Investigation of Microstructure and Phase Composition of Chromic Oxide, AZS/Cr and High-alumina Refractories after Exposure of Basalt and Aluminaboronsilicate Glasses Melts

The microstructure and phase composition of high-alumina,chromic oxide,and AZS/Cr refractories containing 30%and 60%(by mass)Cr_(2)O_(3) after exposure to aluminaboronsilicate glasses and basalt melts depending on the type of melts and temperature have been studied.The mechanisms of refractory corrosion by the used melts and the factors contributing to the inhibition of corrosion development have been investigated by the method of petrographic analysis.On the basis of obtained results,the use of high-alumina,chromic oxide,and AZS/Cr refractories in the sections of glass furnace linings,experiencing the intensive impact of aluminaboronsilicate glasses and basalt melts,has been confirmed and scientifically substantiated.

Hydrogen Reduction:A Novel Method of Synthesizing Ultra-fine Chromic Oxide Powder

The ultra-fine chromic oxide powder was prepared by a novel gas-solid reduction reaction.Na2CrO4 was firstly reduced with hydrogen at 400-600 ℃.The obtained reduction products,mainly the mixture of NaCrO2 and sodium hydroxide（NaOH）,were converted into chromic oxide through hydrolysis followed by calcination.The obtained chromic oxide product was characterized by powder X-ray diffraction（XRD） and SEM.The results show that the hydrolysis process of sodium chromite is the key step and lower reduction temperature helps intensify the hydrolysis process.

Influence of MgO contents on silica supported nano-size gold catalyst for carbon monoxide total oxidation

A series of nano-size gold catalysts were prepared by deposition-precipitation method using silica material promoted with different amounts of MgO as the carrier. The influences of MgO addition on the structure and property of the nano-size gold catalysts were characterized by X-ray diffraction （XRD）, transmission electron microscopy （TEM）, O2 temperature-programmed desorption （O2-TPD）, and inductively coupled with plasma atomic emission spectroscopy （ICP-AES） techniques. The total oxidation of CO was chosen as the probe reaction. The results suggest that for the gold catalysts supported on the silica material after MgO modification, the size of the gold particles is pronouncedly reduced, the oxygen mobility is enhanced, and the catalytic activity for low-temperature CO oxidation is greatly improved. The gold catalyst modified by 6 wt% MgO （Mg/SiO2 weight ratio） shows higher CO oxidation activity, over which the temperature of CO total oxidation is lower about 150 K than that over the silica directly supported gold catalyst.

Effect of nano-size nickel particles on wear resistance and high temperature oxidation resistance of ultrafine ceramic coating

In order to improve the wear resistance and high temperature oxidation resistance of titanium and titanium alloy, the high temperature ultra fine ceramic coating containing nano-size nickel particles was prepared by flow coat method on the surface of industrially pure titanium TB1-0. The effects of nano-size nickel particles on the wear resistance and high temperature oxidation resistance of coating substrate system were investigated through oxidation kinetics experiment and wear resistance test. The morphologies of the specimens were examined by means of optical microscopy, scanning electron microscopy and X-ray diffraction. The results show that the high temperature ultra fine ceramic coating has notable protection effect on industrially pure titanium TB1-0 from oxidation. The oxidation and wear resistance properties of the coating can be effectively improved by adding nano-size nickel particles. The oxidative mass gain of the specimen decreases from 11.33 mg·cm-2 to 5.25 mg·cm-2 and the friction coefficient decreases from 1.1 to 0.6 by adding nano-size nickel particles, and the coating containing 10% （mass fraction） nano-size nickel shows the optimum properties.

