With an aim to develop novel Cu–Zn alloys with high mechanical properties, in this study, Ni and Si elements were added to Cu–10Zn and Cu–20Zn alloys, and four kinds of Cu–Zn alloys were synthesized through gravity casting. The effect of the addition of Ni and Si on the microstructure and mechanical properties has been systematically investigated. Results revealed that the addition of Ni and Si not only refined the microstructure but also played significant roles to improve the mechanical properties of Cu–Zn alloys; δ-Ni2Si precipitates were formed in the Cu–20Zn–1.5Ni–0.34Si alloy, which obeyed a crystal orientation relationship of (001)Cu‖(001)δ and [110]Cu‖[100]δ. As compared with the Cu–20Zn alloy, the tensile strength of the studied Cu–20Zn–1.5Ni–0.34Si alloy was increased from 373.2 MPa to 776.4 MPa, and the yield strength increased from 242.1 MPa to 718.4 MPa. Operative strengthening mechanisms in the Cu–20Zn–1.5Ni–0.34Si alloy with different thermal-mechanical treatment states will be discussed in detail with the aim to draw a new strategy to develop high strength brass alloys.

The exaggerated grain growth, anisotropic crystallite morphology, and thermal expansion are the main reasons for the microcracking of sintered TiB2, wherein grain coarsening and anisotropic crystallite morphology are believed to be controlled by the surface stabilities of TiB2. To deeply understand the grain growth mechanism, the anisotropic stability and bonding features of TiB2 surfaces, including $\left( {11\bar 20} \right)$ , two types of (0001), and three types of $\left( {10\bar 10} \right)$ , are investigated by first-principles calculations. By employing the two-region modeling method, surface energies are calculated and the $\left( {11\bar 20} \right)$ surface is found to be more stable than (0001) and $\left( {10\bar 10} \right)$ surfaces. Hexagonal plate-like grain morphology is predicted. The different bonding conditions of surface Ti and B atoms contribute to the difference of surface structure relaxation between surfaces with Ti- and B-termination, which lead the B-terminated ones to be more stable. It is also found that the surface energies of TiB2 are much higher than those of ZrB2 with a similar structure, which may be responsible for the easy coarsening of TiB2.

In this study, the time that molten magnesium is in contact with the aluminum insert before solidification was predicted by solving the conservation equations of mass, momentum, and energy during compound casting of dissimilar Al/Mg couples. For this purpose, a three-dimensional transient model and FLOW-3D software were utilized and distributions of temperature and velocity vectors in the fluid over time were obtained. Then, the contact time at the bottom, middle, and top of aluminum insert in its interface with the magnesium melt was calculated. The results of simulation show that the contact time decreases from about 1.7 s at bottom to 1.6 s at middle and 0.8 s at top of the interface, respectively. This is consistent with the experimental metallographic observations which indicate a decrease in the thickness of formed intermetallic compounds from bottom to middle and top of the Al/Mg interface.

The erosion behavior of a directionally solidified Fe–B alloy containing 3.5 wt% B in the different velocities of flowing liquid zinc is investigated by X-ray diffraction and scanning electron microscopy to clarify the effect of interaction between Fe2B and the erosion products on erosion performance using a rotating-disk technique. The results indicate that the Fe–B alloy erodes at a low and steady rate in flowing liquid zinc. The microstructure of erosion layers of the directionally solidified Fe–B alloy depends on the orientation relation between the growth direction of Fe2B phase and the erosion surface. When the growth direction of Fe2B is perpendicular to the erosion surface, the Fe2B and the erosion compounds form a compact and stable combining layer that effectively inhibits the erosion of flowing liquid zinc and further improves the erosion resistance of Fe–B alloy.

