硅油热氧化稳定剂的考察

热氧化稳定剂能显著提高硅油的热氧化稳定性。考察了乙酰丙酮铁,二茂铁,叔丁基二茂铁和二丁基二硫代氨基甲酸镍对硅油热氧化稳定性的影响。1.0‰的乙酰丙酮铁,1.0‰的二茂铁,1.0‰的叔丁基二茂铁和1.4‰的二丁基二硫代氨基甲酸镍的抗热氧化性能较好。

非硅过氧化氢稳定剂在桉木TMP浆漂白过程中的应用研究

以桉木热磨机械浆(TMP浆)为研究对象,探讨了非硅过氧化氢漂白稳定剂G1、G56替代硅酸钠用于桉木TMP浆漂白的可行性,并对漂白工艺条件进行了优化。结果表明:桉木TMP浆过氧化氢漂白采用稳定剂G1、G56替代硅酸钠是可行的。在浆浓(质量分数)20%、H2O2用量9.0%(以绝干浆质量计,下同)条件下优化的漂白工艺条件为:G1用量0.5%,G56用量0.5%,Na OH用量5.85%,温度90℃和时间30 min。在此工艺条件下桉木TMP浆单段过氧化氢漂白后,浆的白度达到77.47%(ISO),比原浆白度高38.89个百分点,比2%硅酸钠用量下漂后浆的白度高1.75个百分点,与2%硅酸钠和2%DTPA同时用作稳定剂的白度(79.88%(ISO))相当。

氧化铈复合热稳定剂

采用煅烧碳酸铈的方法制备氧化铈,将其单独用作热稳定剂,并与三碱式硫酸铅、硬脂酸钙二元或三元复配,应用刚果红法考察其对PVC热稳定性的影响。研究结果表明:单一氧化铈具有一定的热稳定作用,这主要是由于稀土可与多个氯原子配位,使PVC中的C-C l稳定,从而提高了PVC的热稳定性;氧化铈(0.67%)+硬脂酸钙(1%)+三碱式硫酸铅(0.33%)三元复配效果最好,PVC热降解温度为206℃,热稳定时间为1 450 s。

非硅酸盐过氧化氢稳定剂在制浆漂白过程中的应用

硅酸钠作为制浆漂白过程中最有效的过氧化氢稳定剂会诱发并引起一些问题,因此研发非硅酸盐过氧化氢稳定剂来取代过氧化氢漂白中的硅酸钠十分必要。本文着重从吸附屏蔽为主、络合或螯合为主以及多成分复配三种类型来阐述非硅酸盐过氧化氢稳定剂在制浆漂白过程中的应用与研究。

油脂抗氧化稳定性测试

本文简介了采用瑞士万通公司 (Metrohm)生产的 679Rancimat油脂氧化 安 定测定仪，对精炼脱臭油添加不同种类或不同含量的抗氧化剂的抗氧化效果测试，得出了 合成型抗氧化剂叔丁基对苯二酚 (TBHQ)的抗氧化效果最好；天然型油溶性茶多酚 (LOTP)抗 氧化效果较好的结论。

钇稳定氧化锆的制造方法及应用

介绍了钇稳定氧化锆的性质、用途及各种制造工艺,包括预烧结法、机械混合法、包裹沉淀法、中和共沉淀法、加水分 解法和水热法等。

提高砂基透水砖耐候性能的研究

砂基透水砖作为一种具有卓越透水性和环保特性的建筑材料,在近年来受到了广泛关注。然而,实际应用中,其耐候性能存在一定的局限,尤其是如果在长期户外暴露环境下,可能出现性能下降、劣化和褪色等问题。为了解决这一挑战,本研究通过添加二氧化钛和氧化稳定剂,旨在提高砂基透水砖的耐候性能和力学性能。系统研究了不同添加量的二氧化钛和氧化稳定剂对砂基透水砖性能的影响,寻找最佳添加量以改善耐候性和力学性能。实验结果表明,添加适度的二氧化钛有效减轻了紫外线侵害,显著增强了砖的抗压强度。同时,合理添加氧化稳定剂进一步提高了砖的耐热性和整体稳定性。通过这一研究,成功制备了一种新型的砂基透水砖,其耐候性和力学性能明显优于传统产品。这为解决砂基透水砖在户外应用中的耐候性和力学性能问题提供了有力的解决方案,也为相关领域的研究提供了重要参考。

