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Preparation technology of ultra-fine powders of Auricularia auricular 被引量:12
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作者 杨春瑜 方迪 +1 位作者 王萍 马岩 《Journal of Forestry Research》 SCIE CAS CSCD 2004年第2期150-152,i003,共4页
Conventional mechanical method and mechanical method combined with vacuum freeze-drying technology were used to make the ultra-fine powders of edible fungus (Auricularia auricular). The content of basic nutrients, ami... Conventional mechanical method and mechanical method combined with vacuum freeze-drying technology were used to make the ultra-fine powders of edible fungus (Auricularia auricular). The content of basic nutrients, amino acid, micro structure and their properties of raw edible fungus and the edible fungus powders obtained with the two methods were analyzed and compared. The granularity size and micro-structure of the pulverized samples were analyzed by SEM and TEM technology. The average granularity size of the edible fungus powder obtained with mechanical method was 1–5 μm, while that obtained with mechanical method combined with vacuum freeze-drying process was 0.5–1 μm. The ultra-fine powders of edible fungus obtained with the two methods had better water recovery capability and quality, and their preserving time was longer than that of raw edible fungus. All the properties of the ultra-fine powders of edible fungus obtained with the vacuum freeze-drying technology were evidently superior to that of the conventional mechanical method. Keywords Auricularia auricula - Edible fungus - Ultra-fine powders - Vacuum freeze-drying CLC number TS205 Document code B Biography: YANG Chun-yu (1975), female, Ph. D. in Engineering Technology Center of Forestry and Wood Workine, Machinery, Northeast Forestry University, Harbin 150040, P. R. China.Responsible editor: Zhu Hong 展开更多
关键词 Auricularia auricula Edible fungus ultra-fine powders Vacuum freeze-drying
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Optimal Conditions for Preparing Ultra-Fine CeO_2 Powders in A Submerged Circulative Impinging Stream Reactor 被引量:6
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作者 池汝安 徐志高 +1 位作者 吴元欣 王存文 《Journal of Rare Earths》 SCIE EI CAS CSCD 2007年第4期422-427,共6页
Cerium carbonate powders were produced in a submerged circulation impinging stream reactor (SCISR) from Ce(NO3)3· 6H2O. NH4HCO3 was used as a precipitant in the reaction. Cerium carbonate powders were roasted... Cerium carbonate powders were produced in a submerged circulation impinging stream reactor (SCISR) from Ce(NO3)3· 6H2O. NH4HCO3 was used as a precipitant in the reaction. Cerium carbonate powders were roasted to produce ultra-fine cerium dioxide (CeO2) powders. The optimal conditions of such production process were obtained by orthogonal and one-factor experiments. The results showed that ultra-fine and narrowly distributed cerium carbonate powders were produced under the optimal flowing conditions. The concentrations of Ce(NO3)3 and NH4HCO3 solutions were 02,5 and 0.3 mol · L^-1, respectively. The concentration of PEG4000 added in these two solutions was 4 g · L^-1. The stirring ratio, reaction temperature, feeding time, solution pH, reaction time and digestion time were 900 r · min^- 1,80 ℃, 20 min, 5 - 6, 5 min and 1 h, respectively. The final product, CeO2 powders, was obtained by roasting the produced cerium carbonate in air for 3 h at 500 ℃. The finally produced CeO2 powders were torispherical particles with a narrow size distribution of 0.8 -2.5 μm. The crystal structure of CeO2 powders belonged to cubic crystal system and its space point 5 group was OH^5-FM3M. Under optimal conditions, powders produced by SCISR were finer and more narrowly distributed than that by Stirred Tank Reactor (STR). 展开更多
