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Aluminum oxynitride (AlON) exhibits excellent mechanical properties and good optical transparency in the ultraviolet to near-infrared range and can be used in military and civilian fields. However, the troublesome molding of AlON, especially for complex shapes, limits its promotion and application. Therefore, transparent AlON ceramics with complex morphologies were prepared for the first time by a novel spontaneous coagulation casting (SCC) and pressureless sintering method. In this study, we report a simple carbothermal reduction and nitridation (CRN) method for synthesizing high-purity AlON powder, which is especially suitable for wet casting without anti-hydration treatment. The dispersion and gelation behavior of AlON slurries by isobutene maleic anhydride copolymer (Isobam104) and tetramethylammonium hydroxide (TMAH) were extensively investigated. With the addition of 0.9 wt% Isobam104 and 15 mL/L TMAH, the AlON slurries can achieve a solids loading of up to 45 vol% with the lowest viscosity (460.4 mPa·s-10 r/min) and the AlON green body is free of cracks and deformation during drying and demolding processes. Finally, the AlON green bodies with square and polygonal irregular morphologies were fabricated via a simple SCC method. High transparent AlON ceramics of a maximum transmittance up to 77.3% at 2000 nm and 72.2% at 632 nm were obtained by pressureless sintered at 2000 °C for 6 h. The SCC method has great potential in preparing ceramics with controllable shapes. [ABSTRACT FROM AUTHOR]

The paper presents research on elaboration of well dispersed and stable aqueous suspensions of ZnO fine powder. Within the work the influence of the type and concentration (0.2 wt% - 1.2 wt%) of selected dispersing agents (i.a. poly(acrylic acid)-based polyelectrolyte and tetramethylammonium hydroxide), solid loading (30 - 50 vol%) and milling time (1–3 h) on the rheological properties of the slurries was investigated. Two-step sintering (970/920 °C, 2 h) was applied to sinter the green bodies obtained by slip casting. The lowest viscosity of ZnO suspensions was obtained for the addition of 0.4 wt% of poly(acrylic acid)-based polyelectrolyte (PAA) and TMAH. ZnO suspension containing PAA had negative zeta potential in the whole pH range. The highest solid loading obtained in the study was 50 vol%. The applied two-step sintering allowed to obtain samples of high density (above 96% of TD) and homogeneous microstructure of average grain size of 640 nm. ZnO sintered bodies were characterized by different electric properties at the core part and outer part of the sample which was caused by the differences in concentration of oxygen vacancies. [ABSTRACT FROM AUTHOR]

The study aimed at evaluation of the rheological properties of aqueous suspensions of SiC stabilized with either TMAH (tetramethyloammonium hydroxide) or NaOH in the amount of a given dispersant in the range of 0–1.0 wt% as calculated on the dry mass of SiC powder. The optimal amount of the dispersants was finally evaluated at 0.4–0.6 wt %, based on the results of rheological studies (flow curves and viscosity curves) and the sedimentation rate, which corresponded to the pH of the suspension within the range of 9.5–10.5. The amount of the dispersant here did not depend on the solid volume fraction in the suspension, but rather, according to the zeta potential measurement results, the pH range guaranteed the formation of a stable suspension. This effect allowed to propose a dispersant mechanism for stabilizing the suspension. The maximum amount of silicate anions formed, accordingly, in the pH range of 9.5–10.5 on the surface of SiC particles, which in turn could be able to adsorb Na+ or TMA+ cations and thus increase the thickness of the Stern layer, increasing electrostatic repulsion between the SiC particles and improving the stabilization of suspensions and their rheological properties. However, the increase in suspension pH deteriorated their stabilization – most likely due to the occurrence of polymerization of amorphous silica and the presence of additional cations in water increasing its ionic strength. These suggestions were confirmed by the results of XPS analysis of the chemical state of SiC particle surfaces. [ABSTRACT FROM AUTHOR]

• An extraction method is developed for impurities in different edible oils using GFAAS. • It is simple and sensitive and does not use microwave or hot plate for digestion. • It is an alternative method to determine ultratrace impurities in various edible oils. • Applicable to different edible oils extracted from various seeds. • TMAH and EDTA together resulted in better detection limits for edible oils. A new method for extraction and determination of trace and ultratrace impurities from edible oils via an ultrasound-assisted extraction using tetramethylammonium hydroxide (TMAH) and ethylenediaminetetraacetic acid (EDTA) has been described. Method is simple and sensitive. Extraction variables like pH, concentrations of TMAH and EDTA, ultrasonication and centrifugation times were all optimised for analytes using engine-oil. Under optimised conditions, extraction of spiked analytes from all the edible oils into aqueous-medium were investigated and found to be quantitative (89–101%). Using this method, concentrations of impurities in edible-oils were determined by graphite furnace atomic absorption spectrometer (GFAAS) using standard-addition calibration method and validated with microwave-digestion method. The method was successfully applied to edible oils extracted from various seeds such as mustard oil, sun flower oil, sesame oil, ground nut oil, coconut oil, rice bran oil and corn oil containing ultratrace impurities. Accuracy of developed method for edible-oils was checked with corresponding results obtained by microwave digestion method. [ABSTRACT FROM AUTHOR]

Tetramethyl ammonium hydroxide (TMAH) is a corrosive and toxic chemical with a stable structure. Therefore, it is important to check whether surface water or wastewater contains TMAH. In addition to using ultrasound and ozone procedures to degrade TMAH in wastewater, in this study, the effects of TMAH degradation were explored by combining the two procedures while varying the reaction conditions. According to the experimental results, the degradation efficiency of TMAH by the single ultrasonic process was un-satisfactory, and the highest degradation ratio was only 8.4% after for 60 min, while the highest total organic carbon (TOC) mineralization ratio was only 7.1%. Ozonation is more effective for the degradation of TMAH, where the highest TMAH removal rate and mineralization rate can reach 58.4% and 21.8%, respectively. As the ultrasound is combined with the ozone procedure (named as sonozone) at the optimal condition, the TMAH removal ratio reaches 89.5% following by mineralization ratio of 77.5%. The toxicity test performed using the cell survival rate showed that ozonation and sonozone have better effects for improving the cell viability and reducing the toxicity of the water sample, and the sonozone process proves that the combination of two procedures indeed has synergistic oxidation efficiency. [ABSTRACT FROM AUTHOR]

Highlights • Doehlert design and desirability function allow optimize fish samples dissolution. • Ultrasound energy was used to increase the efficiency of the TMAH dissolution. • The method presents good analytical characteristics allowing simultaneous treatment. • Calcium, Mg, Fe and Zn were determinate from fillet fish samples using FAAS. Abstract Doehlert design and desirability function were used in the optimization of an ultrasound assisted dissolution method of fish fillet samples with tetramethyl ammonium hydroxide (TMAH) for the determination of Ca, Fe, Zn and Mg by flame atomic absorption spectrometry. The variables values after optimization were 620 μL (volume of TMAH), 25 min (sonication time) and 46 °C (bath temperature). The quantification limits for Ca, Mg, Fe and Zn were 56, 107, 23 and 2.9 μg g−1, respectively. Accuracy was evaluated by comparing the results generated from the analysis of the samples treated by the proposed method and by wet digestion. Additionally, accuracy for Fe and Zn was assessed by the analysis of certified reference materials Tort-3 (Lobster hepatopancreas), ERM-CE 278 (mussel tissue) and Dolt-4 (Fish liver). There were no significant differences between the results obtained at a 95% confidence level when results were evaluated by t -test application. [ABSTRACT FROM AUTHOR]