Research on the Impact of CeO2 -based Solid Solution Metal Oxide on Combustion Performance of Diesel Engine and Emissions

This paper mainly studies on the performance of high-speed diesel engines and emission reduction when the engine uses heavy oil mixed with nanometer-sized additives Ce0.9 Cu0.1 O2 and Ce0.9 Zr0.1 O2.During the test,Indiset 620 combustion analyzer made by AVL,was used to make a real-time survey on the cylinder pressure,the fuel ignition moment,and establish a relation between the change trend of temperature in cylinder and the crank angle.For the engine burning heavy oil and heavy oil mixed with additives,combustion analysis software Indicom and Concerto were used to analyze its combustion process and emission conditions.Experimental investigation shows that nano-sized complex oxide can improve the performance of diesel engine fueled with heavy oil,and reduce the emission of pollutants like NOx and CO,comparing it with the pure heavy oil.According to the consequences of this experiment,the additives improve the overall performance in the use of heavy oil.

Influence of nano-SiC on microstructure and property of MAO coating formed on AZ91D magnesium alloy

Ceramic coating incorporated with nano-SiC was obtained on AZ91D magnesium alloy during MAO by adding nano-SiC into the silicate-aluminate-based composite electrolyte. The microstructure, thickness, phase analysis, element composition and hardness of the coatings were respectively investigated by scanning electron microscopy（SEM）, film thickness meter, X-ray diffraction （XRD）, energy disperse spectroscopy（EDS） and Vickers hardness tester. The wear resistance of Mg alloy and coatings were evaluated by friction and wear apparatus, while the corrosion resistance of Mg alloy and coatings were evaluated by potentiodynamic polarization test and electrochemical impedance spectroscopy （EIS）. The results show that after adding nano-SiC into the electrolyte, both the striking voltage and final voltage decrease, the size and number of the micropore on the surface of the coating decrease, the thickness and hardness of the coating increase, both the wear resistance and corrosion resistance of the coating raise.

Improving the wear resistance of plasma electrolytic oxidation(PEO)coatings applied on Mg and its alloys under the addition of nano-and micro-sized additives into the electrolytes:A review

As an efficient surface modification approach,the plasma electrolytic oxidation(PEO)technique can boost the capability of wear protection in Mg and its alloys by applying a hard and thick ceramic coating.In this procedure,more efficient protection can be acquired via adding additives(in the form of particle,powder,sheet,etc.)into solutions and producing composite coatings.These additives result in more efficient protection against wear via getting stuck in the cracks and pores of coatings and rising the thickness,hardness,and diminishing the porosity size and content.The efficiency of each additive can be changed owing to its intrinsic properties like melting point,size,participation type(reactive,partly reactive,or inert)and potential of zeta.In this review,the effects of distinct additives in nano-and micro-scale size on wear behavior of PEO coatings on Mg and its alloys is going to be reviewed.

Homogeneous arc ablation behaviors of CuCr cathodes improved by chromic oxide

Cathode ablation is one of the dominant limitations for extending the maximum operating time of arc heaters.In this work,the arc ablation behaviors and mechanisms of commercial CuCr10,CuCr25,and CuCr50 cathodes were investigated for pure copper and pure chromium cathodes.The discharging homogeneity was improved with the increase of chromium content in the cathodes,which was attributed to the formed chromic oxide layer.The CuCr50 cathodes exhibited the lowest ablation rate with a reduction of 27.0%compared to the copper cathodes.The chromic oxide formed in the pit protected the bottom matrix,leading to a homogeneous ablation process.The mechanism for the improved homogeneous ablation behaviors of the CuCr50 cathodes was proposed and featured by the suppression of deep pits and the dispersion of arc foot.Future attention will be focused on designing composite cathodes with an anti-ablation surface layer and a good conductive matrix.

