Preparation of Europium Doped Silicon Based Oxynitride Phosphor by Polymer-Derived Method

采用先驱体转化法制备含铕氮氧化物荧光粉。通过热分析结果确认聚碳硅烷与乙酰丙酮铕的聚合温度;通过对不同氮化温度之后样品碳含量的检测以及失重情况的分析,确认含铕聚碳硅烷的氮化温度;通过XRD结果确认最终的烧结温度。利用该方法初步制备出了铕掺杂硅基氮氧化物荧光粉,采用XRD、荧光光谱等手段分析所得荧光粉的结构与发光性能,所得的荧光粉在375 nm波长激发下,发射峰位于550 nm,基质相为α-Si_3N_4和β-Si_3N_4的混合相。Europium doped silicon based oxynitride phosphor was prepared by polymer-derived method.Thermal analysis results confirm the polymerization temperature of polycarbosilane with Eu(AcAc)3;the nitridation temperature was confirmed by the analysis of weight loss and carbon content;the final sintering temperature was confirmed by the XRD results.The Eu doped silicon based oxynitride phosphor was successfully prepared by this method.The structure and photoluminescence of this phosphor was analyzed by XRD and fluorescence spectra.The results show that the excitation peak was located at 375 nm,the emission peak was located at 550 nm,and the crystal structure was the mixture of α-Si_3N_4 and β-Si_3N_4

Permeability investigation of nitric acid in a tetrafluoroethylene-hexafluoropropylene (F46) container

推进剂在改性氟塑料聚全氟代乙丙烯(F46)内囊内的渗漏不可避免,通过设计特定的装置,用浓硝酸替代推进剂,利用离子色谱检测存放不同时间后渗透出内囊的硝酸根离子的含量来评价内囊的防渗透性能,采用扫描电子显微镜对改性氟塑料膜的内表面进行表征。研究发现,随着浸泡时间的增加,硝酸根离子的渗透速率减慢并趋于平稳,由最初的每天约8μg/g下降到最后的约1μg/g。氟塑料内囊的内壁表面被腐蚀,腐蚀物堵塞了自由体之间的间隙,从而导致硝酸渗透速度的降低。It is inevitable for possible permeation of corrosive chemical substances stored in a tetrafluoroethylene-hexafluoropropylene(F46) container due to the spaces between the chain segments of F46. A specially designed device was used in this paper to investigate the permeability of nitric acid which was a substitute of corrosive chemical substance in an F46 container. An ion chromatogram(IC) was employed to examine the permeability of the container by detecting the changes in concentrations of nitrate ions during different periods of F46 membrane immersion in ultra-pure water. Surface morphologies of F46 membrane before and after the immersion were studied by scanning electron microscopy(SEM). It is found that the permeable rate of nitrate ions is slow down and is virtually unchanged as the immersion time increase. The inside surface of F46 membrane corroded appreciably, which reduces the permeability velocity acid

不同羧酸对钒改性硅酸铁锂结构性能的影响（英文）

采用溶胶-凝胶法得到前驱体,再通过固相烧结法制备10%钒改性碳包覆硅酸铁锂正极材料,系统考察了3种羧酸（即柠檬酸、乙酸、草酸）添加剂对10%钒改性碳包覆硅酸铁锂正极材料的晶相结构、表面形貌、界面特性和电化学性能的影响.结果表明,3种羧酸添加剂制备的材料都能得到结晶性较好的P21和Pmn21混合相结构,主要杂质相为铁,此外还存在少量偏硅酸锂杂质.以柠檬酸、乙酸、草酸为添加剂合成的10%钒改性碳包覆硅酸铁锂正极材料在0.1C倍率下的首次放电容量分别为144.7、140.3和168.7 mAh·g-1,最大容量分别为155.9、145.3和172.0 mAh·g-1出现在第7、15和2周,经50周循环后容量保持率分别为68.2%、76.7%和59.4%.柠檬酸单位分子内含有3个羧酸根,以柠檬酸为添加剂合成的材料残留碳含量最高为7.8%,促进了铁杂质的形成,较大的电荷传质电阻（147Ω）使得库仑效率较低,循环性能较差.相反,乙酸分子中只含有一个羧酸根,以乙酸为添加剂合成的材料中铁杂质相最少,电荷传质电阻（73Ω）最低,导致容量保持率最高,循环性能最好.草酸分子中含有两个羧酸根,以草酸为添加剂合成的材料形成较大的花状形貌,得到合适的残留碳含量（6%）,极大地提高了锂离子迁移率(3.85×10-15cm2·s-1),从而取得超过一个锂离子（1.05）的脱嵌.Supported by The National Natural Science Foundation of China(No.11372263