In this study, titanate nanotube arrays (TNAs) were prepared by using electrochemical anodization, and the silver nanoparticles were deposited on a titanate dioxide nanotube array (Ag/TNAs) by green synthesis methods. The Ag/TNAs was further applied to degrade tetramethylammonium hydroxide (TMAH) in a photoelectrochemical (PEC) system. SEM results showed that the diameter and length were 121.7 nm and about 3.45 µm, respectively, for TNAs. The deposited silver nanoparticles showed spherical and flaky shapes depending on using tea and coffee as green reducing agents, respectively. XPS showed that the atomic percentage of silver in Ag/TNAs-CTC5 and Ag/TNAs-CGA2.5 was 6.60% and 1.76%, individually. Results of UV–vis analyses indicated that the absorbance edge of TNAs red-shifts to a more extended wavelength region after silver modification. The photocurrents of Ag/TNAs-CTC5 (5.03 mA/cm2) and Ag/TNAs-CGA2.5 (3.63 mA/cm2) were 51% and 32% higher than that of TNAs (2.45 mA/cm2), illustrating that the photocatalytic ability of TNAs was significantly enhanced after silver nanoparticles modifying. Electrochemical impedance analysis (EIS) results confirmed that the electron lifetime of Ag/TNA-CTC and Ag/TNAs-CGA was 6.6 and 1.82 times longer than that of the TNA in the PEC system. Mott-Schottky analyses indicated that TNAs, Ag/TNAs-CTC5, and Ag/TNAs-CGA2.5 are n-type semiconductors with a density of dopants of 3.16 × 1019, 1.42 × 1020, and 9.49 × 1019 cm−3. The results of TMAH degradation showed that Ag/TNAs-CTC5 performed the highest efficiency at pH= 3 in the PEC system. EPR analyses of TNAs and Ag/TNAs-CTC5 showed a peak intensity of 1:2:2:1 which represented the characteristic DMPO−OH, revealing the dominant oxidants of the PEC system. [Display omitted] [ABSTRACT FROM AUTHOR]

Highlights • Because of the different mechanisms involved, comparisons of data from thermochemolysis and chemical methods must be done carefully. • Thermochemolysis should be viewed and used as a complementary method for the analysis of soil and sediment organic matter. • Thermochemolysis is a rapid and powerful tool suitable for routine analyses of soil organic compounds such as lignin, carbohydrates and lipids. Abstract Published data from different techniques used in the analysis of the main biomolecular families (lignin, carbohydrates and lipids) in 100 cm depth peat cores from the Sagnes peat bog (Limousin, France) were compared. Thermochemolysis using tetramethylammonium hydroxide was compared with the classical chemical degradation methods for lignin (CuO-NaOH oxidation) and carbohydrates (acid hydrolysis with HCl), and the Bligh and Dyer extraction method for lipids. Differences observed between the methods are mostly due to the different degradation mechanisms involved in each method. For lignin, the selective cleavage of β O 4 aryl ether bonds during thermochemolysis allowed identification of a more oxidized/degraded lignin pool in the deepest part of the peat core. For carbohydrates, the capacity of thermochemolysis to detect free (or terminal) carbohydrates showed an increase in microbial contribution at the interfaces between three distinct peat layers: the acrotelm, the upper part of the peat permanently above the water table; the mesotelm, the layer where water table fluctuations occur; and the catotelm, the bottom layer of peat that is permanently below the water table. For the lipid fraction, thermochemolysis revealed a lipid pool that was more influenced by microbial reworking. These results imply that, depending on the techniques used, the interpretation of the extent of degradation or source could differ. Therefore, TMAH thermochemolysis could be viewed and used as a complementary method of analysis, offering additional molecular data and contributing to a better understanding of the nature and sedimentation processes of organic matter in peat bogs. [ABSTRACT FROM AUTHOR]

Six cambic stagnohumic gley soil profiles located on marginal peatland between a gymnosperm plantation (Sitka spruce (Picea sitchensis (Bong.) Carr.)) and heather grassland in Wark Forest (northeast England), were analysed using 13C labelled tetramethylammonium hydroxide (TMAH) thermochemolysis to yield methylated phenolic and oxygenated aromatic products. The identification of aromatic compounds derived from the thermally assisted hydrolysis and methylation (THM) of vascular plant, Sphagnum and non- Sphagnum spp. allowed changes in vegetation both within the top 50 cm of peat (surficial peat) and across the site to be explored. Four sphagnum acid pyrolysis products reflected the presence of Sphagnum spp.; lignin phenols reflected the presence of vascular inputs; whilst 3,4-dimethoxybenzenepropanoic acid methyl ester reflected the presence of the non- Sphagnum moss Polytrichum commune. 210Pb dating of the surficial peat suggests that a historic change in vegetation identified by the changes in aromatic compound distribution with depth, coincide with the adjacent plantation of coniferous woodland. The peat closest to the plantation has seen a shift from grass dominated vegetation, to a species diverse vegetation cover, including Sphagnum spp. and vascular vegetation. These results suggest that Sphagnum spp. are able to survive not only perturbing environmental conditions, but are also able to establish themselves amongst non- Sphagnum species. This study demonstrates the ability of 13C-TMAH THM to be utilised as a screening method for the rapid characterisation of aromatic biomacromolecules in peat to identify key historic and current vegetation inputs. This technique in combination with peat dating helps identify the degradation patterns of these inputs and associated carbon dynamics, providing information on the resilience of current peat deposits to climate change and changing peat conditions. • Biomacromolecules were characterised by 13C-TMAH thermochemolysis in surficial peat. • Distinct aromatic compounds from Sphagnum spp. , non- Sphagnum mosses and vascular plants were identified. • Surficial peat was dated using 210Pb. • 13C-TMAH thermochemolysis can be used as a rapid screening method to identify vegetation inputs in peat. [ABSTRACT FROM AUTHOR]

The control of environmental pollution has demanded increasingly determination of sulphur in a variety of matrices. Different analytical methods have been developed for the determination of this analyte in biodiesel fuel using various analytical techniques, including spectroanalytic and chromatographic methods. In this work a square-wave cathodic adsorptive stripping voltammetric (SW-AdCSV) procedure is proposed for the determination of sulphur in biodiesel, using a glassy carbon electrode modified with mercury-film (MFE). A buffer solution containing sodium acetate 1.4 mol L −1 and acetic acid 2% was used as supporting electrolyte in two different media (methanol an propanol). The voltammetric measurements were performed adding 70 μL of biodiesel sample previously treated with tetramethylammonium hydroxide (TMAH) to the supporting electrolyte. The method showed good linearity (r = 0.998) in the determination of sulphur in biodiesel (medium-concentration of 2.68 × 10 −8 mol L −1 (1.07 × 10 −3 mg kg −1 ) for a confidential level of 95%. Low values of limit of detection-LOD (3.29 × 10 −10 mol L −1 (1.32 × 10 −5 mg kg −1 ) and limit of quantification-LOQ (1.10 × 10 −9 mol L −1 (4.40 × 10 −5 mg kg −1 ) indicate a good sensitivity of the method. A validation of the procedure was carried out by comparing this procedure with the results obtained by an official method, using the same sample, through Teste- t of Student (confidence level of 95%). These results indicated that both methods are statistically equivalent, thus demonstrating the feasibility of the new method. [ABSTRACT FROM AUTHOR]