关键词 impinging stream REACTOR cerium dioxide ultra-fine powder rare earths
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DYNAMIC RHEOLOGICAL BEHAVIOR OF POLYPROPYLENE FILLED WITH ULTRA-FINE POWDERED RUBBER PARTICLES 被引量:7
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作者 郑强 《Chinese Journal of Polymer Science》 SCIE CAS CSCD 2004年第4期363-367,共5页
Dynamic rheological characteristics of polypropylene (PP) filled with ultra-fine full-vulcanized powdered rubber (UFPR) composed of styrene-butadiene copolymer were studied through dynamic rheological measurements on ... Dynamic rheological characteristics of polypropylene (PP) filled with ultra-fine full-vulcanized powdered rubber (UFPR) composed of styrene-butadiene copolymer were studied through dynamic rheological measurements on an Advanced Rheometric Expansion System (ARES). A specific viscoelastic phenomenon, i.e. 'the second plateau', appeared at low frequencies, and exhibits a certain dependence on the amount of rubber particles and the dispersion state in the matrix. This phenomenon is attributed to the formation of aggregation structure of rubber particles. The analyses of Cole-Cole diagrams of the dynamic viscoelastic functions suggest that the heterogeneity of the composites is enhanced on increasing both particle content and temperature. 展开更多
关键词 POLYPROPYLENE ultra-fine powdered rubber Filled polymers Dynamic rheological behavior Aggregation of fillers
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An improved sodium silicate binder modified by ultra-fine powder materials 被引量:5
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作者 WANG Ji-na FAN Zi-tian +2 位作者 WANG Hua-fang DONG Xuan-pu HUANG Nai-yu 《China Foundry》 SCIE CAS 2007年第1期26-30,共5页
This paper presents a new method of modifying sodium silicate binder with ultra-fine powders. The sodium silicate binder modified by ultra-fine powder A and the organic B can reduce the addition amount of the binder. ... This paper presents a new method of modifying sodium silicate binder with ultra-fine powders. The sodium silicate binder modified by ultra-fine powder A and the organic B can reduce the addition amount of the binder. The results indicate that the 24 h strength has increased by 39.9% at room temperature and the residual strength has decreased by 30.7% at 800℃, compared to the conventional sodium silicate. An available material to improve the moisture resistance was also found by adding about 2% more inorganic C, and it can increase the moist strength by 20%. In the end, the microanalyses are given to explain the modifying machanism, i. e., the ultra-fine powder A can refine the sodium silicate binder to avoid holes in the binder bond, which can increase the 24 h strength at room temperture, and can lead to more cracks in the bond after the molding sand is heated to 800℃. This is because of the stress caused by the new eutectic complex of modified sodium silicate binder. 展开更多
关键词 sodium silicate binder modification ultra-fine powder materials bonding strength moisture resistance COLLAPSIBILITY
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Hydrogen Reduction:A Novel Method of Synthesizing Ultra-fine Chromic Oxide Powder 被引量:1
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作者 白玉兰 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 2010年第3期388-390,共3页
