Oxidative degradation of sunflower oil blended with roasted sesame oil during heating at frying temperature

The efficacy of roasted sesame oil(SO)on the oxidation deterioration of sunflower oil(SFO)during heating was investigated.The concentrations of SO in the SFO were 0,10%,20%,and 30%by volume.The oxidation profile of oil samples was monitored by evaluating the generation of oxidation products and chemical alterations in the oils'composition during heating at frying temperature(180℃).The results showed that the oxidation parameters(free fatty acid,peroxide value,p-anisidine value,total oxidation status,thiobarbituric acid value,and color index)increased significantly in SFO compared to blends or SO during thermal treatment.During heating,the concentration of polyunsaturated fatty acids(PUFA)was reduced with increased level of saturated fatty acids;these results were observed more in SFO than those of SO or blend oils.However,the presence of SO in SFO reduced the decomposition of PUFA.In Fourier-transform infrared spectroscopy,the peak intensities were significantly altered in SFO compared to the blend oils during heating.Based on the most analytical data,it may be agreed that the heating at frying temperature led to the generation of relatively higher contents of oxidative products in SFO compared to blend oils,showing a lower degree of oxidation occurred in blends.The best frying performance for the SFO was achieved by using 30%SO extracted from the roasted sesame seed.This study showed the proper blending of high polyunsaturated oil with SO can produce oil blends with high nutritional values and enhanced stability for daily cooking and deep-frying applications.

Polyvinyl acetate/poly(amide-12-b-ethylene oxide) blend membranes for carbon dioxide separation

In this paper,blend membranes from polyvinyl acetate(PVAc)and block copolymer poly(amide-12-b-ethylene oxide)(Pebax1074)are prepared by solution casting and solvent evaporation method.Although they are homogeneous on a macro-scale,the observations from DSC and SEM indicate micro-phase separation for PVAc/Pebax1074 blend membranes.With the increase of Pebax1074 content,gas permeabilities of CO2,H2,N2and CH4all increase greatly.PVAc/Pebax1074 blend membranes with high PVAc content are appropriate for CO2/CH4separation.The temperature dependence of gas permeability is divided into rubbery region and glassy region.The activation energies of permeation in rubbery region are smaller than those in glassy region,and they all decrease with increasing Pebax1074 content.For N2,H2and CH4,their gas permeation properties are mainly influenced by the dual-mode sorption and hydrostatic pressure effect.But for CO2,its permeability increases with the increase of pressure due to CO2-induced plasticization effect,which is more obvious for PVAc/Pebax1074 blend membranes with high PVAc content.

Poly(amide-6-b-ethylene oxide)/[Bmim][Tf2N] blend membranes for carbon dioxide separation

Poly（amide-6-b-ethylene oxide）（Pebax1657）/1-butyl-3-methylimidazo-lium bis[trifluoromethyl）sulfonyl]-imide（[Bmim][Tf2N]） blend membranes with different [Bmim][Tf2N] contents were prepared via solution casting and solvent evaporation method. The permeation properties of the blend membranes for CO2, N2,CH4 and H2 were studied, and the physical properties were characterized by differential scanning calorimeter（DSC） and X-ray diffraction（XRD）. Results showed that [Bmim][Tf2N] was dispersed as amorphous phase in the blend membranes, which caused the decrease of Tg（PE） and crystallinity（PA）. With the addition of [Bmim][Tf2N], the CO2 permeability increased and reached up to approximately 286 Barrer at 40 wt%[Bmim][Tf2N], which was nearly double that of pristine Pebax1657 membrane. The increase of CO2 permeability may be attributed to high intrinsic permeability of [Bmim][Tf2N], the increase of fractional free of volume（FFV） and plasticization effect. However, the CO2 permeability reduced firstly when the [Bmim][Tf2N]content was below 10 wt%, which may be due to that the small ions of [Bmim][Tf2N] in the gap of polymer chain inhibited the flexibility of polymer chain; the interaction between Pebax1657 and [Bmim][Tf2N]decreased the content of EO units available for CO2 transport and led to a more compact structure. For Pebax1657/[Bmim][Tf2N] blend membranes, the permeabilities of N2, H2 and CH4decreased with the increase of feed pressure due to the hydrostatic pressure effect, while CO2 permeability increased with the increase of feed pressure for that the CO2-induced plasticization effect was stronger than hydrostatic pressure effect.

