Incident-angle-dependent reflectance in distributed Bragg reflectors fabricated from ZnO/MgO multilayer films

We present the incident-angle-dependent reflectance spectra of the 10-period ZnO/MgO multilayer films deposited on Si by sputtering technique. As increasing the incident angle, the resonant wavelength and bandwidth of the measured reflectance spectra exhibit redshift and narrower, respectively. The theoretical curves using transfer matrix method taken account of transverse electric (TE) and transverse magnetic (TM) polarizations are calculated to well describe the variations in the behavior of the experimental spectra. The simulated TE- and TM-reflection band at different angles can evaluate the bandwidth of the resonance band and provide valuable parameters to design an omnidirectional-reflection band in selected multilayer structure.     

What students value in effective mathematics learning: a ‘Third Wave Project’ research study

Considerations of how mathematics can be effectively taught and learnt may be cognitive, affective or sociocultural in approach. ??What students value in effective mathematics learning?? is a research study of the Third Wave Project, an international consortium of research teams adopting a sociocultural approach to investigate the harnessing of relevant values to optimise school mathematics teaching and learning. This paper seeks to contextualise the study, as part of the study examines what the high-achieving East Asian mathematics students value. The study is framed by knowledge relating to the relative cultural influence on effectiveness in mathematics learning, Alan Bishop??s values in mathematics education and the role of interactions in education, in particular David Tripp??s idea of critical incidents as reflecting professional judgement (and, thus, underlying values). Features of the innovative qualitative research design are also presented, which include the facilitation of photo-voice, the argument for an international collaborative team and focus group interviews for all values research, and a two-stage data analysis process aimed at clarifying both etic and emic perspectives.     

Synthesis,Bonding and Reactivity of a Terminal Titanium Alkylidene Hydrazido Compound

We report a detailed study of the reactions of the Ti?NNCPh₂ alkylidene hydrazide functional group in [Cp*Ti{MeC(NiPr)₂}(NNCPh₂)] ( 8 ) with a variety of unsaturated and saturated substrates. Compound 8 was prepared from [Cp*Ti{MeC(NiPr)₂}(NtBu)] and Ph₂CNNH₂. DFT calculations were used to determine the nature of the bonding for the Ti?NNCPh₂ moiety in 8 and in the previously reported [Cp₂Ti(NNCPh₂)(PMe₃)]. Reaction of 8 with CO₂ gave dimeric [(Cp*Ti{MeC(NiPr)₂}{μ‐OC(NNCPh₂)O})₂] and the “double‐insertion” dicarboxylate species [Cp*Ti‐{MeC(NiPr)₂}{OC(O)N(NCPh₂)C(O)O}] through an initial [2+2] cycloaddition product [Cp*Ti{MeC(NiPr)₂}{N(NCPh₂)C(O)O}], the congener of which could be isolated in the corresponding reaction with CS₂. The reaction with isocyanates or isothiocyanates tBuNCO or ArNCE (Ar=Tol or 2,6‐C₆H₃iPr₂; E=O, S) gave either complete NNCPh₂ transfer, [2+2] cycloaddition to Ti?N_α or single‐ or double‐substrate insertion into the Ti?N_α bond. The treatment of 8 with isonitriles RNC (R=tBu or Xyl) formed σ‐adducts [Cp*Ti{MeC(NiPr)₂}(NNCPh₂)(CNR)]. With Ar^F5CCH (Ar^F5=C₆F₅) the [2+2] cycloaddition product [Cp*Ti{MeC(NiPr)₂}{N(NCPh₂)C(Ar^F5)C(H)}] was formed, whereas with benzonitriles ArCN (Ar=Ph or Ar^F5) two equivalents of substrate were coupled in a head‐to‐tail manner across the Ti?N_α bond to form [Cp*Ti{MeC(NiPr)₂}{N(NCPh₂)C(Ar)NC(Ar)N}]. Treatment of 8 with RSiH₃ (R=aryl or Bu) or Ph₂SiH₂ gave [Cp*Ti{MeC(NiPr)₂}{N(SiHRR′)N(CHPh₂)}] (R′=H or Ph) through net 1,3‐addition of Si? H to the N? N?CPh₂ linkage of 8 , whereas reaction with PhSiH₂X (X=Cl, Br) led to the Ti?N_α 1,2‐addition products [Cp*Ti{MeC(NiPr)₂}(X){N(NCPh₂)SiH₂Ph}].     

One-pot co-precipitation of copper–manganese–zinc oxide catalysts for the oxidation of CO and SO2 in the presence of ultrasonic irradiation

Research on Chemical Intermediates - This paper studies the effect of addition of Zn and ultrasound-assisted co-precipitation on Cu-Mn oxide catalysts for the oxidation of CO. Cu-Mn-Zn oxide...     

Raman scattering from (110) Hg0.8Cd0.2Te.

We report the first polarization dependent Raman scattering from the (1$\text{1}$0) surface of Hg_0.8Cd_0.2Te. In addition to the “HgTe-like” and “CdTe-like” transverse and longitudinal $\text{(}\text{q}\text{=0)}$ optical modes, we have observed a “clustering mode” [Γ₁ symmetry], a feature due to a coupled LO phonon-intersubband excitation in the surface inversion layer and a symmetry forbidden TO feature which may be related to internal strain. The previously reported “defect mode” was not observed.     

Analysis of styrenated methyl esters of linseed oil fatty acids by molecular distillation

The distillation of the reaction product of methyl esters of linseed oil fatty acids and gaseous styrene at 280° C in a highly efficient molecular still is described. From the specific refractions of the fractions obtained it follows that styrene has combined chemically with the esters.     

What students outside Asia value in effective mathematics lessons: a scoping study

This article reports on a scoping study conducted in Australia and Sweden to facilitate the understanding of the values that are associated with effective learning of mathematics in Asian classrooms. Nineteen ??Western?? values have been identified, of which three (explanation, sharing and fun) were commonly embraced in the two countries. It is also evident that traits that are valued can be and are demonstrated in different forms. The implications for improving mathematics education through the harnessing of values are discussed. The distinction made between what is valued and the forms the value can take should empower classroom teachers to incorporate values flexibly in different classroom contexts.     

In situ determination of 238Pu in the presence of uranium by triple quadrupole ICP-MS (ICP-QQQ-MS)

Journal of Radioanalytical and Nuclear Chemistry - In this work, a direct determination of 238Pu determination using reactive gases, CO2 and H2 in triple quadrupole ICP-MS without prior...     

Synthesis and mesomorphic evaluation of new calamitic liquid crystals containing benzothiazole core

The design and synthesis of new calamitic benzothiazole-based liquid crystals,2-[4-（4-alkyloxybenzoyloxy）-phenyl]ben-zothiazoles are presented.The target compound was characterized using spectroscopic techniques,such as FT-IR,NMR(¹H and ¹³C),microanalysis and EI-MS.The liquid crystalline behaviours of these compounds were thoroughly examined by differential scanning calorimetry and polarizing optical microscope techniques.These materials exhibited enantiotropic nematic phase with high thermal stability（>168℃）.Smectic A phase starts to emerge as monotropic（metastable） phase from C10 member and changes into enantiotropic（stable） phase from C12 and persists up to C16 members.