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These nanostructured films are templated by surfactants like alkyltrimethylammonium salts producing structures of various symmetries including worm-like disordered, lamellar, 2D-hexagonal (p6mm), 3D-hexagonal (p63/mmc) and cubic (pm3n) with varied pore dimensions [2, 3, 4, 5, 6, 7].
The derived hierarchical structures combine the mechanical strength of the inorganic framework while the organic component offers convenient processing feasibility.
The chemical structure and properties of cresol red dye are listed in Fig. 1
Chemical structure and properties of cresol red dye.
Innocenzi, Mesoporous Hybrid Thin Films: The Physics and Chemistry Beneath, Chem.

In physical chemistry, the fluidity is defined as the inverse of the viscosity [10], but it is expressed with measures not easily intuitive and practically usable in foundry.
These fragments/nuclei grow into new grains to the point at which they start to impinge on each other, becoming suddenly much more resistant to flow and resulting in an equiaxed structure.
Figure 9 shows the grain structure of the A356 alloy in the region of the tip of the fluidity spirals.
Finer and homogeneous grain structure with no columnar grains are revealed throughout, with distributed microshrinkage.
Typical grain structure of AlSi7Mg alloy at the tip of the fluidity spiral.

Characterization of Cooling Rate and Microstructure of Rapidly Solidified Spherical Mono-Sized Sn-1.0Ag-0.5Cu Particles Ying-Yan Hu1,2*, Jun-Feng Wang2, Can Li2,4, Jian-Qiang Li2,3* 1School of Engineering and Technology, China University of Geosciences, Beijing 100083, China 2National Engineering Laboratory for Hydrometallurgical Cleaner Production Technology, Key Laboratory of Green Process and Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, China 3School of Chemistry and Chemical Engineering, University of Chinese Academy of Sciences, Beijing 100049, China 4School of Materials Science and Engineering, Wuhan University of Technology, Wuhan 430070, China *Corresponding author: Ying-yan Hu, Email yyhu@ipe.ac.cn; Jian-qiang Li, Email jqli@ipe.ac.cn.
The crystal structure of microspheres was determined by X-ray diffraction (XRD) (Empyeam, PANalytical B.
Figure 4 exposes the internal structure of a Sn-1.0Ag-0.5Cu particle with diameter 263.5 μm.
According to the properties of the liquid–solid interface, the Sn-1.0Ag-0.5Cu alloy is the metal–metal eutectic structure, and the type of interface contact is rough–rough, so it is easy to form the eutectic structure.

In general, the structure (morphology, scale, distribution) of Pb-free solders may be strongly influenced by altered growth conditions.
Furthermore, thermal processing variables play an important role on the final as-cast structure [8-10].
This kind of structure is barely seen in the equilibrium solidification of binary eutectic alloys.
The chemistry of each alloy is shown in Table 2.
Such ternary phase can be formed when Ni atoms take some positions of Cu in the Cu6Sn5 structure.

Ti crystallises into two main different structures, depending on the temperature, and this offer the chance to design a variety of different combination of microstructures and thus the possibility to adjust the mechanical behaviour of Ti.
In particular, at low temperatures, Ti atoms pack themselves into a hexagonal close packed structure which is known as alpha (α) Ti.
Conversely, when the temperature is increased, and a critical phase transformation temperature is crossed, Ti transforms into a body centred cubic structure, known as beta (β) Ti.
Conversely, the addition of Mn generates a much finer lamellar grain structure with ~80 μm prior β grains and significantly finer lamellae.
Park, Effect of Manganese on the Microstructure, Mechanical Properties and Corrosion Behavior of Titanium Alloys, Materials Chemistry and Physics, 180 (2016) 341-348

In the subgroup of silver there are also copper and gold with similar electronic structure.
Silver ions exhibit antibacterial properties, which are primarily associated with microbial metabolism disorder, because of chemical interaction of ions with organic structures containing "soft" nucleophilic atoms: sulfur and selenium.
Previous work [3] shows the versatility of bactericidal action of silver in aqueous solution since it is directed to a damage of the cell structure of bacteria, which contains the peptidoglycan.
Thus, abovementioned facts suggests that metal nanoparticles have biological activity which depends on their size, shape, surface structure, the state of aggregation, chemical composition, solubility, and a number of other factors [21, 22, 23].
VA Filov.: L., Chemistry, Leningrad branch, (1988) 61-80 (in Russian)

Introduction Corrosion of steel in concrete is known as one of the main cause of damage of reinforced concrete structures.
Chloride ion may penetrate into concrete from external contamination when structures are exposed to sea water and marine atmosphere or to the use of de-icing salts (NaCl, CaCl2 and MgCl2) or from internal contaminated ingredients on manufacture of the concrete mix [3].
In addition, the reduction in chloride penetration of concrete made with partial GGBS can be explained by the increase in hydration products caused by pozzolanic reactivity and the finer pore structure [44].
[17] Fly Ash for Cement Concrete—Resource for High Strength and Durability of Structures at Lower Cost; NTPC limited: New Delhi, India (2013)
Chen, Influence of GGBS on durability and corrosion behaviour of reinforced concrete, Materials Chemistry and Physics. 93 (2005) 404–411