Effect of poly(ethylene glycol) molecular weight on CO_2/N_2 separation performance of poly(amide-12-b-ethylene oxide)/poly(ethylene glycol) blend membranes

Membranes from block copolymer poly(amide-12-b-ethylene oxide)(Pebax1074) and its blends with different molecular weight poly(ethylene glycol)(PEG)(200, 400, 600, 1500, 4600 and 8000) were prepared. The thermal properties and structures of Pebax1074/PEG blend membranes were characterized by DSC and SEM, and the gas permeation properties of CO_2 and N_2 were also investigated at different temperatures. For Pebax1074/PEG blend membranes with low molecular weight PEG(MW≤ 600), higher gas permeabilities than Pebax1074 were achieved. The permeability increased with the increase of PEG molecular weight. The addition of low molecular weight PEG resulted in decrease in activation energy of permeation. For Pebax1074/PEG blend membranes with high molecular weight PEG(MW≥ 1500), due to the melt of PEO phase crystals, the gas permeation properties of blend membranes were temperaturedependent, which could be divided into crystalline region, transition region and amorphous region according to two different transition temperatures. PEG molecular weight and operation temperature determined different gas permeation properties of Pebax1074/PEG blend membranes in three regions. The activation energies of permeation in crystalline region were larger than those in amorphous region.

ULTRASONIC BEHAVIOR OF EPOXY RESINS/POLY (ETHYLENE OXIDE) BLENDS CURED WITH PHTHALIC ANHYDRIDE

By means of ultrasonic attenuation apparatus, the ultrasonic velocity and attenuation ofanhydride-cured epoxy resins (EP)/poly (ethylene oxide) (PEO) blends were measured on thebasis of pulse-echo method. It was found that the sonic velocity of the blends decreased as thetemperature increased, but attenuation coefficient increased and possessed a peak value. Largervelocity and smaller attenuation coefficient(α)can be obtained from perfect crosslinking networkstructures of pure DGEBA cured with phthalic anhydride(PA). As for cured DGEBA/PEO blendsystems,sonic velocity decreased as a function of PEO concentration,but attenuation coefficient(α) increased.

Synthesis and X-Ray Diffraction Study of All Rare-Earth Series Oxides REE_2Ti_2O_7

The pyrochlore supergroup natural minerals are the oxides for formula A2-xB2O7. In this formula, A typically is Ca, Na, TR, Ba, Fe and Mn cation. B is Ta, Ti, Nb, W, Sb. The pyrochlore supergroup is divided into five groups basis of the atomic proportions of the B-site atoms Nb, Ta, Sb, Ti, and W. They are pyrochlore, microlite, roméite, betafite, and elsmoreite, respectively. Some of these minerals containing rare-earth elements species or synthetic oxides have important applications in materials, as for optical materials, light catalyst materials, magnetoelectric materials and radioactive waste treatment etc.

High Performance Silicon Nitride-based Composite Materials with Rare-earth Oxides Additives

In the present paper,a silicon nitride-based composite processed with rare-earth oxidesadditives is presented.Its bend strength can be maintained at a value as high as 1000 MPafrom 1000 to 1370℃ and the fracture toughness measures 9-10 MPa·m1/2.The static fa-tigue behavior at 1370℃ of this material is also encouraging.Besides,two another α′/β′sialon composites doped with rare-earth oxides are also described.The effects of processingparameters on the microstructure and the properties of the materials are discussed in somedetails.

UNMIXING KINETICS AND ITS MORPHOLOGY OF POLY ( ETHYLENE OXIDE) WITH POLYETHERSULPHONES BLENDS

Unmixing kinetics in a binary polymer mixture of polyethersulphones with poly (ethylene oxide) by spinodal decomposition has been investigated with time-resolved light scattering and microscope methods. The results showed that time evolution of scattered light intensity is of an exponential growth The maximum growth rate R(qm) of phase separation has been obtained. The experimental data did not satisfy the condition that the plot of R(q)/q^2 vs q^2 should be linear For unmixing system annealing at 30℃ for three hours, its morphology manifested dish structure The experimental data of the Bragg spacing D_m can be correlated with a straight line which expresses the power-law relation, D_m=bl~α

Effect of REs(Y,Nd)addition on high temperature oxidation kinetics,oxide layer characteristic and activation energy of AZ80 alloy