Measurement of heat flux distribution of supercritical kerosene fueled supersonic combustor

Heat flux distribution of supercritical kerosene fueled, single-side expanded supersonic combustor with two dislocated cavities was experimentally studied. The effects of inlet Mach number, total temperature, mass flow rate and fuel equivalence ratio on the combustion and heat transfer characteristics in the supersonic combustor were analyzed. The isolator inlet Mach number is 2.0 and 2.5, the total temperature is 1305 K to 1701 K and the mass flow rate is 2.0 kg/s to 3.0 kg/s. Pilot hydrogen and liquid or supercritical (773±20 K) China No.3 kerosene were injected in front of the cavities with the equivalence ratio ranges from 0.52 to 0.88. Results show that heat flux increases with the inlet temperature and mass flow rate, however, the influence of equivalence ratio is non-monotonic in the range of this study. The two inlet Mach numbers also trigger different combustion modes, which further complicates the heat flux distribution. In the end, a three parameter correlation is proposed and fitted to normalize the experiment results for comparison and discussion. © 2016, American Institute of Aeronautics and Astronautics Inc, AIAA. All rights reserved

Directional region growing algorithm and its applications in vessel segmentation

针对医学图像中微细管道结构灰度连续性差,采用常规区域生长法进行分割容易丢失末梢的问题,提出一种定向区域生长算法,可以在生长过程中跨越管道结构中的低灰度区域。算法向图像中已生长区域外灰度最高的方向进行生长,每次将一个体素加入已生长区域,将图像转变为一颗以种子点为根结点的树,再从叶子结点进行回溯以确定感兴趣区域。对实现算法的数据结构进行了讨论。算法可以应用于任意维的图像。对2维和3维图像的测试结果表明,相对于常规的区域生长法,算法可以分割出更多的血管分支。算法对3维图像的运行时间为秒钟量级,可以满足临床应用的要求。Accurate extraction of the vasculature in medical images is prerequisite to structural analysis and further applications such as surgical planning.Region growing algorithm is a simple and effective method to extract thick blood vessels which makes use of the spatial continuity of the vascular tree,while the extraction result of small vessels like hepatic artery is unacceptable.In order to solve the problem that the continuity of tenuous vasculature is poor in medical images and vessel segmentation based on traditional region growing may lose distal branches,a directional region growing(DRG) algorithm is proposed which can skip the low gray area in the vasculature during the growing process.The algorithm grows towards the direction of the maximum gray around the grown region,and adds one voxel to the grown region in each iteration.The image is transformed into a tree after the growing process in which the seed point is the root.A trace back procedure beginning from the leaf nodes of the tree can finally determine the region of interest(ROI).The algorithm relaxes the conditions to determine ROI,and small area with low gray in the ROI is permitted.There are two time-consuming steps in the algorithm due to the enormous amount of data in 3D medical images,one is to determine the growing direction in each iteration,the other is to construct the paths from the seed point to leaf nodes during the trace back procedure.Data structure to improve the speed of the algorithm is discussed.The algorithm can be applied to images with any dimension.The algorithm is tested with 2D and 3D images.In both conditions,the segmentation results obtained by DRG contain more distal branches in comparison with traditional region growing algorithm.To some vein phase CT images with poor quality,the proposed algorithm can also generate better results.Four parameters should be appointed in the algorithm and the empirical values are given.The computational time of the algorithm on 3D images is several seconds,which is acceptable in clinical applications.The surface of the extracted vasculature is rough due to the discrete nature of digital images,and further study is needed to smooth the surface before visualization.国家自然科学基金项目(60701022;30770561

Aluminum Coating on Modified Fluorinated Polymer Composite Films

[中文文摘]采用射频磁控溅射技术在改性氟塑料表面沉积铝层,制备了金属/氟化高聚物复合薄膜。利用场发射扫描电镜(FESEM)及能量散射谱(EDS)分析仪对沉积的铝层进行了表面形貌的表征和化学组分的分析。初步探讨了溅射功率、气压和时间等不同溅射参数对铝层结构和铝层在氟塑料表面附着情况的影响。结果表明:溅射功率是决定复合薄膜质量的重要因素,功率过低得不到致密的铝层结构,而且铝层容易从氟塑料表面脱离,功率过高则会产生很强的热效应而使复合薄膜弯曲。溅射气压和时间分别影响铝层在氟塑料表面的沉积速率和生长厚度。[英文文摘]Aluminum film was grown on modified fluorinated polymer composite films by rf magnetron sputtering.Surface morphology and composition of the A1 film were characterized with field emission scanning electron microscopy(FESEM) and energy dispersive spectroscopy(EDS) to optimize A1 film growth conditions.The results show that the sputtering power significantly affects the compactness of the A1 film.Low sputtering power results in less compact A1 film and weak interfacial adhesion,whereas high sputtering power overheats and considerably bends the compositefilms. Wefound that sputteringpressure and sputteringtime determine the deposition rate and thicknessof the A1film, respectively.国家863计划国防先进材料重大专项基金资助项目(No.2003AA305040

