CERAMICS INTERNATIONAL
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2024
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IF 5.1
Ning Sun,Tengpeng Wang,Yuhang Du,Xiaojun Ma,Wenkai Xin,Haochen Dang,Xuqiu Xie,Tao Wei,Qinggang Li
Si 3 N 4 ceramics pose a challenge when it comes to the preparation of light-curing pastes with high depth of cure, elevated solid content, and low viscosity. This challenge is primarily attributed to their inherent characteristics, including high absorbance, a high refractive index, and suboptimal sphericity. Consequently, the application of Si 3 N 4 ceramics in 3D printing remains a complex endeavor. To address the intricacies associated with 3D printing using Si 3 N 4 ceramics, our research focuses on the utilization of Tetramethylammonium Hydroxide (TMAH) for pH adjustment in Si 3 N 4 ceramics. This adjustment aims to enhance the stability, curing depth, and viscosity of the slurry. Subsequently, we employ this Si 3 N 4 light-curing slurry for 3D printing, followed by sintering the printed materials. The evaluation includes testing for porosity, density, and flexural strength of the samples. Notably, our efforts yield porous silicon nitride ceramics boasting an impressive density of 1.8299 g/cm 3 , porosity measuring 43.718%, and remarkable flexural strength amounting to 275 MPa.
研究领域:
材料科学
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陶瓷工程
✓ 已验证
产品关联
DOI
高影响因子
APPLIED SURFACE SCIENCE
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2019
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IF 5.155
Jian Shen,Yuandong Chen,Feihu Zhang,Dan Zhang,Yang Gan
Wet etching of Si substrate enables fabrication of sophisticated Si microstructures for a number of applications. However, the detailed anisotropic etching behavior of Si in the alkaline TMAH solutions is still not well understood. In this study, insights into the wet etching behavior of (100) patterned silicon substrate (PSiS) with circular aperture SiO 2 mask in TMAH solutions of varying concentrations (1–25 wt%) are obtained through systematically studying the morphological and crystallographic evolutions of PSiS. Etching in 1 wt% TMAH revealed the widest spectrum of morphological evolutions including the rounded apertures, inverted octahedral frustums, octahedral pyramids, and pyramids. In contrast, etching in 5–25 wt% TMAH revealed features of inverted octahedral frustums, pyramidal frustums, and pyramids. A series of crystallographic planes formed due to anisotropic crystallographic etching were indexed as—C 1 { 3 ¯ 40}, C 2 { 1 ¯ 10}, C 3 { 1 ¯ 1 1 ¯ }, C 4 { 2 ¯ 1 1 ¯ }, and C 5 {1 14 0}, and the etching rates of which were determined to explain the morphological evolution and anisotropic etching mechanism. This work contributes to the controllable fabrication of sophisticated Si microstructures for Si-based optoelectronic devices with potentially enhanced performance.
研究领域:
材料科学
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微纳加工
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半导体工艺
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表面工程
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晶体学
✓ 已验证
DOI
高影响因子
MICROCHEMICAL JOURNAL
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2012
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IF 3.048
Yi Wu,Yong-Ill Lee,Li Wu,Xiandeng Hou
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, 100–300 mg of the biological sample was accurately weighed into a conical tube. Then, 2 mL of 25% (m/v) TMAH solution was added to the sample, incubated at room temperature for several hours (hair, 3 h), and diluted to 25 mL with water. Finally, inorganic mercury was directly determined by CVG-ICP-MS, while microwave-assisted oxidation with H 2 O 2 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 3 ng L − 1 was obtained and the linear working range was 0.1–100 μg L − 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.
研究领域:
分析化学
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环境科学
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生物学
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产品关联
DOI
高影响因子
ACTA PHYSICO-CHIMICA SINICA
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2015
·Vol. 31
·期 10
·1905-1913
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IF 0.852
ZHANG Jia-Han,GUO Gui-Bao,AN Sheng-Li,HAO Yan,ZHANG Dong,YAN Kai-Bo
Poly(vinylidene fluoride)-graft-poly(sulfobetaine methacrylate) (PVDF-g-PSBMA) proton exchange membranes were synthesized via single-step grafting sulfobetaine methacrylate (SBMA) onto PVDF. Benzoyl peroxide (BPO) was the initiator, and the PVDF was initially modified by tetramethylammonium
hydroxide (TMAH) in the liquid phase. Microstructure morphologies and sulfur distributions in the membrane were characterized by Fourier transform infrared (FTIR) spectroscopy and scanning electron microscopy/energy dispersive X-ray spectroscopy (SEM-EDX), respectively. The PVDF formed C=C
double bonds following dehydrofluorination by TMAH. SBMA was grafted onto the modified PVDF backbones, forming a homogeneous sulfur distribution in the interior and exterior of the membrane. Proton conductivities and methanol permeabilities of PVDF-g-PSBMA membranes increased with the increasing
of the TMAH mass fraction in methanol. When the mass fraction was 20%, the proton conductivity of the membrane was 0.0892 S·cm-1 at 20 , and the methanol permeability was 4.04 × 10-7 cm2·s-1 at ambient temperature, respectively.
The membrane exhibited good thermal stability up to 270 , as verified by thermogravimetric analysis (TGA). With this membrane, the peak power density of a direct methanol fuel cell (DMFC) was 17.06 mW·cm-2.