One of the main objectives of present and future space exploration missions dedicated to astrobiology is the detection of organic molecules of interest for life (e.g. amino and fatty acids). With this aim, a sample preparation and a gas chromatograph (connected to a mass spectrometer) are generally used. To date, tetramethylammonium hydroxide (TMAH) has been the first and only thermochemolysis reagent to be used for in situ sample preparation and chemical analysis of planetary environments. Although TMAH is widely used in terrestrial laboratories, numerous applications also leverage other thermochemolysis reagents that may be more relevant than TMAH to meet both scientific and technical objectives of space instrumentation. The present study compares the performance of tetramethylammonium hydroxide (TMAH), trimethylsulfonium hydroxide (TMSH), and trimethylphenylammonium hydroxide (TMPAH) reagents on molecules of interest to astrobiology. The study focuses on the analyses of 13 carboxylic acids (C 7 –C 30), 17 proteinic amino acids, and the 5 nucleobases. Here we report the derivatization yield without stirring or adding solvents, the detection sensitivity with mass spectrometry, and the nature of the degradation products from the reagents produced during pyrolysis. We conclude that TMSH and TMAH are the best reagents for analyzing carboxylic acids and nucleobases. Amino acids are not relevant targets for a thermochemolysis over 300 °C as they are degraded and showed high limits of detection. As TMAH, and probably TMSH, meet the space instrumentation requirements, this study informs sample treatment approaches prior to GC-MS analysis in in situ space studies. The thermochemolysis reaction using TMAH or TMSH is also recommended for space return missions to extract organics from a macromolecular matrix, derivatize polar or refractory organic targets, and volatilize with the fewest organic degradations. [Display omitted] • The fast one-pot thermochemolysis reaction break the matrix, desorb, derivatize, and volatilize organic compounds. • Pyr-GC-MS efficiently analyzesbulk samples with organic molecules present in a wide concentration range (pmol-mmol). • TMAH and TMSH thermochemolysis reagents enable the derivatization of polyfunctional and long-chain organic molecules. • TMAH and TMSH are suited for (bio-geo)chemistry laboratory work, spaceflight missions, and return sample analysis. [ABSTRACT FROM AUTHOR]

In this work, we consider eight silicon wet etching conditions using 20 % or 25 % Tetramethyl Ammonium Hydroxide (TMAH), each at 60 °C , 70 °C , 80 °C or 90 °C in order to study the TMAH kinetics and planar dependence on formation of upright pyramids by anisotropic etching on a (100) Si substrate. With the aid of negative square mask patterning, we are able to fabricate upright micro-pyramids having well defined facets with a smooth morphology. A new methodology termed as the 'Variable Time Index Method' is employed to understand the etch rate variation as a function of time and identify the etch rates along the (111) family of planes and consequently the planar dependence due to TMAH etch conditions. For each of the etching conditions, analysis using Scanning Electron Microscopy (SEM) is conducted to investigate the etched pyramid morphology and suitably identify the conditions under which deviation from the desired plane direction and surface are obtained. Ideal micro-pyramid morphology, vertex alignment and orientation are obtained for etch conditions of 20% and 25% TMAH, at 80 °C. [ABSTRACT FROM AUTHOR]

The study aimed at evaluating the stabilisation and rheological properties of aqueous suspensions (30 vol%) of pristine (non-oxidised) and oxidised fine SiC powders which were stabilised either with NaOH or TMAH (tetramethylammonium hydroxide). The extensive oxidation of the SiC powder surface was confirmed by the results of XPS and FT-IR analyses. The optimal amount of a given dispersant depended, according to the results of zeta potential measurements, on a pH range guaranteeing formation of a stable suspension. This effect allowed the authors to propose a mechanism of stabilisation of the SiC suspensions. Herein, the maximum amount of silanol groups is formed on the SiC particles surface in the pH range of 9.5–11 which then adsorb Na+ or TMA+ cations, thus creating a favourable system of electrostatic interactions. In turn, it increases the electrostatic repulsion between SiC particles and improves the stabilisation of the suspensions and their rheological characteristics. An increase in the surface oxidation of the SiC particles leads to reducing the repulsive forces between the powder particles. Apparent viscosity of the suspensions made of SiC UF10 powder, regardless of the type and amount of the fluidizer, is very low (5–10 mPa s) and shows a slight increase as the shear rate increases. The oxidation of the SiC powder changes the rheological characteristics of the suspensions, which may be caused by their rapid sedimentation. Stability of the prepared SiC suspensions was also assessed by casting them into a plaster mould and then by sintering and characterisation of the resulting samples. [Display omitted] • Well-stabilised fine SiC suspensions can be produced using NaOH or TMAH additives. • pH of the stable SiC suspensions was 9.5–11 with the lowest apparent viscosity. • In the pH 9.5–11 a pattern of the interactions between the SiC particles exists. • Suspensions of the oxidised SiC powder were difficult to stabilise. • Dense polycrystals were sintered from selected suspensions using SiC UF10 powder. [ABSTRACT FROM AUTHOR]

Biotoxicity tests are considered methods to assess toxicity of substances or complex mixtures of industrial wastewater effluents. In this study, Daphnia similis and Cyprinus carpio were used to examine the acute toxicity of thin-film transistor liquid crystal display (TFT-LCD) wastewater effluents in Taiwan. Among examined effluents, 67% were found to be toxic to D. similis and 27% were toxic to C. carpio. The biotoxicity of TFT-LCD wastewater effluents might be due to the presence of tetra-methyl ammonium hydroxide (TMAH), since 48-h lethal concentration 50 (LC50) of TMAH to D. similis was found only 0.75 mg/L. The acute toxicity of NH4+-N to D. similis varied with 48-h LC50 values of 18.5 mg/L at pH 7.0 and 155 mg/L at pH 6.5. The obtained results of this study indicated that NO3--N, SO42-, Cl- and heavy metals were not the major concerns in TFT-LCD wastewater effluents regarding acute toxicity. [ABSTRACT FROM AUTHOR]