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 ... 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. 展开更多
关键词 chromic oxide gas-solid reduction ultra-fine powder
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Strengthening of HT250 by modified ultra-fine ceramic powders 被引量:1
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作者 Bo Yuan Mei-ling Chen +2 位作者 Jun Yang Gui-lin Liu Zhi-ming Yan 《China Foundry》 SCIE 2015年第6期418-424,共7页
In this study, three kinds of modified ultra-fine ceramic powders marked A, B and C, which were prepared by each of three different modifiers mixing with a commercial SiC, were added to HT250 cast iron, respectively, ... In this study, three kinds of modified ultra-fine ceramic powders marked A, B and C, which were prepared by each of three different modifiers mixing with a commercial SiC, were added to HT250 cast iron, respectively, and the effects of the modified ultra-fine ceramic powders on microstructure, mechanical properties and wear resistance were studied. Metallographic examination, tensile test, scanning electron microscopy, and three-dimensional surface topography were applied to analyze and compare the samples containing modified powder with the original samples. The results showed that the most obvious modification effect among the powders was seen in the sample containing powder A, with the graphite and eutectic cells being refined, the tensile strength being increased by 36.9%, and the wear resistance being improved by 45.5% and 47.2% under loads of 150 N and 300 N, respectively. The improvements of mechanical properties and wear resistance in the HT250 cast iron with the modified ultra-fine ceramic powders were attributed to the synergistic effect of the grain refinement with the powder acting as a hard particle phase and the lubrication by the graphite. 展开更多
关键词 modified ultra-fine ceramic powders HT250 MICROSTRUCTURE mechanical properties wear resistance
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Preparation of Ultra-fine Salbutamol Sulfate Particles by Reactive Precipitation and Characterization of Dry Powder Inhalant
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作者 续京 刘晓林 陈建峰 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2008年第5期791-795,共5页
The preparation of ultra-fine particles of salbutamol sulphate (SS) was accomplished with a reactive precipitation pathway, in which salbutamol and sulphuric acid were Used as reactants with the solvents of ethanol.... The preparation of ultra-fine particles of salbutamol sulphate (SS) was accomplished with a reactive precipitation pathway, in which salbutamol and sulphuric acid were Used as reactants with the solvents of ethanol.The effects of sulphuric acid concentration, reaction temperature, stirring rate, and reaction time onthesize of the particle were investigated. A binary mixture composed of lactose and SS was prepared to evaluate SS. The results showed that ultra-fine SS particles with controlled diameters ranging between 3 μm and 0.8 μm and with a narrow distribution could be achieved. The morphology consisting of clubbed particles wassuccess.fully obtained. The purity of the particles reached above 98% with-UV detection. The dose- of dry powder inhalation was obtained by blending the particles with recrystallized lactose, which acted as a carrier. The deposition quantity of the drug in breathing tract was estimated using a twin imPinger apparatus. Compared with the Shapuer powder (purchased in the market), the results showed that SS_particles had more quantifies.subsided in simulative lung.. _ 展开更多
