BaTiO3/铁氧体复合材料的制备及性能

采用传统溶胶-凝胶法和改进的柠檬酸盐溶胶-凝胶法制得了钛酸钡,并对其进行了比较。采用柠檬酸-EDTA的联合络合溶胶-凝胶法制得了针状纳米锶铁氧体磁性微粒,并将钛酸钡和锶铁氧体进行了复合。利用XRD对样品的物相进行分析,利用TEM对样品形貌和粒径进行表征,利用振荡样品磁强计（VSM）对样品进行了磁性能研究,并利用矢量网络分析仪对粉末的电磁波吸收性能进行了表征。结果表明,在2～6GHz范围内,钛酸钡质量分数为30%的复合材料在850℃煅烧2h后吸波性能最佳,最大吸收量为28dB,10dB频带宽度为1.7GHz。     

锆溶胶的制备、稳定及氧化锆粉体的特性

以氧氯化锆为前驱体,采用溶胶-凝胶法快速制备锆溶胶,凝胶后经煅烧制得氧化锆粉体,分析了锆溶胶的制备、稳定和氧化锆粉体的特性。结果表明：随着H_2O_2与ZrOCl_2·8H_2O摩尔数的比值m的增大,锆溶胶形成所需的pH值也逐渐增大；m为4～6,且pH值为3～4．5时,所得的溶胶最稳定；随m值的增大,凝胶干燥后氧化锆粉体粒径减小,分布变窄；m为4时,氧化锆粉体的平均粒径为21．4μm。粉体在450℃热处理时有四方相ZrO_2析出,随着温度升高,四方相ZrO_2结晶趋于完整,并开始析出少量单斜相；900℃时亚稳态四方相大部分转化成单斜相；1020℃时转变完成,此时得到粉体粒径在100nm左右。     

压力和功率对EIGA制备TA15粉末的影响

气雾化是制备增材制造原材料金属粉末的主要方法。该文针对钛合金得粉率低和球形度差问题,采用电极感应熔炼气雾化（EIGA）技术制备TA15钛合金3D打印专用粉末,通过扫描电子显微镜（SEM）和激光粒度仪测试分析手段,研究制粉工艺参数气雾化压力和熔炼功率对粉末粒径分布及形貌的影响规律。研究结果表明,随着雾化气体压力的增大,TA15粉末粒径减小,细粉收得率显著提高,但当雾化压力增加到5 MPa时形成大量卫星粉导致粉末收得率降低至38%;雾化压力的增大会导致气体速度提高,增加气体和金属液的相对速度与动能,使金属液滴的一次破碎和二次破碎更加充分,导致金属粉末粒径减小,但雾化压力增加到一定程度,会使导流管下方回流区面积增加影响粉末形貌。此外,随着熔炼功率的增加TA15钛合金溶液过热度增加,改善其黏度逐渐提高了粉末收得率,由25 k W时的26%增加为40 k W的42%。从粉末收得率、粒度和形貌等因素综合考虑,适合TA15钛合金粉末的最佳制备工艺参数为：熔炼功率40 k W,气雾化压力4.4 MPa,此时细粉收得率为42%,粉末球形度高。     

纳朱SnO2薄膜的制备及其表征

采用溶胶-凝胶法在玻璃基体表面制备纳米SnO2薄膜，通过热处理使其晶化。通过原子力显微镜（AFM）形貌分析表明，在20～80nm的粒径范围内，可通过工艺配方参数的调整人为控制SnO2薄膜的颗粒大小。通过工艺优化制得粒径为27nm左右的薄膜，薄膜颗粒较小，分布均匀，薄膜的透明性好。X射线衍射（XRD）结果表明，随着热处理温度的增加，SnO2特征峰愈来愈尖锐明显，晶体结构趋于完全。Zeta电位分析表明，添加分散剂溶胶的Zeta电位比未添加分散剂溶胶的Zeta电位高；Zeta电位越高，溶胶稳定性越好。     

CaO-B2O3-2SiO2干凝胶制备及其生物模拟矿化现象

采用溶胶一凝胶和常压干燥法制备了CaO-B2O3-2SiO2干凝胶。首次研究了干凝胶在37℃,初始pH=9的K2HPO40．25M水溶液中的生物模拟矿化现象,采用XRD、FTIR和SEM分析了干凝胶及其矿化产物的微观结构和形貌。研究表明,CaO-B2O3-2SiO2干凝胶具有硼硅二元复合氧化物的网络骨架,经矿化反应10d后可转变成呈交叉形式排列的片状碳酸羟基磷灰石晶体,并具有多孔状微观形貌结构。     

