Etching of Uncompensated Convex Corners with Sides along <n10> and <100> in 25 wt% TMAH at 80 °C

This paper presents etching of convex corners with sides along and crystallographic directions in a 25 wt% tetramethylammonium hydroxide (TMAH) water solution at 80 °C. We analyzed parallelograms as the mask patterns for anisotropic wet etching of Si (100). The sides of the parallelograms were designed along and crystallographic directions (1 and crystallographic directions were smaller than 45°. All the crystallographic planes that appeared during etching in the experiment were determined. We found that the obtained types of 3D silicon shape sustain when n > 2. The convex corners were not distorted during etching. Therefore, no convex corner compensation is necessary. We fabricated three matrices of parallelograms with sides along crystallographic directions and as examples for possible applications. Additionally, the etching of matrices was simulated by the level set method. We obtained a good agreement between experiments and simulations

Etch rates of Si crystallographic planes in a 25 wt % TMAH water solution

Nagrizane su silicijumske strukture koje su na početku nagrizanja definisane kvadratnim ostrvima od termičkog silicijum dioksida. Stranice kvadrata su projektovane u različitim kristalografskim pravcima. Određene su kristalografske ravni koje se pojavljuju tokom nagrizanja ovih struktura u vodenom rastvoru TMAH koncentracije 25 tež. % na temperaturi od 80 0 C. Merenjem odgovarajućih parametara nagrizanih kristalografskih ravni sa vremenom odredili smo brzine nagrizanja uočenih kristalografskih ravni.We etched Si structures that had been defined at the beginning of etching by square islands of thermal SiO2. The sides of the squares were designed with orientations along various crystallographic directions. All the planes that appeared during etching of these Si structures in a 25 wt % TMAH water solution at a temperature of 80 deg C were determined. By measuring the time dependence of the appropriate parameters of the etched Si crystallographic planes we indirectly calculated their etch rates

Research of the operational availability and capacity utilization in the metal processing industry

U radu se pokazuje neophodnost paralelnog utvrđivanja raspoloživosti i iskorišćenosti proizvodnih u metalopreradi, jer se samo na taj način dobija pouzdana i slika ova dva fenomena.The paper deals with the necessity of concurrently determining the operational availability and capacity utilization in the metal processing industry, as only by such means can a reliable and complete overview of those phenomena be attained

Research of the operational availability and capacity utilization in the metal processing industry

U radu se pokazuje neophodnost paralelnog utvrđivanja raspoloživosti i iskorišćenosti proizvodnih u metalopreradi, jer se samo na taj način dobija pouzdana i slika ova dva fenomena.The paper deals with the necessity of concurrently determining the operational availability and capacity utilization in the metal processing industry, as only by such means can a reliable and complete overview of those phenomena be attained

Toxoplasma gondii in pork and pigs in Serbia – a real food safety hazard

Infection with the apicomplexan protozoon Toxoplasma gondii is one of the most prevalent parasitic zoonotic infections globally, with existing seroprevalences varying between continents, countries, and even within countries and between individual communities. It is estimated that one third of the world's human population is infected with T. gondii, with many studies showing that the dominant mode of infection is consumption of undercooked meat harbouring T. gondii tissue cysts. Prevalences of infection in food animals in different countries range from 0 to 93%. Because of the absence of clinical symptoms in infected animals, and the unfeasibility of rapid and unequivocal detection of microscopic tissue cysts in pork, infected pigs remain unrecognized, and their meat becomes an essential source of infection for humans. The data on T. gondii infection in pigs in Serbia from several studies, as well as on the detection of the parasite in different food categories, from fresh pork to heat-treated products, are discussed

The antimicrobial activity of triangular silver nanoplates on cotton fabric pretreated with chitozan

Triangular silver nanoplates are a type of most-studied noble-metal nanostructures over the past decade, owing to their special structural architecture, outstanding plasmonic features across both visible and IR regions, and catalytic properties for a wide range of applications. Herein, we used these nanoparticles to deposit on cotton (Co) fabric pretreated with biopolymer chitosan (CHT) and investigated their antimicrobial activity. The antimicrobial efficiency of the coated fabrics was evaluated toward Gram-negative bacteria E. coli, Gram-positive bacteria S. aureus and fungus C. albicans. It was found that deposited silver nanoparticles imparted excellent antimicrobial properties to Co fabric

Reinforcement of the pressure sensor diaphragm by etching in 25%tmah water solution

