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

Materials with good flexibility and high conductivity that can provide electromagnetic interference (EMI) shielding with minimal thickness are highly desirable, especially if they can be easily processed into films. Two-dimensional metal carbides and nitrides, known as MXenes, combine metallic conductivity and hydrophilic surfaces. Here, we demonstrate the potential of several MXenes and their polymer composites for EMI shielding. A 45-micrometer-thick Ti3C2Tx film exhibited EMI shielding effectiveness of 92 decibels (>50 decibels for a 2.5-micrometer film), which is the highest among synthetic materials of comparable thickness produced to date. This performance originates from the excellent electrical conductivity of Ti3C2Tx films (4600 Siemens per centimeter) and multiple internal reflections from Ti3C2Tx flakes in free-standing films. The mechanical flexibility and easy coating capability offered by MXenes and their composites enable them to shield surfaces of any shape while providing high EMI shielding efficiency.

Electromagnetic interference shielding with 2D transition metal carbides (MXenes)

Metal Oxides and Oxysalts as Anode Materials for Li Ion Batteries

Conductometric semiconducting metal oxide gas sensors have been widely used and investigated in the detection of gases. Investigations have indicated that the gas sensing process is strongly related to surface reactions, so one of the important parameters of gas sensors, the sensitivity of the metal oxide based materials, will change with the factors influencing the surface reactions, such as chemical components, surface-modification and microstructures of sensing layers, temperature and humidity. In this brief review, attention will be focused on changes of sensitivity of conductometric semiconducting metal oxide gas sensors due to the five factors mentioned above.

Metal oxide gas sensors: Sensitivity and influencing factors

We developed two-step solution-phase reactions to form hybrid materials of Mn3O4 nanoparticles on reduced graphene oxide (RGO) sheets for lithium ion battery applications. Mn3O4 nanoparticles grown selectively on RGO sheets over free particle growth in solution allowed for the electrically insulating Mn3O4 nanoparticles wired up to a current collector through the underlying conducting graphene network. The Mn3O4 nanoparticles formed on RGO show a high specific capacity up to ~900mAh/g near its theoretical capacity with good rate capability and cycling stability, owing to the intimate interactions between the graphene substrates and the Mn3O4 nanoparticles grown atop. The Mn3O4/RGO hybrid could be a promising candidate material for high-capacity, low-cost, and environmentally friendly anode for lithium ion batteries. Our growth-on-graphene approach should offer a new technique for design and synthesis of battery electrodes based on highly insulating materials.

Mn3O4-Graphene Hybrid as a High Capacity Anode Material for Lithium Ion Batteries

Nd3+ doped PbZr0.52Ti0.48O3 (PNZT) nanopowders were prepared by sol-gel methods in ethylene glycol system. Neodymium nitrate was used as Nd3+ source. The reaction mechanisms of nanopowder preparing process from the sol were discussed through using FTIR, XRD, TG-DTA, and it was proved that the heating temperature of PNZT was 50degC-100degC higher than PZT. PNZT lattice structure was characterized by XRD, Raman, SEM and TEM. Results show that the lattice aberrance of PNZT was increased with Nd3+ doping. Comparing with PZT, the constant a and V of PNZT were decreasing with the addition of Nd3+, but the c and c/a were increasing with a few Nd3+ doping and then were decreasing gradually with the addition of Nd3+. If Nd3+% les 9% (mol), perovskite PNZT nanopowders which particle size is about 20-50 nm could be formed. Nd3+ replaced Pb2+ of PZT and formed steady perovskite crystal with Ti4+ and O2-

Sol-Gel Synthesis and Characterization of Nd3+ Doped PZT Nanopowders Using a Novel System

With the advent of intelligent society and the popularity of electronic equipment, the protection and treatment of electromagnetic (EM) radiation have become hot research topics all over the world. Herein, novel 2D carbon-based nanoplates with uniformly embedded Co nanoparticles are prepared, with unique hierarchical structure and integrated magnetic-dielectric components. The obtained hierarchical nanoplates exhibit a wide range of tunable EM properties (ε' for 3.38 to 34.67 and ε″ for 0.13 to 31.45) by manipulating the dispersed states inside wax system, which can achieve an effective switch from microwave absorption to EM interference shielding performance. The optimal reflection loss reaches -55.6 dB, and the shielding efficiency is 93.5%. Meanwhile, the hierarchical nanoplates also exhibit impressive capacitive performance, with a specific capacitance of 1654 F g-1 at 1 A g-1 . Based on this, a creative device is constructed with the nanoplates, which can convert harmful EM radiation to useful electric energy for recycling. This work offers a new idea for the development of EM materials and functional devices, powerfully promoting the advance of energy and environmental fields.

Thermally Derived Hierarchical Nanoplates for Electromagnetic Protection and Waste Energy Recovery Device.

Zn2GeO4–ZnO crystals with base diameter of approximately 400 nm and height of 400–800 nm were successfully prepared by a facile combustion oxidation at 960°C. No catalyst or carrier gases were used. XRD, SEM and SPM analysis revealed that Zn2GeO4 and ZnO have grown to micro–nanometer screws–cone–like parasitic crystals, and they showed obvious surface traces of spiral growth. SPAM examination showed that the section fine lines reticular was contained in the inside of the as–prepared crystals. The spiral growth process were proposed. The photocatalytic activity experiment indicated that the photocatalytic activity of the Zn2GeO4–ZnO crystals was significantly higher than that of nano–tetrapod ZnO.

Facile Preparation, Characterization and Photocatalytic Performance of Micro–nanometer Zn2GeO4–ZnO Screws–Cone–like Parasitic Crystals

Pb(Zr0.52Ti0.48)O3 thick films embedded with ZnO nanoneedles (PZT–ZnOn) were successfully prepared on Pt/Cr/SiO2/Si substrates by the hybrid sol–gel method via spin-coating ZnOn suspension and lead zirconate titanate (PZT) sol. To control the orientation of the films, a PbTiO3 (PT) layer was first deposited as a seed layer. Effects of annealing method and ZnOn contents on the corresponding orientation and crystallization of PZT–ZnOn films were investigated by XRD and SEM. The results show that all the PZT–ZnOn composite thick films have pure perovskite structure and high-quality film surface. The dielectric and ferroelectric properties of the PZT–ZnOn films are close to the PZT films, and have a little decrease with the increasing of the ZnOn contents.

Mao-Sheng Cao

Papers

Sol-Gel Synthesis and Characterization of Nd3+ Doped PZT Nanopowders Using a Novel System

Thermally Derived Hierarchical Nanoplates for Electromagnetic Protection and Waste Energy Recovery Device.

Facile Preparation, Characterization and Photocatalytic Performance of Micro–nanometer Zn2GeO4–ZnO Screws–Cone–like Parasitic Crystals

Synthesis and electrical properties of Pb(Zr 0.52 Ti 0.48 )O 3 thick films embedded with ZnO nanoneedles prepared by the hybrid sol–gel method

Making method of micro-electro-mechanical V-type micro valve