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91.
Pengfei Jiang Fuwei Jiang Mufei Yue Jing Ju Chunling Xu Rihong Cong Tao Yang 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(18):6039-6043
Intergrowth oxides, like Aurivillius, Ruddlesden–Popper phase, comprise functional layers and exhibit interesting physical properties. The hitherto known intergrowth structures mainly were composed of closed‐packing of oxygen ions, and it is very challenging to develop new types of intergrowth structures. We proposed the possible match between the tridymite and grossite, both of which are purely tetrahedra‐based structures. We synthesized Ca2PbGa8O15 ((Ca0.5Pb0.5Ga2O4)2(CaGa4O7)) and its structure was solved by ab‐initio method. Pb2+ is vitally important to stabilize this first example of tetrahedra‐based intergrowth oxide. The appropriate size difference between Pb2+ and Ca2+ causes the layered type cationic ordering, and reduced the thermodynamic potential, in addition, the high hybridization between Pb 6s6p and O 2p orbitals further consolidate the covalency of the tetrahedra‐base framework. 相似文献
92.
A. Cattoni 《Applied Surface Science》2008,254(9):2720-2724
In analogy with the case of Sr on Si [Y. Liang, S. Gan, M. Engelhard, Appl. Phys. Lett. 79 (2001) 3591], we studied surface crystallinity and oxidation behaviour of clean and Ba terminated Ge(1 0 0) surfaces as a function of oxygen pressure and temperature. The structural and chemical changes in the Ge surface layer were monitored by LEED, XPS and real-time RHEED. In contrast to the oxidation retarding effect, observed for 1/2 monolayer of Sr on Si, the presence of a Ba termination layer leads to a pronounced increase in Ge oxidation rate with respect to clean Ge. In fact, while the Ge(1 0 0) surface terminated with 1/2 ML Ba amorphizes for a pO2 of 10−2 Torr, LEED indicates that clean Ge forms a thin (4.5 Å), 1 × 1 ordered oxide upon aggressive O2 exposure (150 Torr, 200 °C, 30 min). We briefly discuss the origins for the difference in behaviour between Ba on Ge and Sr on Si. 相似文献
93.
In this work, the influence of Si/SiO2 interface properties, interface nitridation and remote-plasma-assisted oxidation (RPAO) thickness (<1 nm), on electrical performance and TDDB characteristics of sub-2 nm stacked oxide/nitride gate dielectrics has been investigated using a constant voltage stress (CVS). It is demonstrated that interfacial plasma nitridation improves the breakdown and electrical characteristics. In the case of PMOSFETs stressed in accumulation, interface nitridation suppresses the hole traps at the Si/SiO2 interface evidenced by less negative Vt shifts. Interface nitridation also retards hole tunneling between the gate and drain, resulting in reduced off-state drain leakage. In addition, the RPAO thickness of stacked gate dielectrics shows a profound effect in device performance and TDDB reliability. Also, it is demonstrated that TDDB characteristics are improved for both PMOS and NMOS devices with the 0.6 nm-RPAO layer using Weibull analysis. The maximum operating voltage is projected to be improved by 0.3 V difference for a 10-year lifetime. However, physical breakdown mechanism and effective defect radius during stress appear to be independent of RPAO thickness from the observation of the Weibull slopes. A correlation between trap generation and dielectric thickness changes based on the C-V distortion and oxide thinning model is presented to clarify the trapping behavior in the RPAO and bulk nitride layer during CVS stress. 相似文献
94.
Aurélie Rolle Helen Seymour Pascal Roussel Annick Rubbens Rose-Noëlle Vannier 《Ionics》2008,14(6):477-482
The Ba2In2 − x
Sn
x
O5 + x/2 solid solution was confirmed up to x = 1 by solid-state reaction. X-ray diffraction at room and at elevated temperatures, Raman scattering and impedance spectroscopy
were used to characterise the samples. The structure refinement of the composition x = 0.1 from neutron diffraction data reveals that tin is preferentially located in the tetrahedral layers of the brownmillerite.
Paper presented at the 11th EuroConference on the Science and Technology of Ionics, Batz-sur-Mer, Sept. 9–15, 2007 相似文献
95.
《Electroanalysis》2018,30(8):1659-1668
PAMAM dendrimer/reduced graphene oxide nanocomposite modified pencil graphite electrode (PAMAM/RGO/PGE) was used to fabricate an electrochemical DNA biosensor for determination of Rituxan (RTX) at low concentrations, for the first time. The fabricated biosensor was characterized with FE‐SEM, EIS, and CV techniques. The ds‐DNA/PAMAM/RGO/PGE was used as a working electrode to study the interaction between the RTX and salmon sperm ds‐DNA by DPV technique. Because of the interaction between the drug and DNA leads to a decrease in the guanine oxidation peak current, it was used as an indicator for the determination of the RTX. Under the optimized experimental conditions, a wide linear relationship between RTX concentration and guanine signal was obtained within the range of 7.0 to 60.0 μmol L−1 and 60.0 to 300.0 μmol L−1 with a low detection limit (0.56 μmol L−1). To clarify the interaction mechanism between the RTX and the ds‐DNA, DPV and UV‐Vis measurements were used. The reproducibility, stability, and performance of the constructed biosensor was examined by quantitative measuring RTX in pharmaceutical and human serum samples with good precision (RSD; 2.0–6.0 %) and acceptable recoveries (100.04–101.95 %). 相似文献
96.
