Solubility and Thermal Degradation of Quercetin in CO2-Expanded Liquids

The solubility of quercetin and its thermal degradation was studied in CO₂-expanded ethanol and ethyl lactate. An equipment setup was constructed that enabled the separation of the products of degradation while quantifying the solubility of quercetin. Three different conditions of temperature were analyzed (308, 323, and 343 K) at 10 MPa. Higher solubility and thermal degradation of quercetin were observed for CO₂-expanded ethyl lactate in comparison with CO₂-expanded ethanol. At the same time, as the amount of CO₂ was increased in the CO₂-expanded liquids mixtures, the thermal degradation of quercetin decreased for almost all the conditions of temperature considered in this work. The importance of considering thermal degradation while performing solubility measurements of compounds that are thermally unstable such as quercetin was highlighted.     

An unexpected generation of magnetically separable Se/Fe3O4 for catalytic degradation of polyene contaminants with molecular oxygen

Selenization of Fe₂O₃ with NaHSe led to Se/Fe₃O₄. The unexpected generation of Fe₃O₄ attributed to the reduction conditions of the reaction, and the resulted magnetic features of the material facilitated its separation in practical applications. Owning to the synergistic effect of Se with Fe, the material was especially active to catalyze the oxidative C=C scission using O₂ as mild oxidant. The technique has been successfully applied in polyene degradation project, which is of profound practical values for the treatment of the polyene pigment pollution and may be applied in the food and pharmaceutical industry.     

Green synthesis of silver nanoparticles using Eucalyptus comadulensis leaves extract and its immobilization on magnetic nanocomposite (GO-Fe3O4/PAA/Ag) as a recoverable catalyst for degradation of organic dyes in water

The magnetically recyclable graphene oxide-Fe₃O₄/polyallylamine (PAA)/Ag nanocatalyst was prepared via a green route using Eucalyptus comadulensis leaves extract as both reducing and stabilizing agent. The catalytic activity of this nanocatalyst was investigated for the reduction reaction of methylene blue and methyl orange in the presence of NaBH₄ in aqueous medium at room temperature. The prepared nanocatalyst was characterized by different methods such as Fourier transformed infrared spectroscopy, X-ray diffraction, scanning electron microscopy–energy dispersive X–ray spectroscopy, thermogravimetric analysis, vibrating sample magnetometer, transmission electron microscopy, and UV–visible spectroscopy. The results show that graphene oxide/PAA/Ag nanocatalyst has good activity and recyclability, and can be reused several times without major loss of activity in the reduction process. The apparent rate constants of the methyl orange (MO) and methylene blue (MB) were calculated to be 0.077 s⁻¹ (3 mg of catalyst) and 0.15 s⁻¹ (2 mg of catalyst), respectively.     

Solar Light Photocatalytic Degradation of Malachite Green by Hydrothermally Synthesized Strontium Arsenate Nanomaterial through Response Surface Methodology

Nanostructured Sr₂As₂O₇ samples were synthesized by hydrothermal crystal growth reactions between Sr(NO₃)₂ and As₂O₃ with different stoichiometric Sr:As molar ratios as 1:1 (S₁), 1:2 (S₂), and 2:1 (S₃). The synthesized nanomaterials were characterized by powder X‐ray diffraction (PXRD) technique and fourier‐transform infrared (FT‐IR) spectroscopy. Rietveld analysis showed that the obtained materials were crystallized well in the monoclinic crystal structure with the space group P2₁. The morphologies of the synthesized materials were studied by field emission scanning electron microscopy (FESEM) technique. TEM images verified formation of the particles with nanometer size. Ultraviolet‐visible spectra analysis showed that the synthesized Sr₂As₂O₇ nanomaterials had strong light absorption in the ultraviolet light region. Photocatalytic performance of the synthesized nanomaterials was also investigated for the degradation of pollutant Malachite Green (4‐{[4‐(dimethylamino)phenyl](phenyl)methylidene}‐N′N‐dimethylcyclohexa‐25‐dien‐1‐iminium chloride) (MG) in aqueous solution under solar light condition. The optimal conditions were obtained by design expert software for S₁. It was found that the optimum condition was 0.14 mL H₂O₂, 20 mg catalyst, and 33 min time. The volume and concentration of the as prepared MG solution were 70 mL and 100 ppm, respectively, for obtaining the optimum conditions. The degradation yield in the optimized conditions was 97 % for S₁.     