吉富罗非鱼幼鱼对10种饲料原料表观消化率的研究

本试验以0.5%的三氧化二铬(Cr_2O_3)为指示剂研究吉富罗非鱼幼鱼对10种饲料原料的干物质、粗蛋白质、粗脂肪、磷、总能和氨基酸的表观消化率。10种饲料原料分别为玉米蛋白粉、玉米柠檬酸渣、玉米胚芽粕、普通豆粕、发酵豆粕、大豆浓缩蛋白、大豆分离蛋白、麦芽根、鱼粉和蚯蚓粉,试验日粮由70%的基础饲料和30%的试验饲料原料组成。选用初体重为(7.05±0.09)g的吉富罗非鱼苗495尾,随机分为11组,每组3重复,每个重复15尾鱼,其中对照组饲喂基础日粮,试验组分别饲喂1种试验日粮,收集的粪便样品待测。结果表明:10种饲料原料的干物质、粗蛋白质、粗脂肪、磷、总能和氨基酸的表观消化率范围分别为41.7%～98.9%、90.6%～99.6%、73.1%～98.8%、49.5%～99.6%、45.4%～99.7%和83.3%～100%。在10种饲料原料中,鱼粉、蚯蚓粉和大豆分离蛋白的干物质、粗蛋白质、总能表观消化率较高;玉米柠檬酸渣和蚯蚓粉的粗脂肪表观消化率较高;玉米胚芽粕和蚯蚓粉的磷表观消化率较高。蚯蚓粉的总能表观消化率最高,麦芽根的干物质、粗蛋白质、粗脂肪、总能表观消化率最低,大豆浓缩蛋白的磷的表观消化率最低。各原料氨基酸表观消化率的变化趋势与蛋白质表观消化率的趋势一致。由此可知,大豆分离蛋白、蚯蚓粉可视为鱼粉的优良动植物替代物,大豆浓缩蛋白、普通豆粕和发酵豆粕的营养价值略低于大豆分离蛋白、蚯蚓粉和鱼粉,麦芽根的营养价值最低。

甲苯完全氧化反应中含铬催化剂的TPR研究

甲苯完全氧化反应中含铬催化剂的ＴＰＲ研究单绍纯，封雷，孙鸣鸣，伏义路（中国科学技术大学近代化学系，合肥２３００２６）关键词甲苯氧化，三氧化二铬，程序升温还原我们发现，不少非贵金属氧化物催化剂虽然有较好的反应活性，但却不能维持长久，因而影响了其开发应用...

哮喘-慢阻肺重叠综合征、哮喘及慢阻肺患者的肺功能及临床特征比较

目的分析哮喘-慢阻肺重叠综合征(asthma-COPD overlap syndrome,ACOS)、哮喘及慢性阻塞性肺疾病(简称慢阻肺)患者的肺功能及临床特征,以提高ACOS的早期诊治水平。方法收集解放军总医院呼吸科门诊及住院的ACOS、哮喘及慢阻肺患者资料,ACOS组30例,哮喘组30例,慢阻肺组30例;比较3组患者的性别、年龄、肺功能、呼出气一氧化氮(Fe NO)、外周血嗜酸性细胞百分比、血清总Ig E水平及临床症状评分。结果 ACOS组平均年龄(59.1±12.0)岁,60岁以上占50%。ACOS组FEV_1%预计值(55.01%±21.26%)显著低于哮喘组(71.52%±24.80%)(P<0.05);ACOS组吸入β2受体激动剂前FEV_1/FVC%(51.11%±13.17%)显著低于哮喘组(63.95%±13.54%)(P<0.05);ACOS组小气道功能障碍29例(96.7%),显著多于哮喘组的23例(76.7%)(P<0.05);ACOS组RV/TLC%(46.9%±10.5%)显著高于哮喘组(30.3%±6.5%)(P<0.05)。ACOS组DLco-SB%(60.9%±15.9%)显著低于哮喘组(88.3%±16.6%)(P<0.05),但显著高于慢阻肺组(50.5%±16.0%)(P<0.05)。ACOS组FEV_1%pred、FEV_1/FVC%、小气道功能障碍的比例及RV/TLC%与慢阻肺组差异无统计学意义。ACOS组外周血嗜酸性细胞百分比(4.12%±3.86%)显著低于哮喘组(6.65%±6.17%)(P<0.05)。总Ig E升高者在ACOS中占60%,哮喘中占56.7%,慢阻肺中占10%。ACOS组Fe NO值为(43.75±24.29)ppb,显著低于哮喘组的(63.90±52.97)ppb,但高于慢阻肺组的(32.53±18.33)ppb(P<0.05)。临床症状评分3组间差异无统计学意义。结论与哮喘组比较,ACOS组患病年龄大,肺通气功能下降更明显,小气道功能障碍患者比例更多,肺残气量更高,肺弥散功能更差,Fe NO值更低,外周血嗜酸细胞百分比更低。与慢阻肺组比较,ACOS组肺弥散功能更好,总Ig E升高者更多。