When it comes to these fibers, particularly the coarse ones found in plant outer stems like flax, hemp, kenaf, and jute, they possess a hierarchical structure consisting of layered cell walls and bundled primary fibers.
Procedia Chemistry 19 (2016): 433-440
Composite Structures 230 (2019): 111514
"Optimization of hybrid thermoplastic composite structures using surrogate models and genetic algorithms." 
Composite Structures 80, no. 1 (2007): 21-31

Since then its use as an imaging tool has been extended to medical diagnostics as well as to nondestructive testing of materials and structures.
Cavitation has found many and varied uses in engineering, physical science (most notably in chemistry), medicine and dentistry.
The cylinder is attached to two tuned thin pipes which have structural mounting flanges at the vibration nodes so that vibrational energy is not lost to the attached structure.
The R3 mode horn produces a hexagonal structure of fluid in the centre which is not undergoing cavitation, the position of the vertices of this hexagon relate to the nodes of the mode of vibration.
It is likely that the formation of a cone shaped bubble field lies in the primary Bjerknes forces and high pressure zones can actually repel bubbles, thus it is not surprising that the predicted pressure field does not exhibit a cone like structure.

amperometric) Oxygen ZrO2:Y; Bi2O3/MoO3 H2 Sb2O5 Surface acoustic wave Humidity; NO2; H2; ethanol; O3 ZnO; InOx; LiNbO3; SiO2; WO3 Quartz balance NH3; NOx, SOx, H2S, SiO2 Capacitance H2; NH3; C2H5OH (Pd,Pt,Ir)/ SiO2 Humidity Al2O3 CO2 CuO/BaTiO3; CeO2/BaCO2/CuO; Co3O4/BaTiO3; NiO/BaTiO3 NOx CoO/In2O3; NiO/ZnO Heterostructural CO H2S ZnO/Zn2SnO4; SnO2/TiO2; SnO2/Zn2SnO4 ZnO/CuO; SnO2/CuO/SnO2 Schottky diodes H2 ZnO; TiO2 Optochemical H2, CO, alcohols WO3; Mn2O3; Co3O4; NiO; CuO Fiber optic H2, CO, alcohols WO3; Mn2O3; Co3O4; NiO; CuO Work function CH4, CO, Cl2 NiO; Fe2O3; Co3O4 Surface plasmon resonance NO2; H2S; NH3 Ta2O5; SiOxNy; TiO2 Pelistors Combustible gases and vapors Al2O3; SiO2 Pyroelectric H2; CH4 ZnO; LiTaO3; LiTiO3 Electronic nose Gases, vapors SnO2; In2O3; WO3; ZnO Membranes(filters) Al2O3; SiO2 Substrates Al2O3; SiO2; BeO; LiNbO3; ZrO2:Y Electrodes NiO/Ni; PdO/Pd; Al2O3/Pt; MgAl2O3/Pt; ITO; RuO2 Promoters PdO; RhO; Ag2O; CuO; Fe2O3; P2O5; Co3O4; NiO; MnO Structure
Sensing material Main advantages Main disadvantages Type of sensor optimal for application Metal oxides Good chemical and thermal stability; high sensitivity to a wide range of gases; long lifetime; good potential for microminiaturization; low-cost technology; wide range of operating temperatures; easily functionalized; Poor selectivity; long-term drift; poisoning Sensors for tough conditions; all types of gas sensors; electronic nose; electrodes; Carbon-based 1-D structures High surface area; RT operation; can be functionalized for chemical specificity; low thermal mass allows rapid heating with low power consumption Problems with selection, separation and electrical contacts; low selectivity; poor reproducibility; poisoning; necessity of functionalizing; long-term drift; Conductometric gas sensors; mass sensitive sensors; membranes; electrodes Standard semiconductors (Si, GaAs, etc.)
Compatibility with microelectronic technology; good potential for microminiaturization; good chemical and thermal stability; can be operated at high temperatures and in harsh environments Poor selectivity; complex technology; low sensitivity Specific applications; Schottky barriers and FET gas sensors; electronic nose Porous silicon High surface area; RT operation Poor stability and reproducibility; drift; complicated surface chemistry Specific low-temperature sensors; optical and capacitive sensors; hotplate platforms Bulk metals (films) Compatibility with microelectronic technology; good potential for microminiaturization Limited number of metals acceptable for application; poor stability of ultrathin films at high temperatures; drift; limited number of analyte can be tested H2 sensors; work function sensors; surface Plasmon resonance sensors; filters; electrodes; Metal nanoparticles High catalytic activity; good chemical selectivity for specific analytes Poor reproducibility; poor
Among other advantages of metal oxides are the simplicity of device structure, low fabrication cost, robustness in practical applications, and adaptability to a wide variety of reducing or oxidizing gases.
All these factors mean that the choice of a metal oxide for gas sensor development is determined by the type of gas sensor to be designed, the apparatus or device in which the sensor will be used, and the structure chosen for the sensor’s fabrication [3,4,37-39].