R&D of composite thin films

［中文文摘］复合薄膜材料由于具有传统复合材料和薄膜材料两者的优点,正成为复合材料的重要分支而越来越引起广泛的重视和深入的研究。它可以把各层薄膜材料的优异性能结合起来,从而克服各自的弱点,达到特定的应用目的。本文简要综述了近十年来复合薄膜领域的研究进展,介绍了多层复合薄膜的制备方法和常用表征手段并总结了目前复合薄膜材料领域中存在的主要问题。［英文文摘］Having the advantages of both conventional composite materials and thin films,the composite thin films have been more and more attractive in materials technology and widely used in mamy fields.The reason why composite thin films are so attractive is just that they can combine the advantages of each amd every layer of a film together and get rid of the disadvantage of each one,thus serving the special purpose of application.Reviews briefly the R&D of composite thin films in recent ten years and describes the preparation of composite multilayer thin films and commonly used characterixation procedures,and indicaters mainly the existing problems of such thin films.国家863计划国防先进材料重大专项基金资助项目(2003AA305040

LaCoO3-TiO2纳米管阵列的构筑及可见光光催化性能

TiO2纳米管阵列具有较高的光催化活性,但可见光吸收弱,限制了其太阳能利用和环境应用。窄带隙的钙钛矿（ABO3）型氧化物能够吸收大范围波段的可见光,且稳定性高,但光催化活性低。本文首先采用溶胶-凝胶法合成了LaCoO3纳米颗粒,然后利用电泳沉积技术将LaCoO3纳米颗粒修饰于TiO2纳米管阵列表面,构筑了LaCoO3-TiO2纳米管阵列。扫描电子显微镜（SEM）、透射电子显微镜（SEM）、X射线衍射（XRD）和X射线光电子能谱（XPS）的表征结果显示溶胶-凝胶法合成的纳米颗粒为LaCoO3,其尺寸均匀,结晶度高,平均粒径约为100nm。LaCoO3纳米颗粒与TiO2纳米管阵列之间的结合力好。紫外可见吸收光谱（DRS）显示,随着电泳沉积时间的延长,LaCoO3-TiO2纳米管阵列的吸收带边逐渐红移700nm。可见光下光催化降解甲基橙（MO）的结果表明,电泳沉积15 min制得的LaCoO3-TiO2纳米管阵列对MO的光催化效率最高,其降解速率是相同条件下TiO2纳米管阵列的4倍。光致发光光谱和电化学阻抗谱证实LaCoO3纳米颗粒的负载有效地促进了光生电荷的分离和传输,可见光光催化活性明显增强。国家自然科学基金(21621091);;\n广东省自然科学基金(2016A030313845)资助项目~

LaNiO3/TiO2纳米管阵列的电化学制备及其光催化性能

利用脉冲电沉积与高温退火相结合的方法制备了镍酸镧（LaNiO3）纳米颗粒负载的二氧化钛（Ti O2）纳米管阵列.修饰于Ti O2纳米管阵列上的LaNiO3纳米颗粒粒径小（<10 nm）、分布均匀、负载量可控,一些LaNiO3纳米颗粒沉积于Ti O2纳米管内.紫外可见吸收光谱显示,LaNiO3/Ti O2纳米管阵列的吸收带边较Ti O2纳米管阵列明显红移,可见光吸收明显增强.可见光下光催化降解罗丹明B（RhB）的结果表明,脉冲循环沉积500次制得的LaNiO3/Ti O2纳米管阵列的光催化活性最佳,其对RhB光催化降解速率是Ti O2纳米管阵列的3.5倍,并且表现出极好的光催化稳定性

聚碳硅烷熔体的稳态流变性能

采用自制装置对聚碳硅烷(PCS)熔体进行预处理。通过预处理获得三种不同分子量的PCS,并对其进行物理化学和稳态流变性能测试。结果表明,预处理后的PCS其数均分子量为1000 g/mol~1400 g/mol,属低聚物。在温度范围240℃~260℃和剪切速率范围0.001 s-1~10 s-1内有明显的剪切变稀现象。在测试的温度范围内,剪切变稀区的非牛顿指数随温度升高先减小后增大。预处理后的PCS粘流活化能为120 kJ/mol~180 kJ/mol,比一般高聚物的高得多