纳米氧化锆添加量对氧化锆制品性能的影响

在电熔单斜氧化锆原料中添加不同数量的CaO稳定剂,制备部分稳定氧化锆,研究CaO加入量和稳定相数量的关系。在制备的CaO部分稳定氧化锆中添加纳米氧化锆粉体,经过造粒、200 MPa压力成型、干燥、1650℃×2 h烧成制得试样。测试试样的物理性能、分析矿物相组成、观察显微结构,研究纳米氧化锆粉体添加量对试样性能的影响。研究结果表明:2Ca-PSZ、3Ca-PSZ、4Ca-PSZ试样中,4Ca-PSZ试样稳定化程度最高;3Ca-PSZ试样显气孔率小,体积密度较大,耐压强度高。在3Ca-PSZ试样中加入纳米氧化锆粉体,随着加入量的增加,试样的显气孔率下降、烧成收缩率增加、耐压强度提高。其中纳米氧化锆粉体添加比例为8wt%时,试样气孔率为9.4%,体积密度为5.08 g/cm^3,抗压强度达到381 MPa。与3Ca-PSZ试样相比,气孔率下降40%,体积密度提高5%,耐压强度提高70%。

柴油机燃油添加剂研究发展综述

综合介绍了柴油燃料添加剂的目前研究与应用状况,并对各类添加剂作用机理的研究现状作了较为全面的阐述;同时指出柴油添加剂的今后发展方向。

Single atom gold catalysts for low-temperature CO oxidation

Low‐temperature CO oxidation is important for both fundamental studies and practical applica‐tions. Supported gold catalysts are generally regarded as the most active catalysts for low‐temperature CO oxidation. The active sites are traditionally believed to be Au nanoclusters or nanoparticles in the size range of 0.5–5 nm. Only in the last few years have single‐atom Au catalysts been proved to be active for CO oxidation. Recent advances in both experimental and theoretical studies on single‐atom Au catalysts unambiguously demonstrated that when dispersed on suitable oxide supports the Au single atoms can be extremely active for CO oxidation. In this mini‐review, recent advances in the development of Au single‐atom catalysts are discussed, with the aim of illus‐trating their unique catalytic features during CO oxidation.

Photosynthesis of Resurrection Angiosperms

Resurrection plants which are able to quickly reactivate after falling into a period of anabiosis caused by dehydration have been very rare among angiosperms, especially among dicotyledons whose chlorophyll content and chloroplast structure little changed in the course of desiccation, therefore has been called homoiochlorophyllous desiccation-tolerant plants (HDTs). Another type of resurrection angiosperms that lost its chlorophyll dining desiccation is called poikilochlorophyllous desiccation-tolerant plants (PDTs). HDTs have been received more attention because of simplicity of protection mechanism which is much easy to the study and utilization of the desiccation tolerance of resurrection angiosperms. Recent advances in studies of photosynthesis of resurrection angiosperms indicate that photochemical activities are sensitive indicators for the study of physiological state of resurrection angiosperms during desiccation and rehydration. Photochemical activities of resurrection angiosperms are inhibited with loss of water similar to those of general plants, however, the magic thing is that they could reactivate rapidly during rehydration even losing more than 95% water. Up-regulations in xanthophyll cycle and antioxidative systems as well as preservation in integrity and stability of photosynthetic membranes during desiccation may be very important to desiccation tolerance of resurrection angiosperms. The fact that phosphate treatment in rehydration stage also strongly influences resurrection indicated importance of studies on rehydration stages of resurrection angiosperms.

Flower-like 3D CuO microsphere acting as photocatalytic water oxidation catalyst

Flower-like 3D CuO microspheres were synthesized and used to photo-catalyze water oxidation under visible light.The structure of the CuO microspheres was characterized by scanning electron microscopy,transmission electron microscopy,infrared,powder X-ray diffraction,electron dispersive spectroscopy,Raman and X-ray photoelectron spectroscopy（XPS）.This is the first time that a copper oxide was demonstrated as a photocatalytic water oxidation catalyst under near neutral conditions.The catalytic activity of CuO microspheres in borate buffer shows the best performance with O2 yield of 11.5%.No change in the surface properties of CuO before and after the photocatalytic reaction was seen by XPS,which showed good catalyst stability.A photocatalytic water oxidation reaction mechanism catalyzed by the CuO microspheres was proposed.

