Recyclable MoO3 nanobelts for photocatalytic degradation of Rhodamine B by near infrared irradiation

Molybdenum trioxide (MoO₃) represented an excellent photocatalytic performance with many applications, including degradation of organic contaminants and splitting of water. This paper presented a new route to synthesize MoO₃ nanobelts with high aspect ratios and crystallinity by a hydrothermal technique. This work showed that the as-synthesized nanobelts exhibited strong photocatalytic activity to degrade an organic dye of Rhodamine B (RhB) in aqueous solution under the exposure of the light source in the near infrared wavelength range, significantly improving the photocatalytic activity of the nanobelts. The results also showed that for a small concentration of RhB at 7.5 mg/L a complete photodegradation (for a given MoO₃ nanobelts quantity of 0.1 g) can be reached after exposing for 60 min. For all concentrations of the RhB solution, the photodegradation exhibited an exponential dependence on the exposure time followed by a sudden shutdown, but no complete photodegradation can be reached. Also, the residual quantity of RhB in solution after the photocatalytic reaction was determined by the initial RhB concentration. The photocatalytic degradation can be interpreted by the pseudo–first-order equation for the absorption of liquid/solid based on solid capacity; thus, photocatalytic degradation can be attributed to the interaction between the photoexcited electrons in the substrate and the antibonding orbital of the RhB in solution. The sudden shutdown was due to the inability of the photoexcited electrons in the substrate hopping to the antibonding orbital of RhB in the presence of the RhB intermediate products from the degraded RhB. In addition, this work showed that the photocatalytic reaction can be recovered after a thermal treatment of postreacted MoO₃ nanobelts, enhancing the utilization efficiency of the catalysis.     

An investigation of Forex market efficiency based on detrended fluctuation analysis: A case study for Iran

The efficient market hypothesis (EMH) states that asset prices fully reflect all available information. As a result, speculators cannot predict the future behavior of asset prices and earn excess profits at least after adjusting for risk. Although initial tests of the EMH were performed on stock market data, the EMH was soon applied to other markets including foreign exchange (FX). This study uses the detrended fluctuation analysis (DFA) technique to test 01:12:2005–18:04:2010 Iranian Rial/US Dollar exchange rate time series data to see if it can be explained by the weak form of the EMH. Moreover, to determine changes in the degree of inefficiency over time, the whole period has been divided into four subperiods. The study shows that the Iranian Forex market (the Rial/Dollar case) is weak-form inefficient over the whole period and in each of the subperiods. However, the degree of inefficiency is not constant over time. The findings suggest that profitable risk-adjusted trades could be made using past data.     

Muon g-2 discrepancy:new physics or a relatively light Higgs?

After a brief review of the muon g-2 status,we discuss hypothetical errors in the Standard Model prediction that might explain the present discrepancy with the experimental value.None of them seems likely.In particular,a hypothetical increase of the hadroproduction cross section in low-energy e+e-collisions could bridge the muon g-2 discrepancy,but it is shown to be unlikely in view of current experimental error estimates.If,nonetheless,this turns out to be the explanation of the discrepancy,then the 95% CL upper bound on the Higgs boson mass is reduced to about 135 GeV which,in conjunction with the experimental 114.4 GeV 95%CL lower bound,leaves a narrow window for the mass of this fundamental particle.     

Eulerian spatial and temporal autocorrelations: assessment of Taylor's hypothesis and a model

We present measurements of Eulerian longitudinal velocity autocorrelations in homogeneous, isotropic, high-intensity (～9%) free-stream turbulence behind an active grid. Spatial correlations are measured using particle image velocimetry as well as with two-point hot-wire anemometry (HWA), while temporal correlations are measured using HWA. The temporal correlations are transformed into spatial correlations by using Taylor's ‘frozen’ hypothesis with both the mean as well as instantaneous velocities. A model relating Eulerian spatial and temporal autocorrelations is also used for this purpose. The differences from the measured spatial correlation resulting from the use of Taylor's hypothesis on the temporal correlation is quantified; even at this moderately high level of turbulent intensity, the result from the use of the instantaneous velocity as convection velocity is practically indistinguishable from that obtained using the mean velocity. Use of the model produces a good agreement between the estimates of the spatial correlation function. A relation between Eulerian spatial and temporal integral scales is also derived.     

Urea and thiourea derivatives of 3-(trifluoromethyl)-5,6,7,8-tetrahydro-[1, 2, 4]triazolo[4,3-a]pyrazine: Synthesis,characterization, antimicrobial activity and docking studies

Abstract

An efficient and robust synthetic procedure was developed primarily for the synthesis of a precursor compound; 3-(trifluoromethyl)-5,6,7,8-tetrahydro-[1, 2, 4]triazolo[4,3-a]pyrazine (11), from 2-chloropyrazine (7) through the chemical transformations such as hydrazine substitution, trifluoroacetyl group induction, cyclization and pyrazine ring reduction. A new series of urea derivatives 13a-e and thiourea derivatives 13f-j of compound 11 have been synthesized and the structures of all the compounds were confirmed using spectroscopic analyses such as IR, ¹H NMR, ¹³C NMR, LC-MS and HRMS. The newly synthesized compounds were screened for their in vitro antimicrobial activity against five bacteria and two fungi, in which compounds 13d, 13i and 13j displayed potential activity against bacterial strains and 13a, 13d, 13g and 13j against fungal strains with the MIC values in the range of 6.25–25.0 µg/mL. An overall comparison of the activity results revealed that thiourea derivatives contain better activity than that of urea compounds. Molecular docking studies on poly (ADP-ribose) polymerase 15 (ARTD7, BAL3) demonstrated that all the synthesized compounds possess significant binding energies (-8.1 to -9.8?kcal/mol) with no adverse effect in the active site of protein.     

