排序方式: 共有150条查询结果,搜索用时 15 毫秒
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Mohammad Muneer Mohd Saquib Mohd Qamar Detlef Bahnemann 《Research on Chemical Intermediates》2010,36(2):121-125
The photocatalyzed oxidation of indole (1) in an aqueous suspension of titanium dioxide has been investigated and an attempt has been made to identify the products
formed during the photooxidation process by gas chromatographic–mass spectrometric (GC–MS) analysis. Photolysis of an aqueous
solution of indole (1) in the presence of titanium dioxide and oxygen led to the formation of 2,3-dihydroindole-2-one (6) and 1H-indole-2,3-dione (7). A probable pathway for the formation of these products has been proposed. 相似文献
43.
This proposal investigates the influence of the phase fluctuations on the time evolution of entanglement generation in a three-level correlated emission laser (CEL) with injected coherence. The atoms are injected in the cavity with an initial partial coherent superposition of the upper and lower levels. The corresponding phase φ is considered to be randomly distributed around some fixed phase φ0. The fluctuations in phase φ modifies the coherence between the two corresponding atomic levels. Therefore, we observe strong influence of phase fluctuations on the entanglement generation using the injected coherence CEL system. 相似文献
44.
Single Unit Cell Bismuth Tungstate Layers Realizing Robust Solar CO2 Reduction to Methanol
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Liang Liang Fengcai Lei Shan Gao Prof. Yongfu Sun Xingchen Jiao Ju Wu Shaista Qamar Prof. Yi Xie 《Angewandte Chemie (International ed. in English)》2015,54(47):13971-13974
Solar CO2 reduction into hydrocarbons helps to solve the global warming and energy crisis. However, conventional semiconductors usually suffer from low photoactivity and poor photostability. Here, atomically‐thin oxide‐based semiconductors are proposed as excellent platforms to overcome this drawback. As a prototype, single‐unit‐cell Bi2WO6 layers are first synthesized by virtue of a lamellar Bi‐oleate intermediate. The single‐unit‐cell thickness allows 3‐times larger CO2 adsorption capacity and higher photoabsorption than bulk Bi2WO6. Also, the increased conductivity, verified by density functional theory calculations and temperature‐dependent resistivities, favors fast carrier transport. The carrier lifetime increased from 14.7 to 83.2 ns, revealed by time‐resolved fluorescence spectroscopy, which accounts for the improved electron‐hole separation efficacy. As a result, the single‐unit‐cell Bi2WO6 layers achieve a methanol formation rate of 75 μmol g?1 h?1, 125‐times higher than that of bulk Bi2WO6. The catalytic activity of the single‐unit‐cell layers proceeds without deactivation even after 2 days. This work will shed light on designing efficient and robust photoreduction CO2 catalysts. 相似文献
45.
In this paper, we study the effect of cooperative atomic interactions, cavity losses, and pump fluctuations on quantum phase properties of the field in a one-photon micromaser. We consider, initial coherent state of the radiation field and atoms initially in the excited and coherent superposition of their atomic states, respectively. We find that quantum phase properties of the field in a micromaser are highly sensitive to two-atom events and cavity losses. Both contribute to the randomization of the well-defined phase structure associated with the initial coherent state. However, the approach towards the randomization is quite different in the two cases. We also find that the fluctuations, associated with the random injection of the atoms, affect the phase structure of the coherent state. 相似文献
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Shakri Natasa Mohd Salleh Wan Mohd Nuzul Hakimi Wan Khamis Shamsul 《Chemistry of Natural Compounds》2021,57(6):1114-1115
Chemistry of Natural Compounds - 相似文献
47.