Ferran Sabaté Javier Navas Maria J. Sabater Avelino Corma 《Comptes Rendus Chimie》2018,21(3-4):164-173
The mechanism of the oxidative [3+2] cycloaddition of alkenes with anhydrides using oxygen as an oxidant to synthesize γ-lactones has been studied using a heterogeneous dual copper-manganese–based catalyst. The cyclization takes place through two coexisting reaction mechanisms, the involvement of different reaction intermediates and a clear synergistic effect between copper and manganese. In fact it appears that CuO clusters dispersed on the surface of a manganese-based oxide increase the redox capability of manganese ions and leads to an increase in the release of oxygen from the surface. 相似文献
97.
Multi-domained heteroepitaxial rutile-phase TiO2 (1 0 0)-oriented films were grown on Si (1 0 0) substrates by using a 30-nm-thick BaF2 (1 1 1) buffer layer at the TiO2–Si interface. The 50 nm TiO2 films were grown by electron cyclotron resonance oxygen plasma-assisted electron beam evaporation of a titanium source, and the growth temperature was varied from 300 to 600 °C. At an optimal temperature of 500 °C, X-ray diffraction measurements show that rutile phase TiO2 films are produced. Pole figure analysis indicates that the TiO2 layer follows the symmetry of the BaF2 surface mesh, and consists of six (1 0 0)-oriented domains separated by 30° in-plane rotations about the TiO2 [1 0 0] axis. The in-plane alignment between the TiO2 and BaF2 films is oriented as [0 0 1] TiO2 || BaF2 or [0 0 1] TiO2 || BaF2 . Rocking curve and STM analyses suggest that the TiO2 films are more finely grained than the BaF2 film. STM imaging also reveals that the TiO2 surface has morphological features consistent with the BaF2 surface mesh symmetry. One of the optimally grown TiO2 (1 0 0) films was used to template a CrO2 (1 0 0) film which was grown via chemical vapor deposition. Point contact Andreev reflection measurements indicate that the CrO2 film was approximately 70% spin polarized. 相似文献
98.
Hiroshi Takahashi Susumu Yonezawa Masayuki Kawai 《Journal of fluorine chemistry》2008,129(11):1114-1118
Cerium-containing oxide fluoride glasses CeF3-BaF2-AlF3-SiO2 were prepared under CO and Ar atmospheres. The glass prepared in a CO atmosphere exhibited blue emission under UV irradiation because the hydrolysis of CeF3 to a Ce4+-containing compound during heating process was controlled. The emission spectrum was separable into three peak components by peak analysis. X-ray photoelectron spectroscopy (XPS) spectra were measured to investigate the valency of the elements in the glass. Oxide and fluoride ions in the glass respectively have different electronic states from those in CeO2 and CeF3. The electronic state of cerium ion in the oxide fluoride glass differed from that in CeO2 and CeF3. 相似文献
99.
Design and Development of a Non-Enzymatic Electrochemical Biosensor for the Detection of Glutathione
Shrute Kannappan Lakshmishri Prabakaran Noel Nesakumar K. Jayanth Babu Arockia Jayalatha Kulandaisamy Prof. John Bosco Balaguru Rayappan 《Electroanalysis》2023,35(1):e202100650
Glutathione (GSH-reduced form) is a tripeptide that plays a vital role as an antioxidant to remove xenobiotics in the human body and changes in GSH levels are a marker for the progression of various diseases. In this context, a highly sensitive non-enzymatic electrochemical biosensor for the detection of GSH has been developed using reduced graphene oxide Manganese oxide (rGMnO) nanocomposite as the nano-interface. Initially, graphene oxide was synthesized by Hummer's method and then thermally reduced in the presence of MnO2 in a blast furnace to obtain rGMnO nanocomposite. The nanocomposite was characterized to validate its structure and morphological properties via Scanning electron microscopy (SEM), X-ray diffraction (XRD), Raman, and X-ray photoelectron spectroscopy (XPS). Cyclic voltammetry and amperometry studies showed that upon the addition of GSH, the Pt/rGMnO modified working electrode exhibited a linear response in the range of 1–100 μM at an input voltage of −0.62 V. The developed sensor was found to have a sensitivity of 0.3256 μA μM−1 and LOD of 970 nM with a recovery of 92–104 % in real blood serum samples. 相似文献
100.
Jiahui Xian Suisheng Li Hui Su Peisen Liao Shihan Wang Runan Xiang Yawei Zhang Prof. Qinghua Liu Prof. Guangqin Li 《Angewandte Chemie (International ed. in English)》2023,62(30):e202306726
The conversion of industrial exhaust gases of nitrogen oxides into high-value products is significantly meaningful for global environment and human health. And green synthesis of amino acids is vital for biomedical research and sustainable development of mankind. Herein, we demonstrate an innovative approach for converting nitric oxide (NO) to a series of α-amino acids (over 13 kinds) through electrosynthesis with α-keto acids over self-standing carbon fiber membrane with CoFe alloy. The essential leucine exhibits a high yield of 115.4 μmol h−1 corresponding a Faradaic efficiency of 32.4 %, and gram yield of products can be obtained within 24 hours in lab as well as an ultra-long stability (>240 h) of the membrane catalyst, which could convert NO into NH2OH rapidly attacking α-keto acid and subsequent hydrogenation to form amino acid. In addition, this method is also suitable for other nitrogen sources including gaseous NO2 or liquidus NO3− and NO2−. Therefore, this work not only presents promising prospects for converting nitrogen oxides from exhaust gas and nitrate-laden waste water into high-value products, but also has significant implications for synthetizing amino acids in biomedical and catalytic science. 相似文献