关键词 salbutamol sulphate ultra-fine particle reactive precipitation PREPARATION dry powder inhalant DEPOSITION
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Preparation of Well Dispersed and Ultra-Fine Ce(Zr)O_2 Mixed Oxide by Mechanochemical Processing 被引量:2
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作者 程昌明 李永绣 +1 位作者 周雪珍 陈伟凡 《Journal of Rare Earths》 SCIE EI CAS CSCD 2004年第6期775-779,共5页
Ultra-fine CeO_2-ZrO_2 mixed oxide was successfully synthesized by wet-solid phase mechanochemical processing, Ce_2(CO_3)_3·8H_2O, ZrOCl_2·xH_2O and ammonia were used as reactants. It is found that the cryst... Ultra-fine CeO_2-ZrO_2 mixed oxide was successfully synthesized by wet-solid phase mechanochemical processing, Ce_2(CO_3)_3·8H_2O, ZrOCl_2·xH_2O and ammonia were used as reactants. It is found that the crystalline Ce_2(CO_3)_3·8H_2O and ZrOCl_2·xH_2O are changed to amorphous cerium and zirconium hydroxide precursor after milling with ammonia, and Ce_(0.15)Zr_(0.85)O_2 mixed oxide with pure tetragonal phase structure and medium particle size(D_(50))less than 1μm is formed by calcining precursor over 673 K. The XRD patterns indicate that the crystal unite size increases with rising calcining temperature due to crystal growth. However, the particle size and BET surface area of the Ce(Zr)O_2 mixed oxide decreases with rising calcining temperature, which may be attributed to the contract of particles and the vanish of holes inside grains. 展开更多
关键词 ceria-zirconia mixed oxide ultra-fine powders mechanochemical process rare earths
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微米级铝粉球磨过程中形变的仿真和实验研究
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作者 张昌松 张白亮 高晓阳 《材料科学与工艺》 CAS CSCD 北大核心 2024年第5期58-66,共9页
小粒径的铝粉在燃烧时易形成团聚,会严重影响铝粉的燃烧效率。铝(Al)与聚四氟乙烯(PTFE)通过基于机械活化原理的行星式球磨机工艺制备出的含能材料可以有效地解决团聚问题。本文采用仿真与实验相结合的方法,研究微米级铝粉在球磨的过程... 小粒径的铝粉在燃烧时易形成团聚,会严重影响铝粉的燃烧效率。铝(Al)与聚四氟乙烯(PTFE)通过基于机械活化原理的行星式球磨机工艺制备出的含能材料可以有效地解决团聚问题。本文采用仿真与实验相结合的方法,研究微米级铝粉在球磨的过程中破碎前的塑性变形以及破碎后的粒径变化。由于微米级粉体与磨球尺寸跨度过大,所以采用多尺度仿真,分别对磨球的相对速度分布、粉体应力能量分布以及粉体塑性变形过程中的能量变化进行研究。结果表明:磨球相对速度的法向分量分布呈幂律分布,且77%的碰撞集中在低速区间;对比粉体的应力能量分布与塑性变形时的能量变化,可以得到粉体的形态变化以及不同状态下的粉体数量,塑性变形阶段的最高能量为1.102×10^(-9)J,且粉体应力能量在1.102×10^(-9)J以下的占比为48.75%;对球磨实验中粒径变化进行曲线拟合,其判定系数R^(2)为0.999 46,数值接近于1,具有较强的可预测性;结合破碎前的塑性变形,可以实现对球磨任意时间后的颗粒粒径的预测。 展开更多
关键词 多尺度仿真 行星式球磨机 微米级铝粉 机械活化 形变机理
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不同温湿度条件下微米硼的氧化过程研究
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作者 何志成 吴建军 +7 位作者 杨述明 车碧轩 欧阳 李健 郑鹏 段炼 张宇 程玉强 《装备环境工程》 CAS 2024年第2期12-18,共7页
目的 探究不同温湿度条件下微米硼的氧化层结构特征。方法 利用高温水浴浸泡处理去除原料微米硼的表面氧化层,然后在恒温恒湿条件下对微米硼进行加速氧化,利用扫描电子显微镜、透射电子显微镜和X射线光电子能谱对加速氧化后硼颗粒的氧... 目的 探究不同温湿度条件下微米硼的氧化层结构特征。方法 利用高温水浴浸泡处理去除原料微米硼的表面氧化层,然后在恒温恒湿条件下对微米硼进行加速氧化,利用扫描电子显微镜、透射电子显微镜和X射线光电子能谱对加速氧化后硼颗粒的氧化层厚度及组成进行分析,总结表面氧化层结构及成分组成变化规律,揭示温湿度条件下微米硼的氧化机制。结果 微米硼经高温水浴浸泡处理后,表面氧化层去除率达到50%。随着加速氧化时间的延长,硼颗粒氧化层的厚度逐渐增大,由内向外硼颗粒表面可以用B-B_(x)O_(y)-B_(2)O_(3)三层结构来表示,B_(x)O_(y)总是伴随着B_(2)O_(3)同时出现的,且随着氧化反应的进行,颗粒表面B_(x)O_(y)的含量将超过B的含量。结论 不同温湿度条件下微米硼的氧化机制为O_(2)向B颗粒内部单向扩散的反应机制,B先与O_(2)反应,形成低氧化物B_(x)O_(y),B_(x)O_(y)进而与O_(2)反应生成B_(2)O_(3)。随着氧化层厚度的增加,O_(2)向B颗粒内部扩散的阻力增大,氧化反应速率随之降低。相比湿度的影响,温度的升高可显著加快硼表面氧化层的形成;温度一定时,湿度的增加可促进硼氧化层的形成。 展开更多
关键词 温度 湿度 微米 氧化层 推进剂 点火药
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液态金属改性微米Al-氟聚物的3D打印及性能表征
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作者 陈颖 张世龙 +5 位作者 陈婵娟 何奥 伍波 王军 沈金朋 裴重华 《火炸药学报》 EI CAS CSCD 北大核心 2024年第5期430-437,I0004,共9页