金属Co／聚丙烯酰胺复合粉体的γ—射线辐照制备

从Ｃｏ＾２＋－丙烯酰胺有机单水溶液体系出发，采用γ－射线辐照合成制备金属Ｃｏ粒子均匀分散在聚丙烯酰胺基质中的Ｃｏ／聚丙烯胺复合粒子和相应粉体，其中粒子的平均粒径小于１５ｎｍ。作者着讨论辐照过程中烯酰胺单体的聚合对金属粒子生长形貌 和粒径的影响。     

具有缓冲层的ZnO光阳极染料敏化太阳电池研究

摘要：采用乳液聚合技术合成聚苯乙烯微球（polystyrenespheres,简称PS）,利用浸提法,在透明的导电玻璃（SnO2：F,简称FTO）基底上制备PS胶晶阵列模板;然后,继续采用浸提法,将ZnO溶胶灌注于PS阵列模板上,煅烧后,制得多孔结构的ZnO缓冲层。采用水热法合成ZnO纳米线,并将其分别涂覆于干净的FTO基底和具有ZnO缓冲层的FTO基底,制成光阳极。利用X射线衍射仪（XRD）和环境扫描电子显微镜（SEM）,对光阳极光电转换材料进行结构和形貌表征分析。     

铁-镍纳米粉末的制备及其表征

通过差热分析、透射电镜和X射线衍射分析等方法，对以硝酸铁和硝酸镍为主要原料，采用溶胶-凝胶法和化学共还原法制取的镍质量分数分别为10％和20％的铁-镍纳米粉末进行了表征，同时比较聚乙二醇和柠檬酸在制备凝胶时的分散效果。结果表明：以柠檬酸为分散剂，制备的铁-镍纳米粉末的粒径在：30nm左右，成分为(Fe，Ni)和少量(Ni，Fe)Fe2O4的混合物，无其他杂质。     

介孔二氧化钛的制备与研究

以钛酸四丁酯为原料,用聚乙二醇型非离子表面活性剂作为模板剂,采用溶胶-凝胶法制备出了纳米二氧化钛介孔粉体;利用光催化降解甲基橙的实验研究了不同模板剂,不同模板剂添加量以及不同煅烧温度下制备出的介孔TiO2的光催化活性,得出介孔TiO2的最佳制备工艺,并与纳米二氧化钛的光催化性能进行对比。采用X射线粉末衍射分析法（XRD）,透射电镜分析法（TEM）对样品的微观结构、颗粒形态、分布情况、晶型以及物相组成等方面进行表征,验证了实验得出的最佳制备工艺的可靠性。     

BaTi03/铁氧体复合材料的制备及性能

采用传统溶胶-凝胶法和改进的柠檬酸盐溶胶-凝胶法制得了钦酸钡,并对其进行了比较.采用柠檬酸-EDTA的联合络合溶胶-凝胶法制得了针状纳米锶铁氧体磁性微粒,并将钛酸钡和锶铁氧体进行了复合.利用XRD对样品的物相进行分析,利用TEM对样品形貌和粒径进行表征,利用振荡样品磁强计(VSM)对样品进行了磁性能研究,并利用矢量网络分析仪对粉末的电磁波吸收性能进行了表征.结果表明,在2～6GHz范围内,钛酸钡质量分数为30%的复合材料在850℃煅烧2h后吸波性能最佳,最大吸收量为28dB,10dB频带宽度为1.7GHz.     

Minimal Realization of Linear Graph Models for Multi-physics Systems

An engineering system may consist of several different types of components,belonging to such physical"domains"as mechanical,electrical,fluid,and thermal.It is t...     

Quantum Cooperative Robotics and Autonomy

The intersection of Quantum Technologies and Robotics Autonomy is explored in the present paper.The two areas are brought together in establishing an interdisci...     

考虑进油孔有限长滑动轴承油膜力的近似解析解

针对具有进油孔的有限长滑动轴承油膜力求解问题,采用变分原理和分离变量法,求得了有限长滑动轴承油膜压力分布的近似解析表达式。将油膜压力分布的近似解析表达式在油膜存在区域上进行积分,即得到了油膜力。将提出的计算有限长滑动轴承油膜力方法与无限长轴承模型、有限元方法的计算结果进行了比较,发现了提出的方法与有限元方法的计算结果很接近。最后,研究了进油孔位置和进油压力对油膜存在区域、油膜力等的影响,研究结果表明进油孔位置和进油压力对油膜存在区域和油膜力有较大的影响。     

三绕组变压器的双绕组等效建模及在Matpower中的应用

针对实际电网存在着大量的三绕组变压器,但国际上一些著名商业软件,如BPA仿真软件、Matpower这一权威潮流计算开源软件,均只提供双绕组变压器模型,限制了其在具有三绕组变压器的电力系统中的应用的问题,潮流计算是自主开发的电力系统各种应用软件的核心模块,因此依托国际权威开源程序进行二次开发,是一种较好的选择。对Matpower要求的数据格式进行了归纳,对变压器的一般的等值电路及带理想变压器的等值电路和带标幺值的等值电路进行了分析研究,提出了三绕组变压器转换为双绕组等效模型的建模方法,使得原先只适应双绕组变压器的潮流计算软件可以适用于三绕组变压器电网的潮流计算;最后以Matpower软件为例进行了案例计算,并用PSASP仿真软件进行对比验证。研究结果证明,所提出的建模方法是有效的。     