The NiAl matrix composite coatings containing silver and molybdenum were prepared by atmospheric plasma spraying and their tribological properties were investigated in details from 25 to 900 °C. The X-ray diffraction (XRD), micro-Raman, scanning election microscopy (SEM) and transmission election microscopy (TEM) were used to analyze the composition and microstructure of composite coatings. The X-ray diffraction (XRD) results shown that molybdenum and silver were exist in single-phase, but not alloyed in composite coatings. The addition of silver could effectively improve the tribological properties of composite coatings at the wide range of temperature. The silver, nickel and molybdenum could occur the tribo-chemical reaction and form silver molybdates and nickel molybdates lubricating films inside the wear track of composite coatings at high temperature. The friction process promoted the formation of the silver molybdates. The silver molybdates, nickel molybdates and NiO were the main components in composite coatings at high temperature, which could effectively improve tribological properties of composite coatings.

In recent years, stimuli responsive polymer based gene delivery vehicle design for cancer treatment and treatment of other genetic disorders has received extensive attention. Early studies focusing on DNA delivery have been facilitated by functional polymers and this area has seen further growth spurred by recent gene silencing strategies developed for small RNA [i.e., small interfering RNA (siRNA) or micro RNA (miRNA)] delivery. DNA and small RNAs possess analogous properties; however, their explicit differences define the specific challenges associated with the delivery route and the design of functional materials to overcome distinct challenges. Apart from classical gene delivery, the recent advances in genome editing have revealed the necessity of new delivery devices for genome editing tools. A system involving CRISPR (clustered, regularly interspaced, short palindromic repeats) and an endonuclease CRISPR-associated protein 9 (Cas9) coupled with a short, single-guide RNA (sgRNA) has emerged as a promising tool for genome editing along with functional delivery systems. For all these nucleic acid based treatments, the internal or external physiochemical changes in the biological tissue/cells play a major role in the design of stimuli responsive delivery materials for both in vitro and in vivo applications. This review emphasizes the recent advances in the use of pH, temperature, and redox potential-responsive polymers overcoming hurdles for delivery of gene and gene editing tools for both in vitro and in vivo applications. Specifically the chapter focuses on recently proposed delivery strategies, types of delivery systems, and polymer synthesis/modification methods. The recent advances in CRISPR/Cas9-sgRNA technology and delivery are also described in a separate section. The review ends with current clinical trials, concluding remarks, and future perspectives.

Freeze casting of traditional ceramic suspensions and freeze casting of preceramic polymer solutions were directly compared as methods for processing porous ceramics. Alumina and polymethylsiloxane were freeze cast with four different organic solvents (cyclooctane, cyclohexane, dioxane, and dimethyl carbonate) to obtain ceramics with ∼70% porosity. Median pore sizes were smaller for solution freeze casting than for suspension freeze casting under identical processing conditions. The pore structures, which range from foam-like to lamellar, were correlated to the Jackson α-factor of the solvent; solvents with low α-factors yielded nonfaceted pore structures, while high α-factors produced more faceted structures. Intermediate α-factors resulted in dendritic pore structures and were most sensitive to the processing method. Small suspended particles ahead of a solid–liquid interface are hypothesized to destabilize the dendrite tip in suspension freeze casting resulting in more foam-like structures. Differences in processing details were highlighted, particularly regarding the improved freezing front observation possible with solution-based freeze casting.

Precipitates and grain sizes in non-oriented silicon steel samples, which were hot-rolled (HR), continuously annealed (CA), and stress-relief-annealed (SA), were characterized using scanning electron microscopy (SEM) equipped with electron back-scattered diffraction. The average grain sizes of the HR, CA, and SA samples were 28, 46, and 46 μm, respectively. SEM observations revealed that the precipitates were mainly dispersed inside grains in the HR and the CA samples, but mainly at grain boundaries in the SA sample. The density of precipitates was highest in the SA sample and lowest in the HR sample. Precipitates at the grain boundaries, which were identified as manganese sulfides, were nearly spherical, their diameter ranging from 0.3 to 0.7 μm. We calculated the pining force exerted by grain-boundary precipitates and found that it outweighed the driving force of the grain growth that was controlled by boundary curvature.