基于苯四酸和双咪唑甲基苯构筑的Co(Ⅱ)和Ni(Ⅱ)配合物的合成、晶体结构及光催化活性

在水热条件下，得到了2例新的配位聚合物[Co(L)_0.5(1，3-bib)] (1)和[Ni₂(L)(1，4-bib)₃(H₂O)₂]·2H₂O (2)，其中L=1，2，4，5-苯四酸，1，3-bib=1，3-双((1H-咪唑1-基)甲基)苯，1，4-bib=1，4-双((1H-咪唑1-基)甲基)苯。并利用元素分析、红外光谱、单晶X射线衍射等对其进行了结构表征。结果表明：1和2均为三维网状结构，完全去质子化的配体(L^4-)在1和2中分别采取了μ₄-к²∶к¹∶к²∶к¹和μ₂-к¹∶к⁰∶к¹∶к⁰的配位方式。进一步的研究表明，配合物1在H₂O₂和可见光照射的条件下，在水溶液中对染料甲基橙(MO)和亚甲蓝(MB)有很好的降解效果：在180 min时，降解率分别达到83.2%和84.5%。配合物2在同样的条件下，在水溶液中对染料MB和罗丹明B(RhB)也有较好的降解作用：在180 min时，降解率分别为87.0%和77.4%。此外还详细探讨了1和2对染料光催化降解的机理。     

Viewing angle controllable fringe and in-plane switching vertical alignment LCD

A viewing angle controllable fringe and in-plane switching vertical alignment liquid crystal display (LCD) structure has been proposed. To realise the change from wide viewing angle (WVA) to narrow viewing angle (NVA) in a single LCD panel, the bias voltage is applied on the common electrode, and NVA can decreases with the increasing bias voltage. In WVA mode, the viewing angle cone (contrast ratio larger than 1000:1) is almost 70° and the contrast ratio is larger than 100:1 in arbitrary azimuthal directions. In NVA mode, the viewing angle cone (10:1) can continuously and uniformly change from 40° to 20°.     

Thermal decomposition of microbial poly(γ-glutamic acid) and poly(γ-glutamate)s

The thermal decomposition of poly(γ-glutamic acid), poly(α-methyl γ-glutamate) and ionic complexes of the polyacid with alkyltrimethyl ammonium salts was studied by TGA, GPC, and FTIR and NMR spectroscopies. It was found that both poly(γ-glutamic acid) and poly(α-methyl γ-glutamate) depolymerised above 200 °C by unzipping mechanism with generation of pyroglutamic acid and methyl pyroglutamate, respectively. On the other hand, the ionic complexes degraded through a two-stage process, the first stage being cyclodepolymerisation of the poly(γ-glutamate) main chain along with decomposition of the ionic complex promoted by the adsorbed water. Decomposition of the previously generated alkyltrimethyl ammonium compound followed by unspecific cracking of the resulting nitrogenated compounds accounted for the second degradation step, at higher temperatures. Mechanisms explaining the decomposition of the three studied systems were proposed according to collected data.     

Fuel cell catalyst degradation on the nanoscale

A newly developed methodology for examining fuel cell catalyst degradation is introduced. In contrast to the conventional, destructive TEM investigation procedure, this methodology enables the observation of corrosion processes of the same catalyst region repeatedly. In particular we demonstrate the impact of a potential cycling treatment on a carbon-supported platinum catalyst, and propose a new corrosion mechanism for fuel cell catalyst degradation. Under the applied harsh conditions, whole Pt particles detach from the support and dissolve into the electrolyte without re-deposition.     

The method of p-harmonic approximation and optimal interior partial regularity for energy minimizing p-harmonic maps under the controllable growth condition

In this paper, we are concerned with the partial regularity for the weak solutions of energy minimizing p-harmonic maps under the controllable growth condition. We get the interior partial regularity by the p-harmonic approximation method together with the technique used to get the decay estimation on some Degenerate elliptic equations and the obstacle problem by Tan and Yan. In particular, we directly get the optimal regularity.