铬酸氧化法改善超高分子量聚乙烯纤维表面粘接性能

以特定浓度铬酸氧化液对超高分子量聚乙烯(UHMWPE)纤维进行表面氧化改性。通过傅里叶变换红外光谱、X射线光电子能谱、扫描电子显微镜、X射线衍射和力学性能测试分析比较了处理前后纤维的表面官能团变化、形貌结构、结晶性能和力学性能的变化,并采用微脱粘法和拉曼光谱法研究了纤维-树脂复合材料界面剪切强度及微观受力情况。结果表明,UHMWPE纤维经铬酸氧化处理后,纤维表面极性增加,粗糙程度变大;纤维表面处理的最佳条件为55℃、5min;拉曼光谱研究表明,改性后UHMWPE纤维-环氧树脂界面粘接性能较未改性纤维有明显增强。

氧化钨二氧化钛复合共生薄膜的拉曼光谱结构研究

采用电子束及真空热蒸发的方式镀制了氧化钨薄膜及掺杂的氧化钨的复合共生薄膜。运用拉曼光谱以及电化学工作站等测试手段分析了氧化钨复合共生薄膜的结构及电致变色性能。通过对拉曼光谱曲线的解叠分峰处理发现,源于晶相的810cm-1拉曼峰的相对强度变化与样品的致色效率存在负相关,即拉曼峰相对强度越小,样品的致色效率越高。

Cr－Ag／γ－Al_2O_3催化剂在CO氧化反应中Ag的助催化作用

Ｃｒ－Ａｇ／γ－Ａｌ_２Ｏ_３催化剂在ＣＯ氧化反应中Ａｇ的助催化作用陈平，朱波，钟依均，罗孟飞，李少华，吴红丽（杭州大学催化研究所杭州３１００２８）（杭州大学中心实验室杭州）关键词氧化铬，氧化银，氧化铝，负载催化剂，还原特性，一氧化碳，氧化活性催化燃烧...

硅铬复合氧化物抗结焦涂层的制备及其性能

采用化学气相沉积法在裂解小试装置的裂解炉管内制备了硅铬复合氧化物抗结焦涂层。通过裂解结焦实验、元素分析和SEM方法对硅铬复合氧化物涂层在裂解炉管内的分布规律、抑制结焦能力和抗高温冲击能力以及涂层对烯烃收率的影响进行了研究。在裂解炉管内沉积硅铬复合氧化物涂层时,炉管入口沉积的涂层中含有较多的氧化铬,中间段的涂层主要为硅铬复合氧化物,而出口的涂层含氧化硅较多。所制备的涂层前期结焦抑制率可达90%,在第14次评价周期后,结焦抑制率仍保持在80%以上。硅铬复合氧化物涂层能耐受1 000℃的热冲击,具有较好的牢固度,并对乙烯、丙烯和丁二烯收率的影响不明显。

二苯碳酰二肼光度法测定超基性岩石中三氧化二铬的改进

二苯碳酰二肼光度法是测定微量Cr(Ⅵ)的行业标准方法,以硫酸作为显色介质,酸度要求严格,显色稳定时间短,体系显色后需在10 min～1 h测定完毕,灵敏度较差。本文对标准方法进行改进,将显色介质由硫酸改为磷酸。结果表明,在H3PO4介质中显色剂与Cr(Ⅵ)反应生成的络合物可稳定3 h,方法相对标准偏差(RSD)≤5.25%,加标回收率为99.2%～102.0%,检出限由标准方法的13.6μg/g降至3.8μg/g。建立的方法用于超基性岩标准物质分析,相比于标准方法,稳定性、精密度和准确性均有提高。