为了研究镓基液体金属(GLM)-Al-氟聚物的能量释放性能,制备了GLM质量分数分别为1%、3%、5%、7%的GLM-Al,通过3D打印获得了GLM-Al-氟聚物复合反应性材料;采用SEM、EDS、XRD、XPS、DSC-TG、高速摄影仪和万能拉伸仪对GLM-Al及GLM-Al-氟聚... 为了研究镓基液体金属(GLM)-Al-氟聚物的能量释放性能,制备了GLM质量分数分别为1%、3%、5%、7%的GLM-Al,通过3D打印获得了GLM-Al-氟聚物复合反应性材料;采用SEM、EDS、XRD、XPS、DSC-TG、高速摄影仪和万能拉伸仪对GLM-Al及GLM-Al-氟聚物的微观结构、燃烧性能、力学性能等进行测试。结果表明,质量分数3%的GLM改性的GLM-Al放热量和氧化增重均最大,分别为6181 J/g和42.92%;改性前的Al-氟聚物不能被点燃,改性后GLM-Al-氟聚物可以点燃且可以持续稳定燃烧,在当量比为3.5时的燃速最大,为6.0 mm/s;此时GLM-Al-氟聚物的抗拉强度和断裂伸长率均最大,分别为1.73 MPa、11486%,是改性前Al-氟聚物的1.5倍和1.3倍。 展开更多
关键词 增材制造 镓基液态金属 GLM 微米铝粉 氟聚物 3D打印 燃烧
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Magnéli相亚氧化钛陶瓷的制备及其应用研究进展
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作者 刘会军 肖浩宇 +2 位作者 乔永莲 杨凌旭 曾潮流 《材料研究与应用》 CAS 2024年第1期37-50,共14页
Magnéli相亚氧化钛是一系列非化学计量比氧化钛的统称,主要包括Ti_(4)O_(7)、Ti_(5)O_(9)、Ti_(6)O_(11)和Ti_(8)O_(15)等相,其中以Ti_(4)O_(7)的导电性最好,其理论电导率可达1500 S·cm^(-1),约为石墨的二倍。此外,Magné... Magnéli相亚氧化钛是一系列非化学计量比氧化钛的统称,主要包括Ti_(4)O_(7)、Ti_(5)O_(9)、Ti_(6)O_(11)和Ti_(8)O_(15)等相,其中以Ti_(4)O_(7)的导电性最好,其理论电导率可达1500 S·cm^(-1),约为石墨的二倍。此外,Magnéli相亚氧化钛在强酸、强碱环境中均表现出极强的耐蚀性能,并且能够在水溶液中保持3.0 V以上的稳定电位窗口。Magnéli相亚氧化钛优异的性能使其在化学电源如铅蓄电池、液流电池、锂硫电池、可再生燃料电池,电解水的催化剂载体,热电及光电材料,光催化制氢以及电催化氧化降解有机污染物等领域中展现出良好的应用前景。目前,科研人员已经开发出一系列制备亚氧化钛的方法。但是在高纯度、单相、纳米或亚微米尺度亚氧化钛粉体,大尺寸的一体式亚氧化钛电极和金属基亚氧化钛涂层电极的规模化生产和应用中依然存在许多问题,限制了亚氧化钛系列产品在上述领域中的广泛应用。基于Magnéli相亚氧化钛陶瓷的固有特性,重点介绍了亚氧化钛粉体、一体式电极和涂层电极的制备方法及应用现状,同时对亚氧化钛相关材料的应用前景进行了简要概述,为科研院所及相关企业提供了参考依据、研究思路和解决办法。 展开更多
关键词 Magnéli相 亚氧化钛 Ti_(4)O_(7) 纳米粉体 亚微米粉体 一体式电极 靶材 涂层电极
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再生微粉混凝土叠合板弯曲性能试验研究
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作者 张平 何江湖 +5 位作者 丁聪 颜肃 吴翔 李庆 邢鹏飞 尹为民 《低温建筑技术》 2024年第4期144-148,共5页
为实现建筑固废的资源化利用,文中将水泥净浆固体废料及废弃红砖分别制备成再生水泥浆粉(RSP)和再生砖粉(RBP)当做胶凝材料使用来制作叠合板,以研究不同微粉对混凝土叠合板弯曲性能的影响。研究结果表明,再生微粉叠合板受弯破坏过程与... 为实现建筑固废的资源化利用,文中将水泥净浆固体废料及废弃红砖分别制备成再生水泥浆粉(RSP)和再生砖粉(RBP)当做胶凝材料使用来制作叠合板,以研究不同微粉对混凝土叠合板弯曲性能的影响。研究结果表明,再生微粉叠合板受弯破坏过程与普通混凝土叠合板的受弯破坏过程基本一致,但开裂荷载、屈服荷载和极限荷载有所不同;再生微粉替代水泥时,会一定程度上降低极限荷载,不同再生微粉对板极限荷载的影响程度不同;对照普通板时,极限荷载最高降低幅度为16.5%,最低降低幅度为10.6%;但是,再生微粉替代粉煤灰时,极限荷载下降程度不明显,对照普通板时,极限荷载降低幅度仅为3.6%。因此,研究可以为再生微粉在叠合板中的应用提供试验依据。 展开更多
关键词 再生微粉 叠合板 弯曲性能 极限荷载
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再生微粉和矿物掺合料对水泥浆体微观结构的影响研究
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作者 马丽媛 李滢 陈曦 《青海大学学报》 2024年第1期24-31,共8页
为推动建筑垃圾资源化利用的发展,本文利用核磁共振和压汞两种试验方法研究再生微粉和矿物掺合料以不同比例掺配后对水泥净浆、水泥砂浆微观结构的影响规律。结果表明:水泥净浆单掺再生微粉时,随着掺量的增加,净浆的孔隙度增加,内部无... 为推动建筑垃圾资源化利用的发展,本文利用核磁共振和压汞两种试验方法研究再生微粉和矿物掺合料以不同比例掺配后对水泥净浆、水泥砂浆微观结构的影响规律。结果表明:水泥净浆单掺再生微粉时,随着掺量的增加,净浆的孔隙度增加,内部无害孔和少害孔数量变少,有害孔和多害孔数量变多,净浆内部结构致密性较差;砂浆单掺再生微粉时,随着掺量的增加,砂浆的平均半径和总孔隙率增大,相比于S0,S3的总孔隙率增加44.2%,平均半径提高50.3%;相对于单掺砂浆,复掺粉煤灰和硅灰后总孔隙率和平均半径呈降低趋势,相比于S0,FS1的总孔隙率降低18.1%,平均半径降低7.8%。复掺再生微粉与矿物掺合料能有效改善水泥浆体孔结构,从而减少水泥用量。 展开更多
关键词 水泥浆体 再生微粉 孔结构 核磁共振 压汞
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Synthesis and Characterization of Nano-sized Boron Powder Prepared by Plasma Torch 被引量:5
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作者 黄志军 吴青友 +3 位作者 李祥 尚书勇 戴晓雁 印永祥 《Plasma Science and Technology》 SCIE EI CAS CSCD 2010年第5期577-580,共4页
Hydrogen thermal plasma jet was employed to prepare nano-sized boron powder with hydrogen reduction of BCI3. The maximum yield of nano-sized boron powders was about 50% with the operational conditions of H2/BCl3 of 4.... Hydrogen thermal plasma jet was employed to prepare nano-sized boron powder with hydrogen reduction of BCI3. The maximum yield of nano-sized boron powders was about 50% with the operational conditions of H2/BCl3 of 4.5:1, total feed of 4.9 m3/h, and plasma power of 25 kW. The samples were analyzed by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), and inductively coupled plasma - mass spectrometry (ICP-MS), inductively coupled plasma - atomic emission spectrometry (ICP-AES), inductive combustion infrared absorption (ICIA) and infrared thermal conductivity of oxygen and nitrogen analyzer (ITCA). The results show that the boron powders have different crystal structures with higher dispersion and purity. The average diameter is about 50 nm, and the purity is 90.29% or so. This new technology can use simple process to produce high quality boron powders, and is feasible for industrial production. 展开更多