Synthesis and characterization of colored layered double hydroxides for thermal stabilizer

Colored layered double hydroxides （LDHs） can be synthesized by introducing colored cations such as Fe^3＋ and Cr^3 ＋, which call be used as thermal stabilizers for polyvinyl chloride （PVC）. The yellowish Mg/Fe and bluish Mg/Cr LDHs are prepared by the co-precipitation method. The results show that the MgsCr_ CO3 and Mg3Fe_ CO3 colored layered double hydroxides can stabilize PVC for more than 30 min under the thermal aging temperature of 180 ℃. The preparation can use cheap Mg（OH） 2 instead of MgCl2, which produces a much smaller amount of the by-product NH4Cl. It is known that NH4Cl is a cheap fertilizer that is difficult to sell; therefore, the preparation is much greener and more economic than the one using magnesium salt.

Synthesis and application of antimony pent(isooctyl thioglycollate)

A new type of thermal stabilizer, antimony pent（isooctyl thioglycollate）(Sb(SCH2COOC8H17)5), was synthesized by using antimony trioxide, isooctanol and thioglycolic acid in 2 steps. Firstly, antimony trioxide was oxidized into colloidal antimony peroxide. Then antimony peroxide and isooctyl thioglycollate reacted stoichiometrically for 2 h with the yield of 87%. This compound was used as thermal stabilizer for polyvinyl chloride（PVC）. The results show that the thermal stability time is 52min at 200℃ by heat-ageing oven test when adding 2.5% thermal stabilizer to PVC resin. Compared with antimony tris（isooctyl thiolycollate）, the initial thermal stability of antimony pent（isooctyl thioglycollate） is better than that of antimony tris（isooctyl thioglycollate）, while the long-term thermal stability time is shorter than that of antimony tris（isooctyl thioglycollate）. Meanwhile, the synergism of antimony pent（isooctyl thioglycollate） with calcium stearate was studied, indicating that when the mass ratio of antimony pent（isooctyl thioglycollate） to calcium stearate is （2∶1,） the thermal stability time of PVC is 58min.

Study of the Stability of Beef Tallow at High Temperatures and Comparison with Other Fatty Materials

Beef tallow is a byproduct of the slaughter industry. As a consequence, meat producer countries obtain a high amount of this low value-added fatty material. In Uruguay, it is generally used for food purposes or for biodiesel production. Globally, around half of the beef tallow produced worldwide is used for the manufacturing of food. To the best of our knowledge there are no published studies concerning the stability of beef tallow when exposed to high temperatures. The aim of this work was to study some Uruguayan beef tallow brands and compare its stability with that of the most frequently used frying oils in Uruguay （sunflower high oleic, rice bran and sunflower oil） to assess its suitability for frying. Stability was assessed by the oxidative stability index and thermoxidation in absence of food. Even though beef tallow＇s inherent stability indicated that it should be highly stable to oxidation, the majority of the analyzed samples exhibited a similar or lower stability than sunflower high oleic. This might be explained by a different composition in pro-oxidants and/or antioxidants between the beef tallows and the oils. According to the thermoxidation assays, which are carried out in similar conditions to those of a frying process, three of the beef tallow samples, sunflower high oleic and rice bran oil would be similarly suitable for frying, while sunflower oil and the other two samples of beef tallow evidenced a lower thermoxidative stability, thus not being recommended for this use.

Magneli phase titanium sub-oxide conductive ceramic Ti_nO_(2n-1) as support for electrocatalyst toward oxygen reduction reaction with high activity and stability