We report a novel approach to the instantaneous photoinitiated synthesis of mixed anatase-rutile nanocrystalline TiO2 thin films with a three-dimensional nanostructure through pulsed white light irradiation of photosensitive Ti-organic precursor films. Pulsed photoinitiated pyrolysis accompanied by instantaneous self-assembly and crystallization occurred to form graphitic oxides-coated TiO2 nanograins. Subsequent pulsed light irradiation working as in situ pulsed photothermal treatment improved the crystalline quality of TiO2 film despite its low attenuation of light. The non-radiative recombination of photogenerated electrons and holes in TiO2 nanograins, coupled with inefficient heat dissipation due to low thermal conductivity, produces enough heat to provide the thermodynamic driving force for improving the crystalline quality. The graphitic oxides were reduced by pulsed photothermal treatment and can be completely removed by oxygen plasma cleaning. This photoinitiated nanofabrication technology opens a promising way for the low-cost and high-throughput manufacturing of nanostructured metal oxides as well as TiO2 nanocrystalline thin films.

We report results of the studies relating to the fabrication of nanostructured zirconia (nZrO2) based immunosensor for cardiac troponin I biomarker (acute myocardial infarction) detection. One step, low temperature hydrothermal process was used for the synthesis of nZrO2 (∼5 nm). This nZrO2 was functionalized with 3-aminopropyl triethoxy silane (APTES) and thereafter it was electrophoretically deposited on to indium tin oxide (ITO) coated glass electrode. EDC/NHS surface chemistry was used for covalent immobilization of monoclonal anti-troponin-I (anti-cTnI) antibodies onto APTES/nZrO2/ITO electrode. The structural, morphological and functional characterization of the synthesized nanoparticles and the fabricated immunoelectrode were conducted via X-ray diffraction (XRD), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), and electrochemical techniques. The results of electrochemical response studies of BSA/anti-cTnI/APTES/nZrO2/ITO immunoelectrode reveal that, this platform can be used for efficient detection of cardiac troponin I (cTnI) biomarker with a wide linear detection range (0.1–100 ng/mL) and sensitivity [3.9 µA mL/(ng cm2)].

Mechanical stability of Ag and Cu printed and evaporated metallization lines on polymer substrates is investigated by means of monotonic tensile and cyclic bending tests. It is shown that lines which demonstrate good performance during monotonic tests fail at lower strains during a cyclic bending tests. Evaporated lines with the grain size of several hundreds of nanometers have good ductility and consequently good stability during monotonic loading but at the same time they fail at low strains during cyclic bending. Printed lines with nanocrystalline microstructure, in contrast, demonstrate more intensive cracking during monotonic loading but higher failure strains during cyclic bending. Apart from the grain size effect, the effect of film thickness on the saturation crack density after cyclic bending is also demonstrated. Thinner films have higher crack density in accordance with the shear lag model.

We report on the intermediate-temperature synthesis (973 K) and operation (<750 K) of Ce4.67(SiO4)3O-based thin-film oxy-apatites. The apatite thin films show the high conductivity of ~0.05–0.5 S/cm and excellent stability in reducing atmosphere (<10−17 atm), which makes promising these materials as anodes for intermediate-temperature solid oxide fuel cell (SOFC) application. The proto-type SOFCs implementing single-layer apatite and apatite/Pt bilayer anodes were fabricated and the resulting performance (e.g., peak power density of ~5 mW/cm2 at 748 K) presents notable feasibility of ZCS-based oxy-apatite anodes for thin-film SOFC devices.

Composite copper oxide–copper bromide films were electrodeposited on gas diffusion layer (GDL) supports under controlled potential from aqueous copper salt solutions in the presence of a complexing/surfactant agent such as lactate. The solution pH was adjusted to target simultaneous deposition of cubic nanostructures composed of copper, oxygen, and bromine elements. The film composition and morphology were carefully tuned for enhanced electrochemical conversion of CO2 to hydrocarbons. Hydrocarbon products, predominantly ethylene and minor amounts of methane, ethane, and propylene were observed along with inevitable H2 co-generation. Importantly, CO gas was not detected during CO2 electrolyses. Low temperatures (3–5 °C) enhanced the conversion of CO intermediate to C2H4. The durability and electroactivity of these composite films were maintained for extended periods (up to 10 h) of CO2 electrolysis by periodic in situ application of anodic pulses to regenerate the cathode surface.

