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181.
Yoichi Makimizu Nhat Truong Nguyen Jiri Tucek Hyo-Jin Ahn JeongEun Yoo Mahshid Poornajar Imgon Hwang Stepan Kment Prof. Dr. Patrik Schmuki 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(12):2685-2692
Photoelectrochemical (PEC) water splitting is a promising method for the conversion of solar energy into chemical energy stored in the form of hydrogen. Nanostructured hematite (α-Fe2O3) is one of the most attractive materials for a highly efficient charge carrier generation and collection due to its large specific surface area and the short minority carrier diffusion length. In the present work, the PEC water splitting performance of nanostructured α-Fe2O3 is investigated which was prepared by anodization followed by annealing in a low oxygen ambient (0.03 % O2 in Ar). It was found that low oxygen annealing can activate a significant PEC response of α-Fe2O3 even at a low temperature of 400 °C and provide an excellent PEC performance compared with classic air annealing. The photocurrent of the α-Fe2O3 annealed in the low oxygen at 1.5 V vs. RHE results as 0.5 mA cm−2, being 20 times higher than that of annealing in air. The obtained results show that the α-Fe2O3 annealed in low oxygen contains beneficial defects and promotes the transport of holes; it can be attributed to the improvement of conductivity due to the introduction of suitable oxygen vacancies in the α-Fe2O3. Additionally, we demonstrate the photocurrent of α-Fe2O3 annealed in low oxygen ambient can be further enhanced by Zn-Co LDH, which is a co-catalyst of oxygen evolution reaction. This indicates low oxygen annealing generates a promising method to obtain an excellent PEC water splitting performance from α-Fe2O3 photoanodes. 相似文献
182.
This paper examines the cycling behavior of a deterministic and a stochastic version of the economic interpretation of the Lotka–Volterra model, the Goodwin model. We provide a characterization of orbits in the deterministic highly non-linear model. We then study a stochastic version, with Brownian noise introduced via a heterogeneous productivity factor. Existence conditions for a solution to the system are provided. We prove that the system produces cycles around a unique equilibrium point in finite time for general volatility levels, using stochastic Lyapunov techniques for recurrent domains. Numerical insights are provided. 相似文献
183.
184.
Lipases and esterases are important catalysts with wide varieties of industrial applications. Although many methods have been established for detecting their activities, a simple and sensitive approach for picogram detection of lipolytic enzyme quantity is still highly desirable. Here we report a lipase detection assay which is 1000-fold more sensitive than previously reported methods. Our assay enables the detection of as low as 5 pg and 180 pg of lipolytic activity by direct spotting and zymography, respectively. Furthermore, we demonstrated that the detection sensitivity was adjustable by varying the buffering capacity, which allows for screening of both high and low abundance lipolytic enzymes. Coupled with liquid chromatography-mass spectrometry, our method provides a useful tool for sensitive detection and identification of lipolytic enzymes. 相似文献
185.
Tang Guangxian Shafee Ahmad Nam Nguyen Dang Tlili Iskander 《Journal of Thermal Analysis and Calorimetry》2021,143(6):4249-4260
Journal of Thermal Analysis and Calorimetry - Electrical sensor has been considered in the current attempt. Combination of buoyancy, electric and radiative forces has been included in the governing... 相似文献
186.
Mohanad A. Hussein Dr. Uyen P. N. Tran Dr. Vien T. Huynh Dr. Junming Ho Dr. Mohan Bhadbhade Prof. Dr. Herbert Mayr Dr. Thanh V. Nguyen 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(4):1471-1475
Tropylium bromide undergoes noncatalyzed, regioselective additions to a large variety of Michael acceptors. In this way, acrylic esters are converted into β-bromo-α-cycloheptatrienylpropionic esters. The reactions are interpreted as nucleophilic attack of bromide ions at the electron-deficient olefins and the approach of the tropylium ion to the incipient carbanion. Quantum chemical calculations were performed to elucidate the analogy to the amine- or phosphine-catalyzed Rauhut–Currier reactions. Subsequent synthetic transformations of the bromo-cycloheptatrienylated adducts are reported. 相似文献
187.
188.
Journal of Nonlinear Science - We prove that if the local second-order structure function exponents in the inertial range remain positive uniformly in viscosity, then any spacetime $$L^2$$ weak... 相似文献
189.
Some derivatives of an homologous series of 4-aIkoxy-benzoyloxy-4′-cyanotolanes are synthesized. Two of them exhibit a stable nematic reentrant phase at atmospheric pressure. 相似文献
190.
Bui Dac Dung Trinh Van Giap Tibor Kovacs Tran Ngoc Toan Le Dinh Cuong Tran Khanh Minh Nguyen Huu Quyet Nguyen Van Khanh 《Journal of Radioanalytical and Nuclear Chemistry》2014,299(3):1943-1948
Mineral sands are mined in several countries to supply to the titanium and zircon producing industries. Coastal black mineral sands usually contain, besides ilmenite (FeTiO3) and rutile (TiO2), radioactive minerals such as zircon (ZrSiO4) and monazite (RePO4). Radon and thoron activity concentration originated from natural radioactive contents of the black mineral sand was monitored at the extraction and processing for black minerals in the coastal areas of Ha Tinh Province, one of the around 40 coastal mineral sand deposits in Vietnam. The survey was carried out with the Raduet chambers made by Radosys Ltd—Hungary. The obtained results for 25 investigated points show that the measured values are not high in the residential houses and in case of the sand extraction site as well. At the titanium processing plant the measured values were higher than outside the facility (Radon: 18–55 Bq/m3 with average of 34 Bq/3 and Thoron 33–118 Bq/m3 with average of 58 Bq/m3) but still comparable to the average concentration of the world published by UNSCEAR. The typical outdoor levels of radon and thoron gas are each of the order of 10 Bq/m3. Although the radon concentrations were low in the zircon and titanium processing plants, the thoron concentrations in the houses for separating rutile and zircon were very high. At zircon processing factory, the thoron concentration could reach 2,931 Bq/m3 and the estimated annual effective dose would be 21.4 mSv/a. Intervention has to be taken in order to reduce the thoron level in this factory since the level of thoron and its progenies corresponding to an annual occupational effective dose is beyond the action level of 6 mSv/a. 相似文献