钴掺杂Sr1.5La0.5MnO4的合成及高温电化学性能研究

采用EDTA-柠檬酸法合成了中温固体氧化物燃料电池阴极材料Sr_1.5La_0.5Mn_1-xCo_xO₄（SLMCO_x）,并利用粉末X射线衍射（XRD）、X射线光电子能谱（XPS）以及电化学交流阻抗谱（EIS）进行表征。结果表明,该材料与Ce_0.9Gd_0.1O_1.95（CGO）在1 200℃烧结12 h不发生化学反应。随着Co掺入量的增加,氧化物中Mn³⁺和Co²⁺含量增多,晶格氧含量降低,晶格畸变率增大。交流阻抗谱（EIS）测试结果显示,钴的掺杂明显降低电极的极化电阻,其中Sr_1.5La_0.5Mn_0.7Co_0.3O₄阴极在700℃空气中的极化电阻为0.62 Ω·cm²,明显小于Sr_1.5La_0.5MnO₄阴极在750℃的极化电阻（1.5 Ω·cm²）,表明钴掺杂的Sr_1.5La_0.5Mn_1-xCo_xO₄是一种潜在的IT-SOFC阴极材料。     

(Pr0.9La0.1)2(Ni0.74Cu0.21Ga0.05)O4+δ-Ce0.9Gd0.1O2-δ复合阴极的制备及电化学性质

采用EDTA-柠檬酸盐法制备了（Pr_0.9La_0.1）₂（Ni_0.74Cu_0.21Ga_0.05）O_4+δ（PLNCG）,并与Ce_0.9Gd_0.1O_2-δ（CGO）形成复合阴极PLNCG-CGO。XRD和SEM分析结果表明PLNCG与CGO在1 000℃具有较好的化学相容性。电化学阻抗测试结果表明PLNCG-30% CGO复合阴极在700℃的极化电阻为0.092 Ω·cm²;过电位为39.3 mV时,电流密度达到113.3 mA·cm^-2。氧分压分析表明电极反应的速率控制步骤为电荷转移过程。阳极支撑单电池（Ni-CGO/CGO/PLNCG-30% CGO）在700℃的最大输出功率密度达到569 mW·cm^-2,开路电压（OCV）为0.76 V。综上结果预示PLNCG-30% CGO复合阴极是一种有发展前景的电极材料。     

二丙胺的结构微调对磷酸铝分子筛晶化过程影响的凝胶组成依赖性

以二丙胺异构体（二正丙胺DPA和二异丙胺D-iPA）为结构导向剂,在200℃加热2组反应原料物质的量之比不同的初始凝胶,合成出了高结晶度的磷酸铝分子筛AlPO₄-11。利用X射线粉末衍射分析、元素分析等表征手段,研究了凝胶的晶化过程和液相的pH值以及Al和P的浓度演化。初始凝胶各组分物质的量之比为n_Al2O3：n_P2O5：n_DPA/D-iPA：n_H2O2=1.0：1.0：1.2：75时,以DPA为结构导向剂,晶化过程中无中间相生成,而以D-iPA为结构导向剂时,晶化过程中生成了具有12元环孔道结构的磷酸铝分子筛AlPO₄-5中间相;初始凝胶各组分物质的量之比为n_Al2O3：n_P2O5：n_DPA/D-iPA：n_H2O2=1.0：1.0：1.0：75时,以DPA为结构导向剂,晶化过程中生成了具有18元环孔道结构的磷酸铝分子筛VPI-5中间相,而以D-iPA为结构导向剂时,晶化过程中同时出现了VPI-5及AlPO₄-5两种中间相。表明对于同一种有机胺,凝胶物质的量之比的改变影响了其结构导向效应。理论计算结果显示质子化的DPA及D-iPA中N原子上的电荷有差异,表明有机胺的结构微调影响其结构导向效应,但该影响依赖于凝胶组成。     

中温固体氧化物燃料电池阴极材料LaBiMn2O6的制备与性能研究

采用固相法合成了中温固体氧化物燃料电池(IT-SOFCs)阴极材料LaBiMn₂O₆,并利用X射线衍射(XRD)和电化学阻抗谱(EIS)进行表征.结果表明该材料与电解质Ce_0.7Bi_0.3O_1.85(CBO)在1 000 ℃烧结12 h不发生反应.交流阻抗和直流极化测试结果发现,阴极极化电阻随测试温度的增加而逐渐减小,700 ℃空气中的极化电阻为0.71 Ω·cm²;氧分压测试结果显示,在600~700 ℃范围内,电极反应的速率控制步骤为电极上发生的电荷转移反应.电极过电位为85 mV时,700 ℃的阴极电流密度达到 216 mA·cm^-2 ,表明LaBiMn₂O₆是一种潜在的中温固体氧化物燃料电池(IT-SOFCs)阴极材料.     

Mild method for the synthesis of 1H-indazoles through oxime-phosphonium ion intermediate

The synthesis of 1H-indazoles from o-aminobenzoximes is achieved via N–N bond formation using triphenylphosphine, I₂, and imidazole. Selective formation of oxime-phosphonium ion intermediate in the presence of the amino group is the driving force for this reaction. The nucleophilicity of the arylamino group and electrophilicity toward the N–O bond of oxime also control the reaction. The reaction proceeds at a faster rate with good to excellent yield under this mild reaction condition and is amenable to scale-up.