关键词 NANO-SIZED boron powder thermal plasma ultra-fine powder
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Preparation of Reactive Powder Concrete Using Fly Ash and Steel Slag Powder 被引量:5
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作者 彭艳周 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 2010年第2期349-354,共6页
To decrease the cement and SF content of RPC by using ultra-fine fly ash (UFFA) and steel slag powder (SS), the effect of these mineral admixtures on compressive strength of RPC were investigated. The experimental... To decrease the cement and SF content of RPC by using ultra-fine fly ash (UFFA) and steel slag powder (SS), the effect of these mineral admixtures on compressive strength of RPC were investigated. The experimental results indicate that the utilization of UFFA and SS in RPC is feasible and has prominent mechanical performance. The microstructure analysis (SEM and TG-DTG-DSC) demonstrated that the excellent mechanical properties of RPC containing SS and UFFA were mainly attributed to the sequential hydration filling effect of the compound system. 展开更多
关键词 ultra-fine fly ash steel slag powder reactive powder concrete sequential hydration MICROSTRUCTURE STRENGTH
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Preparation of Ultrafine Tungsten Powder by Sol-Gel Method 被引量:1
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作者 Yuxian HAN Tai QIU Tao SONG 《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 2008年第5期816-818,共3页
Sol-gel method was employed for the preparation of nanoscale tungsten powder. The effects of different preparation conditions on particle size were discussed and the optimum preparation condition was found. The produc... Sol-gel method was employed for the preparation of nanoscale tungsten powder. The effects of different preparation conditions on particle size were discussed and the optimum preparation condition was found. The products were characterized by X-ray diffraction, scan electron microscopy and so on. The results show that the intermediate is monoclinic WO3, its particle shape is approximately spherical, and the particle size distribution is narrow. The average particle size is about 60 nm. After deoxidization, WO3 turns into cubic tungsten powder with small particle size (average particle size about 120 nm) and narrow size distribution. 展开更多
关键词 Sol-gel method Tungsten trioxide Deoxidize ultra-fine tungsten powder
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Evaluating Simultaneous Impact of Slag and Tire Rubber Powder on Mechanical Characteristics and Durability of Concrete
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作者 Mostafa Amiri Farzad Hatami Emadaldin Mohammadi Golafshani 《Journal of Renewable Materials》 SCIE EI 2022年第8期2155-2177,共23页