The pre-passivation surface treatment process with tetramethylammonium hydroxide (TMAH)-based wet solution was proposed for the minimization of the leakage current ( I leak ) in AlGaN/GaN metal-insulator-semiconductor high electron mobility transistors (MIS-HEMTs). This process step contributes to the simultaneous decrease of the surface current ( I surf ) in the active region of device and mesa-isolated region by removing the surface states and traps related to nitrogen (N) vacancy, Ga-oxide, and dangling bonds. Using the surface treatment, the fabricated device achieves a lower off-state current ( I off ) of ∼10 −12 A/mm, a higher on/off current ratio ( I on / I off ) of ∼10 11 , a small subthreshold swing ( SS ) of 68.4 mV/dec. The reduced I leak also improves breakdown voltage (BV). In addition, the interface trap density ( D it ) between the SiN layer and the AlGaN surface was extracted to evaluate the quality of the SiN/GaN interface, which showed that the treatment decreases the D it with reduction of the surface defects. [ABSTRACT FROM AUTHOR]

Semiconductor wastewater usually has a low level of dissolved oxygen and alcohol because ultra-pure water used in the process undergoes rigorous degassing and wafer development, respectively. In this study, we investigated the degradation mechanism of tetramethylammonium hydroxide (TMAH), a compound of concern in the semiconductor manufacturing process, during the UV-LED/H 2 O 2 under initial nitrogen purging conditions to remove dissolved oxygen. The effect of the initial degassing was negligible due to the in-situ O 2 production during the reaction. Along with hydroxyl radical (•OH), we first observed hydrated electron (e aq •-) formation by electron paramagnetic resonance (EPR) analysis in the presence of an excessive amount of tertiary butanol (t-BuOH), •OH scavenger, during the UV-LED/H 2 O 2 reaction. However, the contribution of e aq •- on TMAH degradation was negligible compared to •OH which played a major role in TMAH degradation. The calculated reaction rate constant of TMAH with •OH was 7.5 × 107 M−1 s−1. From competitive kinetics, [•OH] ss and k •OH, TMAH value was found to be 7.1 × 10−13 M and 7.5 × 107 M−1 s−1, respectively. The optimum pH and temperature for TMAH degradation were pH 7 and 35 °C. Three demethylated amines (trimethylamine, dimethylamine, and methylamine), along with NH 4 + and NO 3 - ions, were detected as the byproducts, implying that the main degradation mechanism of TMAH in this reaction is H abstraction by •OH-induced oxidation and hydrolysis resulting from the •OH-induced oxidation, and demethylation. Our result implies that the UV-LED/H 2 O 2 reaction can be one of the options to treat TMAH contaminated water by recycling H 2 O 2 produced in the semiconductor manufacturing process and lowering the energy consumption by using UV-LED. [Display omitted] • OH radical played a major role in the TMAH degradation in the UV-LED/H 2 O 2 reaction. • Hydrated electron (e aq •-) was observed, but the contribution can be neglected. • Neutral pH and higher temperature favored TMAH degradation. • Demethylated amines, ammonium, and nitrate were identified as major byproducts. • H abstraction by •OH oxidation and hydrolysis were the main degradation reactions. [ABSTRACT FROM AUTHOR]

A new Surfactant-based Removal Probability Function (S-RPF) is proposed to perform Kinetic Monte Carlo simulations of anisotropic etching of silicon in alkaline solutions containing additives, such as tetramethyl ammonium hydroxide (TMAH) or potassium hydroxide (KOH) with small amounts of surfactants (e.g., Triton) and/or alcohols (e.g., Isopropanol = IPA). The S-RPF is built as the product of (i) a modified removal probability function (M-RPF), for pure etchants, and (ii) an additive inhibition term (I-RPF), which describes the orientation-dependent reduction in certain etch rates due to the selective adsorption of the additive on particular silicon surfaces. By construction these functions depend only on a few parameters, whose values are determined by an evolutionary algorithm (EA), which minimizes the differences between the experimental and simulated etch rates for a small set of silicon surfaces. In this respect, the paper introduces a transformation matrix to constrain the evolutionary search space, thus accelerating the convergence for both the M-RPF and I-RPF parameters. The simulated etch rates for numerous silicon orientations in TMAH + trion at different temperatures as well as KOH + IPA show good agreement with the experimental data. Compared to previous studies, the new S-RPF model describes the anisotropy at local etch rate maxima and minima around Si(1 0 0) and Si(1 1 0) with much better accuracy. The simulation of three-dimensional microstructures confirms the validity of the new S-RPF model for MEMS fabrication in alkaline etchants containing additives. [ABSTRACT FROM AUTHOR]

One piece from Mumujyana ruins and one piece from Urasoe Yōdore (a mausoleum), both belong to Ryukyu Kingdom, were analyzed by direct and derivative pyrolysis gas chromatograph/mass spectrometry (Py-GC/MS). Direct Py-GC/MS chromatogram at m / z = 108 of both samples showed that peaks of 3-pentadecylphenol and 3-heptadecylphenol were relatively weak, and the shape of peaks from low molecular weight component group formed a platform, different from the mountain type of the three standard Toxicodendron vernicifluum, Toxicodendron succedanea , and Gluta usitata lacquers. However, analysis of a mixture of the three kind lacquers and a sample of T. succedanea mixed with T. vernicifluum showed a similar platform shape on chromatogram at m / z = 108. In addition, in order to confirm this result, derivative Py-GC/MS was also performed, and the results are compared and discussed. [ABSTRACT FROM AUTHOR]

An immobilized-cell process followed by activated carbon adsorption was developed to treat the tetra-methyl ammonium hydroxide (TMAH) containing low-strength electronic wastewater. The isolated TMAH-degrading bacterium (Mycobacteriumsp. TMAH-W0418) and activated sludge were entrapped in polyethylene glycol cubes. The packing rate of 60% (v/v), biomass ratio betweenMycobacteriumand activated sludge of 2:3 (w/w), and total biomass of 7,000 mg/L were found to be optimal for removing dissolved organic carbon (DOC) and TMAH with the concentrations around 1 and 0.2 mg/L, respectively. Granular activated carbon was used to further decrease the DOC and TMAH in the effluent, and the concentrations of DOC and TMAH in the effluent of the combined system were below 1 mg/L and almost 0 mg/L, respectively. Scanning electron microscope results confirmed that cells were effectively immobilized in the polymer matrix. Thick biofilm on the surface of both polymer carriers and activated carbon granules was observed. The microorganism concentration estimated by protein assay increased and the immobilized-cell activity maintained constant during the operation period. From these observations, it was concluded that immobilized-cell process combined with activated carbon system could successfully treat low-strength electric wastewater to yield effluent with DOC level below 1 mg/L. [ABSTRACT FROM PUBLISHER]

Tetramethylammonium hydroxide (TMAH) is an alkaline, neuronal toxic, and chemically stable compound; furthermore, it is widely used in the high-tech industry as a developing agent. Disposal of TMAH wastewater from an industrial plant is a difficult and costly problem. Ultraviolet light (UV) activated persulfate (S2O82-) is an advanced oxidation process proven to be effective in destroying a variety of organic pollutants. This bench-scale study investigated the feasibility of using the UV/S2O82- process to treat TMAH. The effects of various operational parameters, including pH conditions, dosages of persulfate, UV intensities, and system temperatures were evaluated. The results revealed that pH 2 exhibited higher decay rate of TMAH (kobs = 0.0331 ± 0.0031 min-1) than other pH conditions (pH 7 and 11) at 20 °C. In general, the TMAH decay increased with increasing persulfate dosage; however, the highest TMAH degradation rate was observed with a persulfate concentration of 50 mM. Also, higher reaction temperature and stronger UV irradiation can increase the degradation of TMAH. TMAH degradation byproducts were identified and finally transformed to nitrate and ammonium, which suggested that the demethylation mechanism was the main degradation pathway. [ABSTRACT FROM AUTHOR]