The oxidation behaviors of AZ80,AZ8O-0.32 Y and AZ8O-0.38 Nd(wt.%)alloys were researched at 413℃,420℃,427v and 433℃for up to 6 h in air environment via a high precision analytical balance,a laser confocal microscope,differential scanning calorimeter(DSC)analysis,X-ray diffraction(XRD)analysis,scanning electron microscope(SEM)observation,and X-ray photoelectron spectroscopy(XPS)analysis.The results show that the weight gain and oxidation rate of AZ80 are reduced significantly,the initiation form and propagation of cracks in oxide layer are changed.Compact and protective oxide layer forms on alloy surface with Y or Nd addition.And the activation energies of AZ80,AZ80-0.32Y and AZ8O-0.38Nd alloys calculated via Arrhenius equation are 82.556 kJ/mol,177.148kJ/mol and 136.738 kJ/mol,respectively.

Experimental Research on Spontaneous Combustion Tendency of High Volatile Blended Coals

Experiment of oxidation characteristics with slow velocity of high volatile blended coals was investigated in the surroundings of low oxygen conditions, which gives three kinetic factors in the step of low temperature through the methods of thermo gravimetric analysis, the Coats-Redfern integration and Achar-Brindley-Sharp-Wendworth. The results of calculation show that activation energy and pre-exponential factor increase with the reaction process, and tendency of spontaneous combustion of the blended coal have changed. The experimental results show that the type of absorbing oxygen is mainly physical adsorption and calorific value is very small during increasing weight. Volatile of blended coal releases before single coal and combustion temperature of blended coal is between one and other single coals. If the oxygen content is below 16% in the milling system, explosion-proof effect on high volatile blended coal can be obtained.

“虚拟仿真+试误教学法”实验教学模式的探索与实践

以虚拟仿真结合“试误”教学法,建立混合式实验教学模式用于药学专业高危类化学实验教学。以氧化石墨烯的制备为例,采用3D MAX、IdeaVR等软件对实验场景、仪器设备等进行高度仿真。在线教学模式便于学生随时随地沉浸式学习,凸显“以学生为本”的教育理念;增加“试误”选项,让学生体验错误操作会导致爆炸等危险后果,强化关键知识点。基于“试误”教学法的虚拟仿真实验模式,不仅解决了传统实验教学中安全隐患大、污染严重等问题,能够以虚补实,而且为学生创造了自主性高、探索式学习环境,同时,该教学模式为危险系数高的化学类实验课程的开设提供了教学示范。

改善预热球团矿抗压强度的工艺优化

为了改善预热球团矿的抗压强度,结合生产实践经验,模拟链篦机-回转窑工艺制度,采用正交实验法分析了影响预热球团矿抗压强度的因素及工艺改进措施。结果表明,OA矿和OB矿粒度较细,-0.074 mm粒级含量大于85%,能满足造球粒度基本要求;90%OA矿搭配10%OB矿时,经过干燥、预热工艺段,球团矿FeO含量可以从26%降低到4%以下,氧化度大于85%;提高预热球团矿抗压强度的适宜链篦机热工参数为:鼓风干燥温度200℃、抽风干燥温度360℃、预热Ⅰ段温度720℃、预热Ⅱ段温度990℃,此条件下预热球团矿抗压强度可达1056 N/球;验证实验符合预期结果。

燃煤耦合农林废弃物在流化床内燃烧的氮氧化物生成特性模拟研究

通过化学反应动力学模拟方法构建了流化床燃烧反应模型,研究了燃煤耦合农林废弃物燃烧过程中氮氧化物的生成特性与反应机理。结果表明:氮氧化物转化率随着农林废弃物掺混比例增加而增大,且随着生物质掺入量增加,转化率增长速率提高;燃烧温度对氮氧化物转化率的影响较大;随着燃烧系统氧体积分数增大,氮氧化物转化率先缓慢增大,在氧体积分数达到一定值后迅速增大,之后变化趋于缓慢;出于经济性与技术可行性的考量,可以选择降低风量小的燃尽风氧体积分数来进一步降低氮氧化物生成量,为实际燃煤耦合生物质燃烧锅炉控制污染物排放提供一定的技术支撑和指导意见。