In this experimental study,the impact of Portland cement replacement by ground granulated blast furnace slag(GGBFS)and micronized rubber powder(MRP)on the compressive,flexural,tensile strengths,and rapid chloride migr... In this experimental study,the impact of Portland cement replacement by ground granulated blast furnace slag(GGBFS)and micronized rubber powder(MRP)on the compressive,flexural,tensile strengths,and rapid chloride migration test(RCMT)of concrete were assessed.In this study,samples with different binder content and water to binder ratios,including the MRP with the substitution levels of 0%,2.5%and 5%,and the GGBFS with the substitution ratios of 0%,20%and 40%by weight of Portland cement were made.According to the results,in the samples containing slag and rubber powder in the early ages,on average,a 12.2%decrease in the mechanical characteristics of concrete was observed,nonetheless with raising the age of the samples,the impact of slag on reducing the porosity of concrete lowered the negative impact of rubber powder.Regarding durability characteristics,the RCMT results of the samples were enhanced by using rubber powder because of its insulation impact.Moreover,adding slag into the MRP-included mixtures results in a 23%reduction in the migration rate of the chloride ion averagely.At last,four mathematical statements were derived for the mechanical and durability of concrete containing the MRP and GGBFS utilizing the genetic programming method. 展开更多
关键词 micronized rubber powder ground granulated blast furnace slag waste materials mechanical properties DURABILITY
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Crystal Structure of Ba<sub>x</sub>Sr<sub>1-x</sub>TiO<sub>3</sub>Fine Powder
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作者 Natheer B. Mahmood Emad K. Al-Shakarchi +1 位作者 Brahim Elouadi Xavier Feaugas 《Journal of Modern Physics》 2015年第1期70-77,共8页
Various compositions of the system BaxSr1-xTiO3 (BST) have been elaborated both as fine powders and ceramic monoliths, using the co-precipitation route within a warmed supersaturated solution of oxalic acid. The appro... Various compositions of the system BaxSr1-xTiO3 (BST) have been elaborated both as fine powders and ceramic monoliths, using the co-precipitation route within a warmed supersaturated solution of oxalic acid. The appropriate stoichiometry was determined from the mixtures of precisely titrated aqueous solutions of cations chlorides (SrCl2, BaCl2, and TiCl4). The reason of this process was to apply low sintering temperature in production of BST samples with ultra-fine powders. These powders primarily calcined at (850°C) for (5 hr) were used to elaborate ceramics after pellets sintering at (1200°C) during (8 hrs). Indeed, XRD patterns were confirmed that the samples are a pure phase and a perovskite cubic structural type at (x = 0, 0.5, 0.6). Whereas, (x = 0.7, 0.8, 0.9, 1) showed a tetragonal phase. There is agreement between the FTIR and XRD analysis, by the relation of the wave vector (K) and lattice constant. It was deduced a stimulated relation between (x) and (K). The results of TEM, they were clear that the lowest particle sizes investigated of BST powders nearly (36 - 50 nm). 展开更多
关键词 Barium Strontium TITANATE OXALATE CO-PRECIPITATION Method X-Ray Diffraction Transmission Electron Microscope ultra-fine powder
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再生微粉对砂浆性能的影响研究
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作者 邢晓飞 苏彩丽 《砖瓦》 2023年第5期16-18,共3页
为了解决建筑垃圾资源化利用问题,提出了利用再生微粉替代部分水泥,研究再生砂浆流变性能和力学性能。通过不同再生微粉掺量,分析了再生砂浆的流动性与强度,研究结果表明:经过1h研磨的再生微粉掺量不超过10%时,再生微粉可以提高再生砂... 为了解决建筑垃圾资源化利用问题,提出了利用再生微粉替代部分水泥,研究再生砂浆流变性能和力学性能。通过不同再生微粉掺量,分析了再生砂浆的流动性与强度,研究结果表明:经过1h研磨的再生微粉掺量不超过10%时,再生微粉可以提高再生砂浆的流动度,对再生砂浆的7d抗压强度有所提升,对砂浆28d强度会有所下降。当再生微粉掺量超过10%时,砂浆流变性、强度都会下降。 展开更多
关键词 再生微粉 砂浆 流变性 强度
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