掺杂Cr_2O_3,MgO对C_4A_3形成及水化性能影响的研究

研究了掺杂Ｃｒ２Ｏ３，ＭｇＯ对Ｃ４Ａ３Ｓ矿物形成及水化性能的影响．结果表明，在１３００℃保温１ｈ的煅烧条件下，掺加一定量的ＭｇＯ能促进Ｃ４Ａ３Ｓ的形成，而Ｃｒ２Ｏ３则有稳定过渡产物ＣＡ的作用，从而减慢Ｃ４Ａ３Ｓ的形成速度；在１３００℃保温３ｈ的煅烧条件下，掺加Ｃｒ２Ｏ３，ＭｇＯ均能使Ｃ４Ａ３Ｓ的形成量增加．掺杂使Ｃ４Ａ３Ｓ晶体主要以四方晶系的结构形式存在．在本实验条件下，掺杂可提高Ｃ４Ａ３Ｓ的水化反应活性，其原因归结为晶体结构的畸变．

中华鳖幼鳖对4种饲料原料中粗蛋白质和氨基酸的表观消化率

本试验旨在研究中华鳖(Trionyx sinensis)幼鳖对蚕蛹、发酵豆粕、肉骨粉和玉米蛋白粉4种饲料原料中粗蛋白质和氨基酸的表观消化率,以寻求中华鳖新型蛋白质饲料原料。试验饲料由70%的基础饲料和30%的待测饲料原料组成,并以0.5%的三氧化二铬(Cr2O3)作为外源指示剂。选取平均体重为(120.0±1.5)g的中华鳖幼鳖150只,随机分成5组(基础饲料组饲喂基础饲料,其他4组分别饲喂1种试验饲料),每组3个重复,每个重复10只,饲养1周后开始用虹吸法收集粪便,进行粗蛋白质和氨基酸表观消化率的测定。结果表明:1)中华鳖幼鳖对肉骨粉、发酵豆粕、蚕蛹中粗蛋白质的表观消化率分别为90.57%、86.34%、85.75%,显著高于玉米蛋白粉的75.98%(P<0.05)。2)动物性蛋白质源中,中华鳖幼鳖对蚕蛹中总氨基酸的表观消化率较高,为92.44%,对肉骨粉中总氨基酸的表观消化率较低,仅为82.48%;植物性蛋白质源中,中华鳖幼鳖对玉米蛋白粉中总氨基酸的表观消化率较高,为96.56%,对发酵豆粕中总氨基酸的表观消化率为87.90%。综合分析得出,蚕蛹可作为中华鳖幼鳖的优质动物性蛋白质源,发酵豆粕可作为中华鳖幼鳖较好的植物性蛋白质源。

2,2′-联吡啶类催化铬酸氧化异丙醇的动力学研究

铬酸氧化醇类的反应广泛应用于分析和有机合成中。为了加速铬酸的氧化作用或提高反应产率,试验过一些共氧化剂,和催化剂。2,2＇—联吡啶(简作BPy)能与铬离子螯合,显著地提高了铬酸的氧化速率。反应动力学研究的结果说明,2,2＇—联吡啶类、Cr(VI)和异丙醇的三分子螫合物分解为产物一步为限速步骤(见反应式4)。限速步骤产生的Cr(Ⅳ)仍能与2,2＇—联吡啶类螫合,这种作用使Cr(Ⅳ)稳定化,延长了Cr(Ⅳ)的寿命,利于电子转移因而促进反应4的进行。

水合氧化铬的制备与热分解过程的研究

在热压反应釜中利用蔗糖将重铬酸钾直接还原成水合氧化铬,利用TG-DTA,XRD,FT—IR,BET比表面积测定等表征技术对得到的水合氧化铬在空气气氛中的热分解过程进行了研究。结果表明,水合氧化铬热分解过程中存在Cr3+→Cr6+→Cr3+氧化还原过程;O2分子的存在加速了晶型α—Cr2O3的形成;同时发现在“发热或发光现象”发生之前,部分α—Cr2O3微晶已经形成。对热分解过程的机理做了简单的讨论。