Ashok Kumar Chakraborty Mst. Shanjeda Akter M. Ahsanul Haque G. M. Arifuzzaman Khan M. Shamsul Alam 《Journal of Cluster Science》2013,24(3):701-713
A highly efficient and visible light (λ ≥ 420 nm) responsive nanocomposite photocatalyst Co3O4/WO3 was developed by dispersing p-type semiconductor Co3O4 on the surface of n-type semiconductor WO3. The heterojunction Co3O4/WO3 demonstrated higher photocatalytic activity than WO3, Co3O4 and TiO2 nanoparticles for the complete decomposition of 2-propanol in gas phase and phenol in aqueous phase and evolution of CO2 under visible light irradiation. The highest photocatalytic efficiency of the composite Co3O4/WO3 was observed when calcined at 300 °C for 2 h with 4.91 mol% Co3O4/WO3. The enhanced photocatalytic efficiency of the heterojunction was discussed based on the unique relative energy band positions and profound absorption of visible light by the semiconductors. 相似文献
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M.Shamsul Alam 《International Journal of Non》2004,39(8):1343-1357
A modified and compact form of Krylov-Bogoliubov-Mitropolskii (KBM) (Introduction to Nonlinear Mechanics, Princeton University Press, Princeton, NJ, 1947; Asymptotic Methods in the Theory of Nonlinear Oscillations, Gordan and Breach, New York, 1961) unified method (J. Franklin Inst. 339 (2002) 239) is determined for obtaining the transient response of an nth order (n?2) differential equation with small non-linearities. The formula presented in (J. Franklin Inst. 339 (2002) 239) is a changed form of KBM method. For n=2,3,4, some previous formulas were found separately by several authors in terms of amplitude and phase variables; but the formula of Shamsul Alam, J. Franklin Inst. 339 (2002) 239) is derived in terms of some unusual variables instead of amplitudes and phases. The formula of Shamsul Alam, J. Franklin Inst. 339 (2002) 239) is a general form and used arbitrarily to obtain asymptotic solution for n=2,3,4,…. However, a solution obtained by formula Shamsul Alam, J. Franklin Inst. 339 (2002) 239) is transformed to a formal form replacing the unusual variables by amplitude and phase variables. In the present paper, the formula of Shamsul Alam, J. Franklin Inst. 339 (2002) 239) is itself transformed to a usual form (i.e. in terms of amplitude and phase variables). The later form of the formula is similar to most of the previous formulas found by several authors when n=2,3,4. This form of the formula is also generalized and it is easier than those obtained in all previous papers (extension) and identical to that initiated by original contributors (Introduction to Nonlinear Mechanics, Princeton University Press, Princeton, NJ, 1947; Asymptotic Methods in the Theory of Nonlinear Oscillations, Gordan and Breach, New York, 1961). 相似文献
50.
Qamar un Nisa Akbar Ali Muhammad Haleem Khan 《Journal of Radioanalytical and Nuclear Chemistry》2013,295(3):2203-2214
An economical, fast, sensitive and selective method for the determination of uranium (VI) from sulfate media based on the flow injection on-line preconcentration in a minicolumn having amberlite IRA-402 (strong anion exchange) resin is described. Uranium (VI) was selectively adsorbed on the resin as uranyl trisulfate complex from aqueous solution of pH 2 in the minicolumn (2.56 mm i.d. and 7.5 cm in length) at a flow rate of 10 ml min?1. The adsorbed uranyl trisulfate complex was eluted by HClO4 (0.1 mol l?1, 6.5 ml min?1) and mixed with arsenazo-III (0.05 %, 6.5 ml min?1), and passed through the flow through cell of spectrophotometer where its absorbance was measured at 653 nm. Various parameters affecting adsorption and elution of the uranium complex were optimized. For data analyses peak absorbance was used. For 60 and 180 s preconcentration time, enrichment factors (EF) 20 and 40, sampling frequency (SF) 45 and 18 h?1; and detection limits (DL) (3σ) 14.2 and 8.6 μg l?1 were obtained, respectively. To enhance the sensitivity of the system, two minicolumns (described above) were used for simultaneous preconcentration and elution purpose. For 60 and 180 s preconcentration time, EF 30 and 50, SF 42 and 17 h?1 and DL (3σ) 4.4 and 3.44 μg l?1 were obtained, respectively. The effect of various anions and cations was studied for single column manifold. High selectivity of this method was observed. All the anions and cations studied did not interfere up to 330 times higher mass ratio to 300 μg l?1 U (VI) except Th(IV) which was tolerated up to 133 times by the addition of washing step in the manifold. The method based on single column manifold was applied on the spiked tap water, biological sample CRM (IAEA-V4) and synthetic leach liquor solution and good recovery was obtained. The method based on dual column manifold was validated on lake sediment SL-1 (CRM) and the results obtained were in good agreement at 95 % confidence level with the given value. 相似文献