Shape memory alloys (SMAs) are unique class of smart materials with excellent physical, mechanical and biomedical properties, which have wide applications in several fields such as aerospace, robotics, biomedical, and dental etc. These alloys are well known for exhibiting shape memory effect (SME) and pseudoelasticity (PE), it is a well-established fact that they are required to be processed into functioning parts. The conventional machining affects the internal properties of shape memory alloys and hence, it is reported that nonconventional machining techniques are more suitable. Wire electro discharge machining (WEDM) is one of the nonconventional machining processes for machining complicated shapes without hampering the internal properties of such type of materials. In the present experimental investigation, wire electro discharge machining of Ti50Ni40Co10 shape memory alloy (SMA) has been carried out and machining performances such as surface roughness (SR), and material removal rate (MRR) have been evaluated. Experimental results exposed that pulse on time, pulse off time and servo voltages are most influential process parameters on the responses. The machined surface has been characterised with respect to microstructure, microhardness, and phases formed.

This article features the recent developments in fluorographene (FG) and its other functional forms such as fluorographene oxide—their synthesis, fluorination, defluorination, and applications. FG is identified as an important functional derivative of graphene, and FG’s multifunctionalities make it as an ideal candidate for diverse fields, say from photovoltaic to bio-medical diagnosis, imaging, sensing, and therapy. Here the possibilities of FG as a biomedical sensing platform is discussed in detail and the potentials of FG based electrochemical and conductometric sensing platforms are unraveled. The importance of fluorine control as well as the other key factors need to be considered while choosing FG based bio-sensing platforms are also discussed.

Sodium-ion batteries (SIBs) have received intensive attentions owing to the abundant and inexpensive sodium (Na) resource. Layered vanadium oxides are featured with various valence states and corresponding compounds, and through multi-electron reaction they are capable to deliver high Na storage capacity. The rational construction of unique structures is verified to improve their Na storage properties. This perspective provides an overview of recent advances in layered vanadium oxide for SIBs, with a particular focus on construction of novel nanostructures, and mechanism studies via in situ characterization. Finally, we predict possible breakthroughs and future trends that lie ahead for high-performance layered vanadium oxides SIBs cathode.

It is important to fabricate iron-based nitride/conductive material composite to obtain good catalytic performance. In this work, Fe2N nanoparticles with diameter of approximately 30 nm have been successfully dispersed on the surface of nitrogen-doped graphite oxide (NrGO) by a facile sol–gel method and further ammonia atmosphere treatment. XPS, XRD, Raman, and TEM proved that Fe2N nanoparticles are well monodispersed, and nitrogen atoms are doped in NrGO. The composite possessed two merits, that is, the more catalytic active site in Fe2N nanoparticles due to the well monodispersion, and fast electron transfer due to the nitrogen dope in rGO. With the proper ratio, the composite exhibited brilliant catalytic activity and durability in acidic media. It possesses overpotential of 94 mV to approach 10 mA/cm2, a small Tefel slope of 49 mV/dec, and maintains the good electrocatalytic activity for 10 h. Cyclic voltammetry and electrochemical impedance spectroscopy indicated that the electrocatalyst possessed high catalytic active area and fast electron transfer. Our work may provide a new avenue for the preparation of low-cost iron-based nitride/NrGO composite for highly efficient electrochemical hydrogen evolution.

Selective laser melting (SLM) technology efficiently solves the current manufacturing challenges of high-performance porous structure components, due to its freeform fabrication principle. As the most basic and crucial structure element, the nodes of porous structure component play an important role in its mechanical property. In this study, finite element method was used to investigate the thermal behavior during SLM processing of micro-scale node-structure. The dynamic size of molten pool was continuously predicted and consequently the typical “necking” effect was found, which was consistent with the experiment results. Besides, the influence of laser scan speed on temperature and temperature gradient of molten pool was also analyzed. The results indicated that the “necking” effect became more conspicuous with the applied scan speed increasing, which significantly deteriorated the mechanical property of porous structure components.