This paper reports a fabrication process of a capacitive microelectromechanical system (MEMS) accelerometer with a highly symmetrical spring-mass structure for the high device performance, which is composed of eight springs and a central mass. The sandwich accelerometer is constituted by top layer, middle layer and bottom layer. The suspended spring-mass structure in the middle silicon layer is formed simply by double thermally grown oxide layers and the mask-maskless wet anisotropic etching, avoiding the generally adopted deep-groove photolithography when fabricating the thin spring. Moreover, the gap between electrodes can be determined by the thickness of the oxide layer in this process. The surfactant-modified TMAH is selected as the etchant because it not only provides the minimum undercutting at the mass corner, thus saving much space of the compensation parts, but also allows the good control of spring thickness at the low etch rate. The spring shape evolution during etching in surfactant-modified TMAH is simulated and the obtained rhombic cross-section has the advantage of easily identifying the thickness of the spring from its width according to their crystal orientation relation. The three silicon layers are bonded through silicon fusion bonding (SFB) at temperature >1000 °C to relax surface stresses that could be present in the material prior bonding. Preliminary test result shows the sensitivity of 60 mV/g with good linearity of R² = 0.99979 in a closed-loop interface circuit. The advanced accelerometer performance could be expected due to the symmetrical structure, the large proof mass, controllable spring shape, the narrow uniform capacitive gap, and the IC-compatible process. [ABSTRACT FROM AUTHOR]

Abstract: A thin, flat and single crystal membrane on which to mount sensors is generally required for integration with electronics through standard silicon processing technology. We present an approach to producing single crystal membranes of germanium with in-built tensile strain, which serves to keep the membrane flat and ripple free, and demonstrate a 600nm thick, free-standing 1mm2 Ge membrane. We convert the fabrication technique into an integrated-circuit compatible wafer scale process to produce 60nm thin membranes with large areas of 3.5mm2. The single crystal Ge membrane provides an excellent platform for further epitaxial growth or deposition of materials. [Copyright &y& Elsevier]

Highlights: [•] An original two-step thermochemolysis method based on reactivity differences is proposed. [•] Two chemical agents HMDS (silylation) and TMAH (transmethylation) were selected. [•] Additional information on complex natural organic matters were provided. [•] Mostly sugars and monomers from biopolymers such as lignin, cutins and suberins were identified in the first and second step respectively. [Copyright &y& Elsevier]

Abstract: In the present work, the dispersion of boron carbide powder in aqueous media was studied in terms of surface treatment, surface characterization, the particle stability as well as rheological behavior, etc. Initially, the influence of the impurity and boron oxide from commercial B4C powder on the slurry dispersion was studied. The surface compositions, bonding and surface charge behavior of acid-treated B4C powder were investigated systematically. The positive effect of TMAH (tetramethylammonium hydroxide) on the dispersion of as-treated B4C powder was studied and the content was optimized based on rheological measurement. Results showed that well dispersed B4C slurries could be developed with the solid loading of 55vol.% using 0.18wt% TMAH as the dispersant. The dispersion mechanism was also investigated before and after TMAH addition. [Copyright &y& Elsevier]

Highlights: [•] Ceria nanoparticles were synthesized by a simple, easy to scale-up method. [•] The effect of EG and TMAH on particle and crystallite size was studied. [•] Complete elimination of nitrates and organic matter could be achieved at 500°C. [•] The activity of ceria nanoparticles in COPrOx depends on calcination temperature. [•] Samples pretreated at 500°C presented high conversions at the lowest temperature. [ABSTRACT FROM AUTHOR]

A simple method was developed for determining the total lead content in lipstick samples by graphite furnace atomic absorption spectrometry (GFAAS) after treatment with tetramethylammonium hydroxide (TMAH). Multivariate optimization was used to establish the optimal conditions of sample preparation. The graphite furnace heating program was optimized through pyrolysis and atomization curves. An aliquot containing approximately 50mg of the sample was mixed with TMAH and heated in a water bath at 60°C for 60min. Using Nb as the permanent modifier and Pd as the chemical modifier, the optimal temperatures were 900°C and 1800°C for pyrolysis and atomization, respectively. Under optimum conditions, the working range was from 1.73 to 50.0μgL−1, with detection and quantification limits of 0.20 and 0.34μgg−1, respectively. The precision was evaluated under conditions of repeatability and intermediate precision and showed standard deviations of 2.37%–4.61% and 4.93%–9.75%, respectively. The % recovery ranged from 96.2% to 109%, and no significant differences were found between the results obtained using the proposed method and the microwave decomposition method for real samples. Lead was detected in 21 tested lipstick samples; the lead content in these samples ranged from 0.27 to 4.54μgg−1. [ABSTRACT FROM AUTHOR]

Abstract: The cleaning of copper surface after chemical mechanical planarization (CMP) process is a critical step since the surface would be contaminated by a large number of slurry particles such as silica or alumina and organic residues such as benzo triazole (BTA). The presence of organic residues results in a hydrophobic surface, which leads to problems in particle removal and drying. A major function of a post copper CMP cleaning solution is to remove these organic contaminants without significant increase in the surface roughness. Alkaline or acidic cleaning solutions are usually preferred over neutral solutions since they can remove organic residues better. The objective of this work is to formulate an alkaline cleaning solution and characterize its efficiency on particle and BTA removal. The cleaning solution studied consists of tetra methyl ammonium hydroxide (TMAH) as the cleaning agent and arginine as the chelating agent. The removal of BTA is characterized using contact angle measurements and electrochemical techniques. The proposed cleaning solution showed good ability in removing BTA and silica particles from the copper surface and also yielded a lower surface roughness. Arginine facilitates complexing of Cu ions thereby preventing redeposition. [Copyright &y& Elsevier]

Abstract: In this paper, a series of comparative etching experiments on preparing inverted pyramids of silicon solar cells have been carried out using tetramethyl ammonium hydroxide (TMAH) and potassium hydroxide (KOH) at different etchant concentrations and temperatures on a patterned (100) Si. These experiment results show that TMAH solution has higher undercut rate and lower (100) plane etch rate than KOH solution, and the (111)/(100) etch rate ratio of TMAH is two to three times that of KOH solution. Additionally, etch rate of SiO2 mask is an order of magnitude lower in TMAH than in KOH. Besides, surface morphology analysis indicates that TMAH etching can obtain much higher quality inverted pyramids of sharp vertex, smooth (111) sidewall and uncontaminated surface than KOH etching, which makes TMAH etching samples show better antireflection properties. Finally, the minimum reflectivity of TMAH etching sample low as 1.8% is obtained for inverted pyramids covered with SiO2 reflectivity coating. So the study reveals that TMAH is more attractive for the preparation of inverted pyramids than KOH. [Copyright &y& Elsevier]