Magneli phase titanium sub-oxide conductive ceramic Tin O2n-1 was used as the support for Pt due to its excellent resistance to electrochemical oxidation, and Pt/Tin O2n-1 composites were prepared by the impregnation-reduction method. The electrochemical stability of Tin O2n-1 was investigated and the results show almost no change in the redox region after oxidation for 20 h at 1.2 V(vs NHE) in 0.5 mol/L H2SO4 aqueous solution. The catalytic activity and stability of the Pt/Tin O2n-1 toward the oxygen reduction reaction(ORR) in 0.5 mol/L H2SO4 solution were investigated through the accelerated aging tests(AAT), and the morphology of the catalysts before and after the AAT was observed by transmission electron microscopy. At the potential of 0.55 V(vs SCE), the specific kinetic current density of the ORR on the Pt/Tin O2n-1 is about 1.5 times that of the Pt/C. The LSV curves for the Pt/C shift negatively obviously with the half-wave potential shifting about 0.02 V after 8000 cycles AAT, while no obvious change takes place for the LSV curves for the Pt/Tin O2n-1. The Pt particles supported on the carbon aggregate obviously, while the morphology of the Pt supported on Tin O2n-1 remains almost unchanged, which contributes to the electrochemical surface area loss of Pt/C being about 2times that of the Pt/Tin O2n-1. The superior catalytic stability of Pt/Tin O2n-1 toward the ORR could be attributed to the excellent stability of the Tin O2n-1 and the electronic interaction between the metals and the support.

Improving anti-sulfur performance of methane sensors by new vectors and active components

Conventional Pd/γ-A12O3 methane sensors are easily poisoned in a sulfur-containing atmosphere, with a subsequent decrease in sensitivity and the working life of methane sensors. We mainly investigated the effect of nanotechnology and a cerium co-catalyst on the stability and anti-sulfur performance of methane sensors. In our experiment, an anti-sulfur methane sensor was prepared by immersing cerium-containing γ-alumina nanometer elements into a Pt-Pd bimetallic nanometer catalyst. The experi- ment about the sensitivity and stability performance of different catalytic methane sensors indicate that sensitivity, decreased by catalyst sulfur poisoning, is improved significantly by adding cerium to the vector. As well, the long-term operational stability of methane sensors increased significantly.

Stability of isoHex-BTP/SiO_2-P adsorbent against acidic hydrolysis and γ-irradiation

Separation of trivalent minor actinides(MA(ⅡI): Am(ⅡI), Cm(ⅡI)) from fission products(FP) in high-level liquid waste(HLLW) is an important task in advanced nuclear-fuel reprocessing systems. For this purpose, an advanced aqueous partitioning process based on extraction chromatography method was studied. Because R-BTP extractants(R-BTP: 2,6-bis(5,6-dialkyl-1,2,4-triazin-3-yl)pyridine, R = alkyl group) exhibit high selectivity for MA(ⅡI) over trivalent rare-earth elements(RE(ⅡI)), a novel adsorbent isoHex-BTP/SiO2-P was prepared by impregnating isoHex-BTP extractant into the macroporous SiO2-P support with a mean diameter of 60 μm. The stability of isoHex-BTP/SiO2-P against nitric acid and γ-irradiation was investigated. It was found that isoHex-BTP/SiO2-P adsorbent shows good adsorption affinity to Dy(ⅡI). The hydrolytic and radiolytic stability of isoHex-BTP/SiO2-P adsorbent in 0.01 mol/L HNO3 was fairly promising. However, the adsorption amount Q of Dy(ⅡI) decreased dramatically in 3 mol/L HNO3 with the increase of the absorbed dose and became nearly zero at the absorbed dose over 46 kGy. These results suggest that with the synergetic effect of radiation and acidic hydrolysis, the adsorbent instantly loses its efficacy.

First-principles computational study of highly stable and active ternary PtCuNi nanocatalyst for oxygen reduction reaction

Using density functional theory （DFT） calculations, we rationally designed metallic nanocatalysts with ternary transition metals for oxygen reduction reactions （ORRs） in fuel cell applications. We surrounded binary core-shell nanoparticles with a Pt skin layer. To overcome surface segregation of the core 3-d transition metal, we identified the binary alloy Cu0.76Ni0.24 as having strongly attractive atomic interactions by computationally screening 158 different alloy configurations using energy convex hull theory. The PtskinCu0.76Ni0.24 nanoparticle showed better electrochemical stability than pure Pt nanoparticles -3 nm in size. We propose that the underlying mechanism originates from favorable compressive strain on Pt for ORR catalysis and atomic interactions among the nanoparticle shells for electrochemical stability. Our results will contribute to accurate identification and innovative design of promising nanomaterials for renewable energy systems.