Publications by authors named "Yee Lok Wong"

The use of visual representations of time is common in both research and daily life, with progress icons, such as bars and rings, being popular examples. Despite some studies investigating the advantage of different shapes, there has been no consistent result from questionnaires. This study aims to investigate this topic by using an objective temporal reproduction task to compare the potential difference between short and long waiting times, as evidence indicates that the temporal machinery could be different within and beyond 2-3 s.

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This paper presents the certification of alpha-endosulfan, beta-endosulfan, and endosulfan sulfate in a candidate tea certified reference material (code: GLHK-11-03) according to the requirements of the ISO Guide 30 series. Certification of GLHK-11-03 was based on an analytical method purposely developed for the accurate measurement of the mass fraction of the target analytes in the material. An isotope dilution mass spectrometry (IDMS) method involving determination by (i) gas chromatography-negative chemical ionization-mass spectrometry (GC-NCI-MS) and (ii) gas chromatography-electron ionization-high-resolution mass spectrometry (GC-EI-HRMS) techniques was employed.

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This paper presents the preparation of a candidate certified reference material (CRM) of cypermethrin in green tea, GLHK-11-01a according to the requirements of ISO Guide 34 and 35. Certification of the material was performed using a newly developed isotope dilution mass spectrometry (IDMS) approach, with gas chromatography high resolution mass spectrometry (GC-HRMS) and gas chromatography-tandem mass spectrometry (GC-MS/MS). Statistical analysis (one-way ANOVA) showed excellent agreement of the analytical data sets generated from the two mass spectrometric detections.

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A series of N₂O₂ tripodal tetradentate ligands derived from di-/tetra-tert-butyl substituted 2-[bis(2-hydroxybenzyl)aminomethyl]X (X = pyridine and benzimidazole) (H₂L(n) (n = 1-4)) and 8-[bis(3,5-di-tert-butyl-2-hydroxybenzyl)]aminoquinoline (H₂L⁵) were synthesised through a 4-step reaction scheme involving sequential formylation, reduction, bromination and alkylation. Treatment of H₂L(n) (n = 1-5) with [WO₂Cl₂(dme)] (dme = 1,2-dimethoxyethane) in the presence of triethylamine gave the corresponding cis-dioxotungsten(VI) complexes [WO₂(L(n))] (n = 1-5). The corresponding molybdenum analogues [MoO₂(L(n))] (n = 1-5) were also prepared from the reaction of [MoO₂(acac)₂] (acac = acetylacetonate) with H₂L(n) (n = 1-3) or [MoO₂Cl₂(dme)] (dme = 1,2-dimethoxyethane) with H₂L(n) (n = 4 and 5).

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A new family of N-capped tripodal NO(3) proligands N,N-bis(2-hydroxy-3,5-di-tert-butylbenzyl)-N-(2'-hydroxy-5'-R-phenyl)amine [H(3)(L(n))] [when R= Me, n = 1; R= (t)Bu, n = 2; R = Cl, n = 3] with different substituents in one of the aryl rings and N,N-bis(2-hydroxy-3-tert-butylbenzyl)-N-(2'-hydroxy-5'-methylphenyl)amine [H(3)(L(4))] were synthesised. The preparation of a new pentadentate proligand N-methyl-N,N',N'-tris(2-hydroxy-3,5-di-tert-butylbenzyl)ethane-1,2-diamine [H(3)(L(5))] with an N(2)O(3) donor set is also reported. Reaction of the proligands [H(3)(L(n))] (n = 1-4) with iron(III) chloride in the presence of base (triethylamine) and 1-methylimidazole (1-Meim) as co-ligand led to the formation of iron complexes of the type [Fe(L(n))(1-Meim)] (n = 1-4) (1-4) respectively, while treatment of the trilithium salt of [H(3)(L(5))] with iron(III) chloride afforded [Fe(L(5))] (5).

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A new series of cis-dioxomolybdenum(VI) complexes MoO(2)(L(n))Cl (n = 1-5) were prepared by the reaction of MoO(2)Cl(2)(DME) (DME = 1,2-dimethoxyethane) with 2-N-(2-pyridylmethyl)aminophenol (HL(1)) or its N-alkyl derivatives (HL(n)) (n = 2-5) in the presence of triethylamine. The new mu-oxo dimolybdenum compounds [MoO(2)(L(n))](2)O (n = 1, 4, 5, 7) were also prepared by treating the corresponding ligand HL(n) with MoO(2)(acac)(2) (acac = acetylacetonate) in warm methanolic solutions or (NH(4))(6)[Mo(7)O(24)].4H(2)O in the presence of dilute HCl.

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