Abstract: A simple method was proposed for mercury cold vapor generation (CVG) in tetramethylammoniumhydroxide (TMAH) solution for speciation analysis of ultratrace inorganic mercury and total mercury in biological samples by inductively coupled plasma mass spectrometry (ICP-MS). Prior to analysis, 100–300mg of the biological sample was accurately weighed into a conical tube. Then, 2mL of 25% (m/v) TMAH solution was added to the sample, incubated at room temperature for several hours (hair, 3h), and diluted to 25mL with water. Finally, inorganic mercury was directly determined by CVG-ICP-MS, while microwave-assisted oxidation with H2O2 was needed for total mercury detection. The concentration of organic mercury, mainly methylmercury, was obtained by difference of total mercury and inorganic mercury. Only one calibration curve against mercury aqueous standards in 2% TMAH medium was needed for both procedures. Optimum conditions for mercury CVG, as well as sample preparation and microwave-assisted digestion were investigated in detail. A limit of detection (LOD, 3σ) of 3ngL−1 was obtained and the linear working range was 0.1–100μgL−1. Validation data were provided based on the analysis of water samples, as well as a CRM human hair sample (GBW 070601). This is a simple, rapid, ultrasensitive and relatively green method for the determination of mercury in water and biological samples. [Copyright &y& Elsevier]

Abstract: Wet chemical etching of Si(100) and Si(110) wafers in TMAH solutions containing Triton X-100 and alcohol additives was studied in a wide range of alcohol concentrations. TMAH solutions containing butanol-2 and ternary solutions composed of TMAH+Triton+alcohol, used in the experiments, had not been investigated before. The phenomena associated with the presence of surfactant and alcohol additives in etching solutions were analyzed and the mechanism including co-solving of surfactant molecules in alcohol and interplay in the adsorbing mechanism was proposed. The influence of these phenomena on the etching rates and morphologies of Si(100) and Si(110) was discussed. The addition of alcohol, especially butanol-2, to a TMAH solution resulted in significant improvement of the etched surface finish. The roughness of Si(110) surfaces etched in TMAH+butanol solutions was superior to the roughness of the surfaces etched in TMAH+Triton. The best surface roughness parameters of Si(110) (Ra=0.0322μm and RMS=0.0549μm), measured with an optical profilometer on the area of 1.6mm×1.6mm, were achieved after etching in a ternary solution of TMAH+Triton+butanol. This solution appears to be a good candidate in applications where high quality finish of etched surfaces is required on a substantially high area. [Copyright &y& Elsevier]

Abstract: A simple and rapid analytical method to measure total iodine in seawater using sector-filed ICP-MS is presented here. The new method avoided tedious and complicated organic iodine decomposing and redox treatment. In addition, no pre-concentration and separation operations are needed. The seawater was diluted 100-fold with 0.5% TMAH prior to SF-ICP-MS analysis. Te was added as internal standard. Due to the high sensitivity of SF-ICP-MS, excellent detection limit of 0.23ngml−1 in original seawater was obtained. By applying this newly developed method, for the first time, the total iodine concentrations in Japanese coastal seawaters in 14 estuaries were investigated. An average value of 58.26±6.30ngml−1 (n=59) for total iodine concentration was obtained for future study on the estimation of sediment–water distribution coefficients and the concentration ratios from water to organisms in Japanese coastal marine environment. [Copyright &y& Elsevier]

Abstract: Amino acid was mixed with silica and tetramethylammonium hydroxide (TMAH) to favor pyrolysis of amino acid monomer. The pyrolysis products formed from amino acid monomer were using GC/MS and GC. 20 amino acids of alanine, arginine, asparagine, aspartic acid, cysteine, glutamic acid, glutamine, glycine, histidine, isoleucine, leucine, lysine, methionine, phenylalanine, proline, serine, threonine, tryptophan, tyrosine, and valine were analyzed. The pyrolysis products were divided into cyclic and non-cyclic products. Among the 20 amino acids, arginine, asparagine, glutamic acid, glutamine, histidine, lysine, and phenylalanine generated cyclic pyrolysis products of the monomer. New cyclic pyrolysis products were formed by isolation of amino acid monomers. They commonly had polar side functional groups to 5-, 6-, or 7-membered ring structure. Arginine, asparagine, glutamic acid, glutamine, histidine, and phenylalanine generated only 5- or 6-membered ring products. However, lysine generated both 6- and 7-membered ring compounds. Variations of the relative intensities of the cyclic pyrolysis products with the pyrolysis temperature and amino acid concentration were also investigated. [Copyright &y& Elsevier]

Abstract: The scalloping removal on the silicon via sidewalls after a Deep Reactive Ion Etching (DRIE) by the so-called STiGer process has been achieved using a low concentrated alkaline solution at low temperature. Post-etching to reduce sidewall roughness was carried out in both KOH and TMAH-based solutions where the mass concentrations varied between 2% and 5%. The influence of IsoPropyl Alcohol (IPA) addition and the behavior of alkaline mixtures at two different temperatures (10°C and 22°C) were also investigated. The production of silicon surfaces free of micro-pyramids (also known as hillocks) has gone through the optimization of every etching parameter. SEM pictures have qualitatively evidenced the scalloping reduction and the shapes evolution in time, whereas AFM measurements performed on the silicon via sidewalls have allowed a quantification of the smoothing effect of the alkaline solutions. The Root Mean Square roughness (R q) of the reference (sample with scalloped sidewalls without smoothing treatments) was thus compared with the one for wet alkaline treated samples. The results demonstrate that the etched via sidewalls are 60 times smoother. This value is, to our knowledge, the most important smoothing effect described in the literature. [Copyright &y& Elsevier]

Abstract: A simple analytical procedure for the determination of Cu and Fe in biodiesel samples by electrothermal atomic absorption spectrometry is proposed. An aliquot of the sample is simply mixed with tetramethylammonium hydroxide (TMAH) and heated to 90°C for 5min. Pyrolysis and atomization temperatures were optimized through pyrolysis and atomization curves. The high pyrolysis temperature adopted, of 1000°C, certainly helped minimizing potential interferences. Even though, calibration should be carried out with aqueous standard solutions in the presence of the TMAH. The detection limits (3s, n =10), in the sample, were quite low 15ngg−1 and 24ngg−1 for Cu and Fe, respectively. Seven biodiesel samples, produced from different raw materials, including vegetable seed, frying oil and animal fat were analyzed. Accuracy was validated by applying the recovery test to two samples, enriching the samples with two concentration levels (recoveries from 105% to 120%). The precision, expressed by the relative standard deviation was less than 3% for Cu and less than 7% for Fe. Copper could be quantified in two and Fe in three of the seven samples. The biodiesel sample from fodder turnip was especially rich in the analytes in comparison to the other samples. [Copyright &y& Elsevier]

