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1.
采用熔融法工艺制备了不溶性硫磺(IS),优化设计影响IS含量及稳定性的因素,考察淬冷液温度对IS含量及稳定性的影响,并分别建立了一元线性回归模型。结果表明,熔融法制备IS的适宜条件为:使用含0.05%碘的四氯化碳饱和溶液为稳定剂,恒温温度220℃,恒温时间20 min;复合稳定剂SBS(苯乙烯-丁二烯-苯乙烯嵌段共聚物)/碘/四氯化碳稳定效果较好,其用量为0.05%:0.05%:2.5%。随着淬冷液温度的下降,IS含量及稳定性增加,淬冷液温度与IS含量及稳定性之间均呈线性负相关性。  相似文献   

2.
多腔体的微型可降解高分子聚合物PLGA药物缓释系统是一种新型植入式给药微器件,其载体结构是结合药物释放的要求和高分子聚合物生物降解特性进行设计并利用MEMS工艺制备.为了解微型给药系统实际释药的性能,需要对其进行建模和仿真研究.基于体溶蚀的Monte Carlo溶蚀模型,建立了具有多腔体的微型PLGA给药载体的释药模型,并对腔体结构为圆形的微型给药系统进行了释药过程仿真.仿真结果表明本文建立的微系统释药模型可以较为准确的描述微系统的释药过程,仿真模型对进一步开发微型PLGA给药系统有重要的参考价值.  相似文献   

3.
陈婷婷  曹光群  杨成 《软件学报》2008,21(3):505-508
利用聚乙二醇(PEG)包覆脂质体以提高脂质体的稳定性。先用薄膜分散一超声乳化法制备维生素C脂质体,然后将PEG溶液与维生素C脂质体混合制备PEG包覆的脂质体。电镜照片证明PEG在脂质体外形成了一层膜,粒径增加。脂质体经PEG包覆后包封率增加。稳定性试验测定不同温度下脂质体吸光度变化及脂质体中丙二醛含量变化情况,得到较佳贮存条件为4℃避光,PEG包覆后的脂质体吸光度与丙二醛含量增大幅度均较小。结果表明:用PEG可有效包覆维生素C脂质体并提高脂质体的稳定性。  相似文献   

4.
为实现光纤光栅传感器胶接固定于桥梁缆索钢丝以监测缆索索力,利用胶接结构的剪切测试、钢丝疲劳测试和循环加卸载测试分别对光纤光栅传感器支座与钢丝间胶接结构的剪切性能、疲劳可靠性以及胶接光纤光栅传感器的测试性能进行评估.试验发现:光纤光栅传感器支座与桥梁缆索钢丝间的胶接结构具有较大的剪切载荷,且200万次疲劳载荷对其胶接结性能影响较小;胶接固定于钢丝上的光纤光栅传感器可测出钢丝加卸载的滞回效应,并每个循环加、卸载的波长和钢丝承载载荷关系呈线性且分别重合.结果表明:内置光纤光栅传感器的胶接固定结构具有良好的剪切力学性能和疲劳可靠性,可保证其光纤光栅传感器的测试具有良好的准确、稳定、可靠性.  相似文献   

5.
以二甲基亚砜(DMSO)水溶液为溶剂,采用冷冻—解冻法制备高度透明的物理交联聚乙烯醇(PVA)凝胶膜,将该膜在刚果红溶液中浸泡,制备了物理交联刚果红—聚乙烯醇(PCGR—PVA)凝胶膜。利用紫外—可见光谱法测试该凝胶膜的pH敏感特性,并与化学交联的刚果红—聚乙烯醇(CCGR—PVA)凝胶膜做了对比分析。结果表明:PCGR—PVA和CCGR—PVA凝胶膜均具有良好的pH敏感性,在pH为0.29~4.33范围内对pH呈较好的线性响应,PCGR—PVA凝胶膜的灵敏度更高。PCGR—PVA凝胶膜的响应时间在弱酸中小于10 s,在强酸中小于200 s。表明PCGR—PVA凝胶是优异的pH传感材料。  相似文献   

