned DS, including geometric effect, crack formation/propagation in parallel grooves, and tunneling‐based charge carriers between IrNPs and IrNPs/CNTs. By introducing a metal nanolayer, the sensor also shows heat sensitivity at various environmental temperatures. The wearable sensors have been utilized for human‐motion detection with improved comprehensive performance, indicating their promising applications in flexible electronics and artificial intelligent fields.

Extremely Sensitive Wearable Strain Sensor with Wide Range Based on a Simple Parallel Connection Architecture

The SrBi2Ta2O9 (SBT) thin films were prepared by metalorganic decomposition on Pt/TiO2/SiO2/Si substrates with rapid thermal annealing (RTA). The films were annealed at different temperature (T) for different time (t) to investigate the crystal growth of the films. The grain size distribution basically conforms to Gaussian distribution and the rate of nucleation is high with RTA. There are two steps in grain growth. First, grain size is proportion to t1/2 before 10s, then proportion to t1/2. The growth activity energy is about 29kJ/mol under 700°C and 81kJ/mol above 700°C. From the results mentioned above we can draw a conclusion that it is easier to grow larger SBT grains by increasing annealing temperature than by lengthening annealing time in RTA.

Growth and characterization of SrBi2Ta2O9 thin films prepared by rapid thermal annealing

Hafnium-based dielectrics have been extensively investigated as a possible replacement for SiO 2 . Anhydrous Hf/Zr mixed-metal nitrate precursor Hf x Zr 1−x (NO 3 4 (HZN) was successfully synthesized and hafnium zirconate (Hf x Zr 1− O 2 ) thin films were prepared by the chemical vapor deposition (CVD) technique from this precursor. The basal dielectric properties of Hf x Zr 1− O 2 films were studied, and C-V curves with negligible hysteresis are achieved.

Aidong Li

Papers

Ultraflexible and Energy‐Efficient Artificial Synapses Based on Molecular/Atomic Layer Deposited Organic–Inorganic Hybrid Thin Films

Surface Reaction Mechanism of Atomic Layer Deposition of Titanium Nitride Using Tetrakis(dimethylamino)titanium and Ammonia

Extremely Sensitive Wearable Strain Sensor with Wide Range Based on a Simple Parallel Connection Architecture

Growth and characterization of SrBi2Ta2O9 thin films prepared by rapid thermal annealing

Properties of Hf 0.7 Zr 0.3 O 2 thin films chemical vapor deposited using a single-source precursor of anhydrous Hf x Zr 1−x (NO 3 4 precursors