研究领域:
材料科学
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能源工程
✓ 已验证
DOI
高影响因子
ENVIRONMENTAL RESEARCH
·
2024
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IF 7.7
Andong Zhao,Jun Li,Peng Gao,Peng Tang,Tingting Liu,Xin Zhang,Xuming Liu,Cong Chen,Zehao Zhang,Zhaoming Zheng
Tetramethylammonium hydroxide (TMAH), an extensively utilized photoresist developer, is frequently present in ammonium-rich wastewater from semiconductor manufacturing, and its substantial ecotoxicity should not be underestimated. This study systematically investigated the effects of TMAH on the anammox granular sludge (AnGS) system and elucidated its inhibitory mechanisms. The results demonstrated that the median inhibitory concentration of TMAH for anammox was 84.85 mg/L. The nitrogen removal performance of the system was significantly decreased after long-term exposure to TMAH (0 - 200 mg/L) for 30 days ( p < 0.05), but it showed adaptability to certain concentrations (≤ 50 mg/L). Concurrently, the stability of the granules decreased dramatically, resulting in the breakdown of AnGS. Further investigations indicated that TMAH exposure increased the secretion of extracellular polymeric substances but weakened their defense function. The increase in reactive oxygen species resulted in damage to the cell membrane. Reduced activity of anammox bacteria, impeded electron transfer, and changes in enzyme activity suggested that TMAH affected the metabolic activity. Microbiological analysis revealed that TMAH caused a decrease in the abundance of anammox bacteria and a weakening of symbiotic interactions within the microbial community. These results provide valuable guidance for the AnGS system application in chip wastewater treatment.
研究领域:
环境工程
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废水处理
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微生物学
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生物技术
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产品关联
DOI
PubMed
高影响因子
ANALYTICAL AND BIOANALYTICAL CHEMISTRY
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2022
·Vol. 415
·期 5
·887-897
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IF 4.478
Ren Rongfan,Li Hongli,Jiang Qing,Wang Xing,Chen David Da Yong
Characterization of structural isomers of bioactive molecules is important for recognizing their functions, but it has been challenging due to their highly similar structures. As the main bioactive constituents of Panax ginseng , ginsenosides have different structural isomers attributed to the aglycone structure and glycosylation sites as well as stereochemistry of sugar groups attached. This work demonstrated a simple and robust in situ methylation reaction with tetramethylammonium hydroxide (TMAH) using ambient ionization source of direct analysis in real time (DART) to characterize saponin structural isomers. The DART ion source provides favorable conditions to methylate hydroxyl groups of ginsenoside instantaneously with TMAH, and it can ionize the methylated products at the same time. Methylated ginsenoside stereoisomers even with subtle structure differences generated very different mass signals from full-scan MS and tandem MS. High-resolution mass spectrometry aided the assignment of molecular structures of the various precursor and fragment ions from different ginsenosides, which provided structural information for both the aglycone skeleton and the sugar moieties in ginsenosides. The presented method was successfully used for the identification of ginsenosides in Panax ginseng , and saponin isomers were characterized without the need for chromatographic separation and/or tedious offline sample pretreatment. Graphical Abstract
研究领域:
分析化学
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药学
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质谱学
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天然产物化学
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产品关联
DOI
PubMed
高影响因子
Journal of Cleaner Production
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2020
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IF 7.246
Juan Lv,Yan Wang,Mengya Fu,Changyuan Ou,Fan Xiao
Tetramethylammonium Hydroxide (TMAH) is widely used as a developer in the thin-film transistor liquid crystal display (TFT-LCD) industry, which is a corrosive alkaline and neuronal toxic compound. In this study, the performances of combined hydrolysis acidification-aerobic and anaerobic batch reactors for synthetic TMAH wastewater treatment were evaluated. It also investigated the real TMAH wastewater treatment in the anaerobic batch reactor. The batch tests focused on the removal efficiencies and intermediate products of TMAH biodegradation during different processes. Furthermore, microbial community structures were identified. The long-term monitoring of 380 days results demonstrated that TMAH degraded can be stably achieved by hydrolysis acidification-aerobic and anaerobic processes , and the total organic carbon removal efficiencies were both higher than 91%. The pretreatment by hydrolysis acidification process could avoid the inhibition of high concentration TMAH on subsequent aerobic treatment . Main intermediate products during the hydrolysis acidification-aerobic and anaerobic treatments included trimethylamine, dimethylamine, monomethylamine, which can be degraded easily by biotreatment . Consequently, nearly 70% organic nitrogen in the influent TMAH transferred to ammonium or nitrate, while the mineralization of intermediates caused methane and carbon dioxide generation. The study also proposed TMAH degradation pathways by different processes based on the intermediate’s identification. Analysis of 16s rRNA gene sequencing revealed that mixed microbe contributed in TMAH degradation. At the phylum level, proteobacteria and bacteroidetes were abundant in all the reactors. Besides, patescibateria , cloacimonetes and acidobacteria were dominant in anaerobic reactors as well. This study suggests that traditional combined or single activated sludge processes could be used for TMAH-containing wastewater treatment. Especially, anaerobic process may be favored over other processes.
研究领域:
环境科学
·
生物学
✓ 已验证
DOI
高影响因子
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