Primenom maskless tehnike, koja se bazira na vlažnom hemijskom nagrizanju u vodenom rastvoru TMAH koncentracije 25 tež. %. na temperaturi od 80 0 C, na Si pločice uspešno su napravljene dijafragme sa ojačanjem. Ojačanje je projektovano za ravne kvadratne dijafragme debljine 30 μm i površine 2040 μm x 2040 μm, čiji je nominalni opseg rada 1 bar. Vrednost pritiska na kojoj neojačana dijafragma puca je 12 bar. Eksperimentalno je pokazano da je ojačanje povećalo pritisak na kojem puca dijafragma 1.8 puta za dijafragmu sa ojačanjem širine 90 μm, odnosno 2.5 puta za dijafragmu sa ojačanjem širine 40 μm. Ovo poboljšanje pokazuje da je u okviru samog senzora moguće MEMS tehnologijama povećati vrednost pritiska na kojem dolazi do pucanja dijafragme i njenog nepopravljivog oštećenja.Reinforcements of a pressure sensor diaphragm have been designed and fabricated on the Si wafers by maskless wet etching technique. Maskless wet etching technique has been performed in the 25% TMAH water solution at the temperature of 800. Reinforcements are designed for the 30 μm thick and flat square diaphragm. Area of the diaphragm is 2040 μm x 2040 μm. Operation pressure range of the flat diagrapham is 1 bar. Measured burst pressure of the flat diaphragm is 12 bar. For the samples of the diaphragm with the 90 μm wide reinforcement measured burst pressures are 1.8 times higher than for the flat one. For the samples of the diaphragm with the 40 μm wide reinforcement measured burst pressures are 2.5 times higher than for the flat one. Higher measured burst pressures of the diaphragms with reinforcements show that the improvement is possible on the sensor level by using maskless wet etching technique

SOI piezoresistive low pressure sensor for high temperature environments

Silicon-On-Insulator (SOI) wafers utilizing a novel maskless wet etching technique. The prototype has a structured square diaphragm with a concentric boss. The SOI pressure sensors have piezoresistors dielectrically isolated from each other and from the substrate by silicon dioxide. A high temperature transducer prototype has been made utilizing the fabricated sensor. A high temperature method for pressure measurements has been formed. The transducer prototype performance was measured at temperatures up to 300 0С. These SOI pressure sensors are intended for extreme environmental conditions and high operating temperatures that are often needed in military-grade applications and where it is necessary to perform sensitive low pressure measurements. Some examples include aerospace applications like aircraft engines, wind tunnels, various missiles, etc

Antibacterial activity of copper nanoparticles

Copper nanoparticles (CuNPs), with an average particle size of about 5 nm, was prepared by the simple chemical reduction procedure. TEM and UV– Vis spectroscopy contributed to the analysis of size and optical properties of CuNPs, and their antibacterial activity was evaluated toward human pathogenic bacteria Escherichia coli and Staphylococcus aureus, in a concentration dependent manner. The changes in the cell membrane morphology of tested strains were investigated by atomic force microscope (AFM), after 2 h of their contact with CuNPs. It was found that CuNPs cause different types of cell membrane disruptions, as well as that S. aureus bacteria were slightly resistant to the cell membrane damage than E. coli

Towards understanding intermolecular interactions in hydantoin derivatives: the case of cycloalkane-5-spirohydantoins tethered with a halogenated benzyl moiety

A series of cycloalkane-5-spirohydantoins bearing a halogeno substituted benzyl group (X = Cl and Br) in position 3 has been synthesized and their structures (1-6) have been determined by a single crystal X-ray diffraction method. These compounds have multiple functional groups, which allow greater competition and/ or cooperation among the different intermolecular interactions in the formation of their crystal structures. The molecules are linked together by paired N-H... O hydrogen bonds in R22(8) rings, while the CH. O interactions lead to their further association into double chains. The contribution of the cycloalkyl ring depends on its conformational flexibility and the multiple C-H donor implications. In the case of compounds 1-4 bearing the cyclopentyl or the cyclohexyl ring, halogen bonding (X...O) interactions give rise to a supramolecular pseudo-hexagonal network. In addition, the C-H... X interactions with a higher degree of multifurcation at the halogen acceptor have an important role in the formation of the crystal structure. Regarding compounds 5 and 6 with the cycloheptane ring, the X. O interaction is absent, and along with the C-H. X interactions, these compounds realize an alternative crystal structure with an emphasis on the X. p interactions. The lattice energies of all these crystal structures, as well as the intermolecular pair energies, have been calculated using PIXEL and further partitioned into coulombic, dispersive, polarization and repulsive factors. The crystal structures have also been subjected to Hirshfeld surface analysis which reveals that approximately 75% of the close contacts correspond to relatively weak interactions. The application of both concepts has provided a new insight into the relationship between the molecular interactions and crystal structures of the hydantoin derivatives.This is the peer-reviewed version of the following article: Crystengcomm, 2017, 19, 3, 469-483 [https://dx.doi.org/10.1039/C6CE02210C][http://cer.ihtm.bg.ac.rs/handle/123456789/2204