熔喷非织造布用磁性Fe_(3)O_(4)@SiO_(2)/PLA共混材料的性能分析

采用溶剂热法制备磁性四氧化三铁(Fe_(3)O_(4))纳米粒子,随后利用改进的溶胶-凝胶法制备四氧化三铁与二氧化硅复合纳米粒子(Fe_(3)O_(4)@SiO_(2)),再以聚乳酸(PLA)为基体,通过熔融共混工艺制备Fe_(3)O_(4)@SiO_(2)/PLA共混材料。采用扫描电子显微镜(SEM)、X射线衍射仪(XRD)、差示扫描量热仪(DSC)、万能拉伸试验机、熔体流动速率仪(MFR)和振动样品磁强计(VSM)等对共混材料的形貌、结晶结构、热性能、力学性能、熔体流动速率和磁性能进行表征分析。结果表明:添加量为1%(以质量分数计)的Fe_(3)O_(4)@SiO_(2)纳米粒子可在PLA基体中均匀分散,与基体有良好的界面相容性。相比于纯PLA,Fe_(3)O_(4)@SiO_(2)/PLA共混材料的热性能变化不大,当Fe_(3)O_(4)@SiO_(2)的添加量为1%时,共混材料的结晶度最大。随着Fe_(3)O_(4)@SiO_(2)质量分数的增加,共混材料的拉伸强度呈先增加后下降的趋势,而断裂伸长率没有明显变化。在同一温度下,Fe_(3)O_(4)@SiO_(2)/PLA共混材料的熔体流动速率明显增加,熔融指数大于150 g/(10 min),流动性较好,能满足熔喷加工可纺性的要求。另外,Fe_(3)O_(4)@SiO_(2)/PLA共混材料的饱和磁化强度会随着Fe_(3)O_(4)@SiO_(2)质量分数的增加逐渐增加。研究结果可为开发熔喷非织造布用磁性Fe_(3)O_(4)@SiO_(2)/PLA共混材料提供理论依据。

Temperature-sensing array using the metal-to-insulator transition of Nd_(x)Sm_(1-x)NiO_(3)

Rare-earth nickelates(RENiO_(3))show widely tunable metal-to-insulator transition(MIT)properties with ignorable variations in lattice constants and small latent heat across the critical temperature(TMIT).Particularly,it is worth noting that compared with the more commonly investigated vanadium oxides,the MIT of RENiO_(3)is less abrupt but usually across a wider range of temperatures.This sheds light on their alternative applications as negative temperature coefficient resistance(NTCR)thermistors with high sensitivity compared with the current NTCR thermistors,other than their expected use as critical temperature resistance thermistors.In this work,we demonstrate the NTCR thermistor functionality for using the adjustable MIT of Nd_(x)Sm_(1-x)NiO_(3)within 200–400 K,which displays larger magnitudes of NTCR(e.g.,more than 7%/K)that is unattainable in traditional NTCR thermistor materials.The temperature dependence of resistance(R–T)shows sharp variation during the MIT of Nd_(x)Sm_(1-x)NiO_(3)with no hysteresis via decreasing the Nd content(e.g.,x≤0.8),and such a R–T tendency can be linearized by introducing an optimum parallel resistor.The sensitive range of temperature can be further extended to 210–360 K by combining a series of Nd_(x)Sm_(1-x)NiO_(3)with eight rare-earth co-occupation ratios as an array,with a high magnitude of NTCR(e.g.,7%–14%/K)covering the entire range of temperatures.

以掺氢天然气为燃料直接内重整固体氧化物电池堆的稳定性

本文研究了掺氢天然气直接内重整平管型固体氧化物电池短堆的长期稳定性和衰减机理。通过约3000小时的实测实验,结果显示,电堆的总体衰减率为2.3%·kh^(-1),电堆中三个金属连接板的面积比电阻分别增加了0.276Ω·cm^(2)、0.254Ω·cm^(2)和0.249Ω·cm^(2),但电堆中两个电池的电压反而分别增加了3.38 m V·kh^(-1)和3.78 m V·kh^(-1)。电堆衰减主要由金属连接件表层氧化及其与阴极集流层材料反应生成Sr CrO_(4)物质,两者共同作用增大了电池与金属连接体间的界面电阻所致。结果表明,以掺氢天然气为燃料直接内重整平管型固体氧化物燃料电池电堆具有良好的稳定性。本文工作为掺氢天然气在固体氧化物燃料电池堆中的直接内重整应用提供了理论参考与实验依据。