On the Relation of Load to Average Gap in the Contact Between Surfaces with Longitudinal Roughness

A computer simulation model for the contact between longitudinally-oriented rough surfaces has been formulated. This model closely duplicates the actual surf ace contact deformation behavior by taking into account the elastic interactions between the asperities. There were no assumptions made about the shapes, or any deformation behavior of the asperities, except for their obeying the laws of elasticity. The plastic deformations on the high asperity peaks were taken into account by setting a ceiling on their contact pressures at the material hardness value. The simulations used real surface profiles which were digitized from unworn circumferentially ground steel surfaces. Each pair of these profiles was mathematically combined to form an equivalent rough profile pressing against an infinitely rigid flat and having the appropriately adjusted elastic modulus. A total of 28 different pairs of profiles were used in the simulations. Each contacting pair was subjected to 30 different load levels and the local contact pressures and deformations were calculated. The contact simulations yielded some important mathematical relationships between parameters, such as the real area of contact, average gap, and average asperity load through statistical curve fitting. Two analytical functions were generated to relate the average load to average gap and the real area of contact to load.     

Fifth International Summer School on Screw-Theory Based Methods in Robotics

正3-11 September,2014University of Bologna,Bologna,Italy www.summerscrews.org summerscrews2014.ing.unibo.it SUMMER 20SCREWS 14In 2014,our screw-theory school comes to the world's oldest university.In early September,Summer Screws'14 will gather six experts in the application of screw theory in robotics and up to 40 participants at the University of Bologna,Bologna,Italy.The school will teach attendees how to apply existing methods and empower them to develop new ones in their own research.The basic theoretical notions will be introduced in a rigorous manner,emphasizing examples,applications,and exercises.Scholarships are available.     

电站锅炉模糊风险评价方法研究与应用

针对电站锅炉风险等级评价问题,将模糊综合评价技术应用到电站锅炉风险等级评价中。开展了电站锅炉失效影响因素及模糊评价因素的重要程度分析,建立了一套科学合理适于在线评价的电站锅炉风险评价体系,提出了模糊综合评价技术与改进的模糊层次分析法相结合的模糊风险评价方法,利用改进的模糊层次分析法计算了指标体系中各层指标权重。对某一台电站锅炉的实际运行工况影响子因素进行了模糊风险评价,采用模糊合成算子进行模糊综合运算得到电了站锅炉运行工况影响子因素的评价向量。研究结果表明:电站锅炉的运行工况影响子因素的风险评价等级为第6级,失效可能性等级为小,该电站锅炉运行工况良好。     

INDUSTRIAL ENGINEERING AND VISUALISATION-A PRODUCT DEVELOPMENT PERSPECTIVE

Taking the actual project of teaching and researching process for example, the relationship between the industrial engineering and product development is discussed. And use the novel visualization technology to support the industrial engineering and product development. How to use the new computer modeling and simulating technologies to support the product development and industrial engineering, is introduced especially. The support includes both domestic products and industrial systems. The visualization and computer technologies take a very important role in some system or multi-direction modeling, those technologies mentioned above can help the industrial engineers study the effect of design on the whole life circle, including the producing steps. So the engineers can avoid making the wrong decision which may cause bad effects on the whole industrial engineering.     

Non-monotonic material contrast in scanning ion and scanning electron images

30 keV Ga⁺ focused ion beam induced secondary electron (iSE) imaging was used to determine the relative contrast between several materials. The iSE signal compared from C, Si, Al, Ti, Cr, Ni, Cu, Mo, Ag, and W metal layers does not decrease with an increase in target atomic number Z₂, and shows a non-monotonic relationship between contrast and Z₂. The non-monotonic relationship is attributed to periodic fluctuations of the stopping power and sputter yield inherent to the ion–solid interactions. In addition, material contrast from electron-induced secondary electron (eSE) and backscattered electron (BSE) images using scanning electron microscopy (SEM) also shows non-monotonic contrast as a function of Z₂, following the periodic behavior of the stopping power for electron–solid interactions. A comparison of the iSE and eSE results shows similar relative contrast between the metal layers, and not complementary contrast as conventionally understood. These similarities in the contrast behavior can be attributed to similarities in the periodic and non-monotonic function defined by incident particle–solid interaction theory.     

Application of Feature Extraction through Convolution Neural Networks and SVM Classifier for Robust Grading of Apples

This paper proposes a novel grading method of apples,in an automated grading device that uses convolutional neural networks to extract the size,color,texture,an...