Abstract: Levoglucosan is one of the most abundant pyrolysis products formed from carbohydrates and a good chemical tracer of biomass combustion. Formation of levoglucosan from glucose, maltose, maltotriose, cellulose, and starch with and without silica and tetramethylammonium hydroxide (TMAH) by pyrolysis was studied. TMAH was employed as a methylating agent. Influence of the sizes and spatial structures of the carbohydrates on the formation of levoglucosan by pyrolysis was examined. Levoglucosan was formed only when TMAH was not used. By adding silica to glucose, levoglucosan was not formed. When maltose, maltotriose, and cellulose were mixed with silica, relative abundances of levoglucosan decreased. On the contrary, for starch, the relative abundance of levoglucosan was increased by adding silica. Silica effect on the formation of levoglucosan was explained with hydrogen bonds between silica and carbohydrates. [ABSTRACT FROM AUTHOR]

Abstract: One of the difficulties encountered in implementing optical interconnect between stacked dies in a single IC chip is to fabricate a high quality rear 45°micromirror. This rear 45°micromirror works in conjunction with the front 45°micromirror to achieve the vertical transmission of the optical signal. In this paper, a detail study is conducted on the rear 45°micromirror, which is made from a thin silicon membrane which is anchored by silicon blocks. The fabrication technique of this micromirror is described. The roughness of the rear 45°micromirror surface is about 10 nm measured directly by AFM. Finally the optical test arrangement and test results are shown and discussed. [ABSTRACT FROM AUTHOR]

Abstract: The amount of pollutants produced during manufacturing processes of thin-film transistor liquid crystal display (TFT-LCD) substantially increases due to an increasing production of the opto-electronic industry in Taiwan. This study presents the treatment performance of one aerobic and one anoxic/oxic (A/O) sequencing batch reactors (SBRs) treating synthetic TFT-LCD wastewater containing dimethyl sulfoxide (DMSO), monoethanolamine (MEA), and tetra-methyl ammonium hydroxide (TMAH). The long-term monitoring results for the aerobic and A/O SBRs demonstrate that stable biodegradation of DMSO, MEA, and TMAH can be achieved without any considerably adverse impacts. The ammonium released during MEA and TMAH degradation can also be completely oxidized to nitrate through nitrification in both SBRs. Batch studies on biodegradation rates for DMSO, MEA, and TMAH under anaerobic, anoxic, and aerobic conditions indicate that effective MEA degradation can be easily achieved under all three conditions examined, while efficient DMSO and TMAH degradation can be attained only under anaerobic and aerobic conditions, respectively. The potential odor problem caused by the formation of malodorous dimethyl sulfide from DMSO degradation under anaerobic conditions, however, requires insightful consideration in treating DMSO-containing wastewater. [Copyright &y& Elsevier]

Abstract: This review outlines and discusses the recent development of thermochemolysis (or thermally assisted hydrolysis and methylation (THM)) since the review paper by Challinor in this journal in 2001. The concept and practice of thermochemolysis using quaternary ammonium base reagents, e.g., tetramethylammonium hydroxide (TMAH), is given. The application review is categorized based on either the class of compounds, or popular sample types, e.g., soils, pollen etc. using thermochemolysis gas chromatography–mass spectrometry (GC–MS). Quantitative analysis, a relatively new aspect of thermochemolysis, is discussed separately, where appropriate, at the end of some of application sections. The wide variety of applications includes synthetic polymers, lipids, materials in art and conservation, lignin, carbohydrates, amino acids, proteins and nucleic acids, flavonoids, soil/sediments, atmosphere particulates, human samples, and others. A section is devoted to chemometric techniques and data analysis of thermochemolysis products. [ABSTRACT FROM AUTHOR]

Abstract: FinFETs with ultra-large height-to-width ratio have been processed on (110) bulk silicon wafers by employing crystallographic etching of silicon with TMAH, which results in nearly vertical sidewalls with a (111)/〈112〉 surface orientation. Tall fins, which corresponds to wide transistor channels per single fin offer more efficient use of the silicon area and improved performance for multi-fin devices in high-frequency analog applications. N-channel FinFETs with 1.9-nm-wide fins demonstrate the downscaling potential of the technology and devices with a height of the active part of the fin of 625nm have the largest aspect-ratio of the fins reported thus far. Both devices with highly and moderately scaled fin-widths exhibit excellent subthreshold performance while electrons have higher mobility in 15-nm-wide FinFETs, which gives them larger on-state currents. The comparison between FinFETs and wide tri-gate devices shows that FinFETs have better current drivability in this simple process, even with larger source/drain series resistances. The differences in threshold voltage and low-field electron mobility between 1.9-nm-wide and 15-nm-wide FinFETs have been related to the increase in subband energies due to carrier confinement in the extremely narrow fins. [Copyright &y& Elsevier]

Abstract: This letter proposes a model to explain the accused macroscopic effects caused by a small addition of a surfactant, such as Triton X-100, to a typical alkaline etchant, such as tetramethyl ammonium hydroxide (TMAH), for applications of silicon micromachining in Micro Electro Mechanical Systems (MEMS). The effects include dramatic changes in the etched profiles and small to large reductions in the etch rate and surface roughness, depending on the surface orientation of silicon and the etchant concentration. We propose that the surfactant forms a thin, adsorbed, filter layer at the silicon surface, reducing the number of reactant molecules that may reach the surface from the etchant phase and affecting the number of performed reactions. The orientation and etchant-concentration dependence of the surfactant layer thickness is determined using spectroscopic ellipsometry. The model is consistent with the most widely accepted mechanism for the etching process and overall observed phenomena in general. [Copyright &y& Elsevier]

Abstract: This paper discusses the dependence of the etching properties of single-crystal silicon in tetramethyl ammonium hydroxide (TMAH) solutions containing small amounts of Triton X-100 surfactant on the preferential adsorption of the surfactant in relation to different surface orientations. In order to evaluate the orientation-dependent adsorption of the surfactant molecules on Si{110} and Si{100}, we use spectroscopic ellipsometry (SE) for the first time, finding that the surfactant is preferentially adsorbed on {110}. This is further confirmed by studying convex corner undercutting behavior. The dependence of the adsorbed surfactant thickness on various conditions, such as the surfactant bath time, temperature and ultrasonic agitation is considered. The dependence of the etch rate and the surface roughness in TMAH on the layer thickness shows that a pre-adsorbed surfactant layer affects these etching characteristics in a similar way as the direct addition of the surfactant to the etchant (TMAH+Triton), indirectly demonstrating that the surfactant is adsorbed at the interface during etching in TMAH+Triton. The pre-adsorbed surfactant layer produces a different evolution of the etching profile, showing potentially novel structures in MEMS. [Copyright &y& Elsevier]

Abstract: The effect of different surface morphologies obtained by anisotropic etching on the light trapping and short circuit current of single crystalline silicon solar cells was investigated. The anisotropic texturing of a (100) silicon surface was performed using potassium hydroxide (KOH) solution and/or tetramethylammonium hydroxide (TMAH) solution including isopropyl alcohol (IPA) additive or tertiary butyl alcohol (TBA) additive. Texturing in TMAH solution formed smaller pyramids on the textured surface compared with texturing in KOH solution. Although the textured samples showed similar reflectances (except in the case of the TBA additive), they showed different short circuit currents. Texturing in KOH/TMAH solution led to a 9.6% increase in short circuit current compared with texturing in KOH/IPA solution, a typical etchant in commercial processes. Based on these results, the reflectivity has no simple proportionality relationship to the short circuit current, and the short circuit current of silicon solar cells should be the criterion used in evaluating texturing effects on reducing reflectance and forming a sound junction with high collection efficiency. [Copyright &y& Elsevier]