喷气涡流纺汉麻混纺纱及面料的生产

为了开发色织大提花喷气涡流纺细号高混比汉麻纱及其面料,详细分析以渗透剂改善纤维回潮率,以氧化剂降低木质素含量,提升汉麻纤维可纺性及舒适性的原理及方法;以多组分混纺、使用特殊油剂,提升涡流纺纱线柔软度以及纱线强力的具体工艺;在纱线表面被覆柔软剂增加经纱柔韧性,在开口区给湿增加经向股线韧性来提升汉麻混纺纱可织性的方法。通过测试汉麻混纺纱的成纱质量和面料质量,表明:选取15%平平加O渗透剂和0.05 L/kg~0.50 L/kg的臭氧用量对汉麻纤维进行养生处理,使用白油作为润滑剂、二甲基硅油作为防粘剂,纺制的汉麻30/粘胶30/棉40 MVS 14.7 tex混纺纱可批量生产且质量稳定;采用MVS 14.7 tex混纺纱合股、在织机开口区给湿结合经纱柔软剂被覆处理技术后,该汉麻混纺纱面料织造效率高、抗菌性优良;今后应进一步加大细号高混比汉麻混纺纱工艺研究,完善织口加湿技术。

煤岩学方法在异常炼焦煤煤质评价中的应用

通过煤岩学方法中的反射率分布和煤岩显微组分可反映煤质特性,但随着炼焦煤资源日益劣化,需利用煤岩学方法判断炼焦异常煤,并对异常炼焦煤的质量进行评价。通过煤岩反射率自动测试系统对炼焦煤资源进行分析,结合煤岩反射率分布并根据商品煤的煤岩判定标准,在炼焦配煤实际应用中判断是否为同类炼焦煤混煤、混入低品质炼焦煤的混煤或混入非炼焦煤的混煤,并从煤氧化的判定、混入兰炭或工业废渣等方面探讨由煤岩显微组分判定异常煤。研究表明:煤岩反射率主要应用于判定混煤,应区别对待同类混煤、混入低质炼焦煤和混入非炼焦煤该3类混煤,尤其需避免混入非炼焦煤;煤岩显微组分是对煤岩反射率自动测定系统的补充,通过煤岩观察显微组分,可以判断炼焦煤的氧化、混入兰炭及混入工业废渣等是炼焦煤异常的主要原因;煤岩学方法是判定炼焦煤异常的主要技术手段,但煤岩指标仅对传统指标有补充作用而非完全替代作用。

Spectroscopic Investigation and Characterizations of PAM/PEO Blends Films

Polymer blends have been obtained in the form of dimensionally stable and free standing films and their properties were characterized by different techniques. FTIR analysis and Raman spectroscopic analysis cleared the hydrogen bonding intermolecular interaction between –CONH2 groups in Poly Acrylamide (PAM) and C-O-C and –CH2OH group in Poly Ethylene Oxide (PEO). From Differential Scanning Calorimeter (DSC) the study shows that crystallinity is increasing with PEO wt%. From polymer interaction parameter we also show that the polymer blend is miscible. Thermal stability of films is investigated by Thermo Gravimetric Analysis (TGA) and derivative Thermo Gravimetric Analysis (DrTG). From UV-Vis absorption spectra, absorption band edge, direct/ indirect band gap and optical activation energy have been calculated.

STUDIES ON THE COMPATIBILITY OF PPO MULTI-COMPONENT BLENDS

The compatibility and phase morphology of poly (phenylcne oxide) (PPO) multi-componenet blends with poly (ethylene terephthalate) (PET) and polystyrene (PS) were studied using differentialscanning calorimetry (DSC), dynamic mechanical analysis (DMA) and scanning electron microsopy (SEM) methods. The effect of glycidyl methacrylate-styrene copolymer (GMS), as a compatibilizer, on the morphology of the PPO blends has also been studied in detail. The influence of the moiecular weight of PET and the synergetic effect of the compatibilizers of GMS and phenoxy on the morphology were examined. The DSC and DMA results show that there are two distinct glass transitions correspondinig to PET and PPO existed, however, the Tg of PPO shifts toward lower temperature region due to the addition of GMS and PS. The SEM results reveal that PET component is as dispersed phases in the PPO matrix, part of which is located at the interfaces due to the interaction with GMS while PS is miscible in the PPO matrix. A