Topic Review
Concentration Cells Corrosion
In marine environments, microbial attacks on metallic materials result in microbiologically influenced corrosion (MIC), which could cause severe safety accidents and high economic losses. To date, MIC of a number of metallic materials ranging from common steels to corrosion-resistant ferrous alloys has been reported. The MIC process has been explained based on (1) bio-catalyzed oxygen reduction; (2) kinetics alternation of the corrosion process by increasing the mass transport of the reactants and products; (3) production of corrosive substances; and (4) generation of auxiliary cathodic reactants.
  • 798
  • 16 Sep 2022
Topic Review
Uranyl Carbonate Minerals
Uranyl carbonates are one of the largest groups of secondary uranium(VI)-bearing natural phases being represented by 40 minerals approved by the International Mineralogical Association, overtaken only by uranyl phosphates and uranyl sulfates. Uranyl carbonate phases form during the direct alteration of primary U ores on contact with groundwaters enriched by CO2, thus playing an important role in the release of U to the environment. The presence of uranyl carbonate phases has also been detected on the surface of “lavas” that were formed during the Chernobyl accident.
  • 790
  • 24 Jun 2021
Topic Review
Shot Peening and Cavitation Peening
Shot peening is a dynamically developing surface treatment used to improve the surface properties modified by tool, impact, microblasting, or shot action.
  • 774
  • 08 Apr 2022
Topic Review
Scanning Electrochemical Microscopy Applied to Metals and Coatings
Scanning electrochemical microscopy (SECM) is a scanning probe microscope (SPM) technique based on electrochemical principles that allows chemical imaging of materials with spatial resolution. The movement of a microelectrode (ME) in close proximity to the interface allows the application of various experimental procedures that can be classified into amperometric and potentiometric operations depending on either sensing faradaic currents or probe potential values due to concentration distributions resulting from the corrosion process, as sketched in. In addition, alternating current signals can be applied to the ME, leading to AC-operation modes.
  • 770
  • 23 May 2022
Topic Review
Defect-Related Etch Pits on Crystals and Their Utilization
Etch pits could form on an exposed surface of a crystal when the crystal is exposed to an etching environment or chemicals. Due to different dissolution rates along various crystalline directions in a crystal, the dissolution process is anisotropic; hence, etch pits usually have a regular shape. The morphology, size, and density of etch pits can be affected by various factors, including the chemical composition of the etchant, etching time, etching temperature, status of the matrix, and so on. Traditionally, etch pits are utilized to evaluate the dislocation density and some defect-related properties. Now, in the modern fabrication industries, the relationship between etch pits and defects has been utilized more skillfully. High-quality crystals can be fabricated by controlling dislocations revealed by etch pits. Meanwhile, with the as-revealed dislocation as the diffusion path of atoms, new crystals will emerge in corresponding etch pits.
  • 725
  • 11 Nov 2022
Topic Review
MXenes—A New Class of Two-Dimensional Materials
A new class of two-dimensional nanomaterials, MXenes, which are carbides/nitrides/carbonitrides of transition and refractory metals, has been critically analyzed. Since the synthesis of the first family member in 2011 by Yury Gogotsi and colleagues, MXenes have quickly become attractive for a variety of research fields due to their exceptional properties. Despite the fact that this new family of 2D materials was discovered only about ten years ago, the number of scientific publications related to MXene almost doubles every year. Thus, in 2021 alone, more than 2000 papers are expected to be published, which indicates the relevance and prospects of MXenes. 
  • 724
  • 28 Mar 2022
Topic Review
Hypopigmentation Mechanisms of Anti-Tyrosinase Peptides from Food Proteins
Skin hyperpigmentation resulting from excessive tyrosinase expression has long been a problem for beauty lovers, which has not yet been completely solved. Although researchers are working on finding effective tyrosinase inhibitors, most of them are restricted, due to cell mutation and cytotoxicity. Therefore, functional foods are developing rapidly for their good biocompatibility. Food-derived peptides have been proven to display excellent anti-tyrosinase activity, and the mechanisms involved mainly include inhibition of oxidation, occupation of tyrosinase’s bioactive site and regulation of related gene expression. For anti-oxidation, peptides can interrupt the oxidative reactions catalyzed by tyrosinase or activate an enzyme system, including super-oxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GSH-Px) to scavenge free radicals that stimulate tyrosinase. In addition, researchers predict that peptides probably occupy the site of the substrate by chelating with copper ions or combining with surrounding amino acid residues, ultimately inhibiting the catalytic activity of tyrosinase.
  • 719
  • 06 May 2022
Topic Review
NiO-TiO2 p-n Heterojunction
NiO is a typical p-type semiconductor and it has widely been combined with TiO2 to form the p-n heterojunction due to its suitable energy band structure, high charge carrier concentration, high chemical stability and low cost. Decreasing the size of NiO to nanoclusters helps to improve the electron transfer channels on the surface of TiO2, thus enhance photocatalytic hydrogen production efficiency.
  • 715
  • 19 Apr 2022
Topic Review
Si-Based GeSn
A literature survey revealed that GeSn materials have numerous potential applications, including Si-based, integrated high-efficiency light sources; high-mobility electronic devices; low-cost Si-based high-performance shortwave infrared (SWIR) imaging sensors; Si-based photovoltaics; optical signal encoding in the mid-infrared range; high-performance logic applications; Si-based integrated thermoelectrics as wearable devices; Si-based spintronics; Si-based integrated reconfigurable dipoles; and Si-based quantum computing. GeSn-related fundamental research and development applications have also been extensively investigated. 
  • 713
  • 14 Mar 2022
Topic Review
Development of Fencing Blade Materials
Using two fencing swords manufactured in Europe and China, we investigated the typical materials used for fencing blades and compared the experimental results with the nominal compositions of a variety of steels. By combining the requirements for the safety of athletes, mechanical behaviors of different steels, and production costs for industry, there is possible directions for the heat treatments and processing methods that have the potential to enhance performance and overcome the limitations of previous materials. 
  • 695
  • 17 Feb 2022
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