Abstract: In this research, we have studied the various shapes of corner compensation structures such as triangles, squares as well as 〈110〉 and <100> oriented beams for use with pure and surfactant added tetramethyl ammonium hydroxide (TMAH) solutions. The etchant concentrations of 10%, 20% and 25% were used with and without a small amount of surfactant NC-200 (0.1% of the total volume of the etchant). This surfactant contains 100% polyoxyethylene-alkyl-phenyl-ether with a hydrophobic head ‘CH3(CH2)8–C6H4’ and a hydrophilic tail ‘O(CH2CH2O)20H’. As the etching characteristics (such as etch rate, convex corner undercutting and etching anisotropy) of pure TMAH change dramatically when a small amount of surfactant is added, all the designs proposed for pure TMAH (or KOH) cannot be adopted for surfactant added TMAH. Among all the compensating designs, the triangular shaped geometry is found to be the optimal choice for the surfactant added 25% TMAH solution. The optimized design is successfully used for demonstrating the fabrication of grooves for chip isolation and mesa structures surrounded by bent V-grooves where limited space is available for the compensating pattern. Furthermore, the NC-200 added 25% TMAH was also used to fabricate microfluidic channels, microstructures with rounded concave and sharp convex corners, and a 45° mirror with smooth sidewalls. [Copyright &y& Elsevier]

Abstract: This paper presents a novel technique of fabricating rear 45° micromirror which is located on the upper die to direct a vertical optical beam from the bottom die to propagate horizontally in the upper die. The fabrication of the 45° micromirror is based on anisotropic wet etching on (100) crystalline silicon surface. By using surfactant NCW-1002 in low concentration TMAH (2.5% to 10%) smooth (110) 45° micromirrors can be fabricated. Together with a suitable orientation of the back side etch window, this 45° micromirror provides the framework for fabricating the rear 45° micromirror. [Copyright &y& Elsevier]

Abstract: Etching rates and morphologies of Si wafers with different crystallographic orientations etched in pure TMAH and TMAH with isopropyl alcohol have been analysed. IPA addition caused significant improvement in the morphology of some etched surfaces. Similar effects had been already observed in KOH+IPA solutions. The factors affecting the etching results, including hydroxide and surfactant concentrations, surface tension and bonds arrangement on (hkl) planes have been analysed. [Copyright &y& Elsevier]

Abstract: A simple method for sample preparation of biological samples for trace elements determination by inductively coupled plasma mass spectrometry (ICP-MS) is described. Prior to analysis, 75mg of the biological samples were accurately weighed into (15mL) conical tubes. Then, 1mL of 50% (v/v) tetramethylammonium hydroxide (TMAH) solution was added to the samples, incubated at room temperature for 12h and the volume made up to 10mL with a solution containing 0.5% (v/v) HNO3, 0.01% (v/v) Triton® X-100 and 10μgL−1 of Rh. After preparation samples may be stored at −20°C during 3 days until the analysis by ICP-MS. With these conditions, the use of the dynamic reaction cell was only mandatory for chromium determination. Method detection limits were 0.2145, 0.0020, 0.0051, 0.0017, 0.0027, 0.0189, 0.02, 0.5, 0.1, 0.0030, 0.0043, 0.0066, 0.0009, 0.020, 0.0043, 0.1794, 0.1μgg−1 for Al, As, Ba, Cd, Co, Cr, Cu, Fe, Mg, Mn, Mo, Pb, Sb, Se, Sr, V and Zn, respectively. Validation data are provided based on the analysis of six certified reference materials (CRMs) purchased from the National Institute of Standards and Technology (NIST) and National Research Council Canada (NRCC). Additional validation was provided by the analysis of brain, kidney, liver and heart samples collected from rats and analyzed by the proposed method and by using microwave digestion. [Copyright &y& Elsevier]

Abstract: Thermochemolysis–gas chromatography/mass spectrometry (GC/MS) in the presence of tetramethylammonium hydroxide (TMAH) was applied to the determination of alkylphenols in Ginkgo biloba leaves directly using a vertical microfurnace pyrolyzer. TMAH thermochemolysis–GC enabled the highly sensitive determination of alkylphenols including ginkgolic acids and ginkgols in G. biloba leaves as their methyl derivatives on the resulted pyrograms. On the basis of their peak areas, the contents of the alkylphenols in G. biloba leaf sample were rapidly and precisely determined without using any tedious and time-consuming pretreatment. [Copyright &y& Elsevier]

Abstract: The effect of the presence of palladium ions in a highly alkaline precipitation system on the formation of iron oxides was investigated using X-ray powder diffraction (XRPD), Mössbauer and FT-IR spectroscopies, field emission scanning electron microscopy (FE-SEM) and energy dispersive X-ray spectroscopy (EDS). Acicular α-FeOOH particles precipitated in a highly alkaline medium with the addition of tetramethylammonium hydroxide (TMAH) were used as reference material. The initial addition of palladium ions to that precipitation system had a significant effect on the formation of iron oxide phases and their properties. In the presence of palladium ions, the initially formed α-FeOOH has been transformed to α-Fe2O3 crystals in the form of hexagonal bipyramids via a dissolution–reprecipitation mechanism with a simultaneous formation of metallic palladium nanoparticles. These palladium nanoparticles acted as a catalyst for the reductive dissolution of α-Fe2O3 particles and the formation of Fe3O4 crystals in the form of octahedrons. Increase in the initial concentration of palladium ions in the precipitation system accelerated the transformation process α-FeOOH→α-Fe2O3 →Fe3O4 and influenced changes in the shape of α-Fe2O3 and Fe3O4 particles. [Copyright &y& Elsevier]

Abstract: Cationically modified polyacrylamides (cPAA) are commonly used flocculants in sewage water treatment processes. Therefore, those compounds are quantitatively important contaminants in sewage sludges, which were deposited on agricultural soils as fertilizers in the past and even today in many countries. In order to monitor environmental pathways and to correlate ecotoxicological effects with quantitative data, there is a necessity for methodologies for quantitative analyzes of technically applied polyacrylamides. The present investigation provides a fundamental proof of the verifiability of cPAA in particulate samples by on-line thermochemolysis-GC–MS in presence of tetramethyl ammonium hydroxide. This methodological approach induces degradation of cPAA to glutarimide related structures. Experiments were carried out on pure cPAA, spiked sediments and sewage sludges. The results revealed a linear correlation between thermochemically degraded quantities of cPAA and abundances of glutarimide related degradation products as well as a theoretical limit of detection of 250mg/kg, which is sufficient for corresponding analyzes concerning sewage sludges. Thermochemolysis experiments on polyacrylamide and anionically modified derivates revealed the same glutarimide related degradation products as obtained by degradation of cPAA. [Copyright &y& Elsevier]