6.
陈绪胄  李建平 《传感技术学报》2007,20(11):2373-2376
通过自组装依次将纳米银粒子和辣根过氧化酶(HRP)固定到巯基乙胺(Cys)修饰的玻碳电极上,制备了HRP/Ag/Cys膜修饰电极.用交流阻抗技术表征了电极的自组装过程.用循环伏安法和计时电流法考察了HRP与电极之间的直接电化学行为及酶对过氧化氢电催化特性.电极响应对过氧化氢有良好的电催化还原性质,性能稳定,响应时间小于5 s.有望应用于制备第三代生物传感器  相似文献   

7.
该文提出了一种制备新型导热填料的方法:基于液氮驱动和冰模板法自组装,以氮化硼纳米 片和银纳米颗粒为基本组装单元,制备了具有开放孔结构、内部互连的毫米级氮化硼气凝胶球。其 中,对气凝胶球的成型机理进行了初步的探索,并对影响气胶球微观结构的因素,如制备气凝胶球 浆料的固含量等进行研究。另外,该文将环氧树脂灌入到多孔气凝胶球中,从而制得氮化硼球/环氧 树脂和氮化硼-银球/环氧树脂复合材料,并对其结构形貌和导热性能进行了研究,其中重点研究了氮 化硼纳米片的表面改性、氮化硼微球的不同微观结构对复合材料的导热性能的影响。结果显示,当多 孔微球的填充量为 2.7 vol% 时,氮化硼球/环氧树脂复合材料的面外导热系数达 0.57 W/(m·K),而氮 化硼-银球/环氧树脂复合材料的面外导热系数达 0.64 W/(m·K),相比于纯环氧树脂的导热系数提高了 276.5%。由此可见,氮化硼气凝胶球微球的加入可有效提高环氧树脂基复合材料的导热系数,在氮化 硼纳米片表面负载银颗粒后可进一步提升复合材料的导热性能;液氮驱动的冰模板法自组装技术在制 备导热填料领域具有巨大的应用前景。  相似文献   

8.
制备了以掺钇氧化锆(YSZ)为固态电解质,LaFeO3为敏感电极的混成电势乙醇气体传感器,LaFeO3通过溶胶-凝胶法制备并用XRD分析,利用场发射电子扫描显微镜对YSZ基底和敏感电极表面形貌进行了表征, 测试结果表明制备的传感器在350℃的工作条件下对乙醇有良好的响应(400×10-6乙醇时135mV)和较快的响应时间(50×10-6乙醇时14s), 测试结果还表明此传感器有良好的可重复性和选择性。  相似文献   

9.
血红蛋白-硅酸铝凝胶膜制备及其对H2O2的生物传感研究   总被引:1,自引:0,他引:1  
夏亚莉  干宁 《传感器世界》2006,12(1):15-19,29
基于血红蛋白-硅酸铝(Hb-AlSiO4)凝胶膜修饰电极,制备了一种非媒介体型的过氧化氢生物传感器,血红蛋白在修饰电极上能给出直接电化学.用傅立叶变换红外光谱(FTIR)、扫描电子显微镜(SEM)、X-光电子能谱(XPS)和电化学技术对包埋Hb和未包埋Hb的AlSiO4凝胶进行了表征.凝胶层表面化学洁净,具有凝胶固有的多孔结构,形态均一而且粒径分布均匀.得到的AlSiO4凝胶修饰电极能有效地保持酶的活性,在长时间的保存过程中能维持好的稳定性.同时,对于过氧化氢的电化学还原表现出良好的催化活性,测定了米氏常数Km,该传感器在1×10-6~4×10-4mol/L的过氧化氢浓度范围内有良好的线性关系,检测限是5×10-7mol/L.该装置具有灵敏、稳定、易于制备的优点.  相似文献   

10.
以六水硝酸镁Mg(NO3)2·6H2O和尿素CO(NH2)2为原料,以柠檬酸C6H7O8·H2O,无水乙醇为稳定剂,采用溶胶—凝胶法制备纳米氧化镁粉末,研究了在不同工艺条件下(柠檬酸,水,无水乙醇的用量)对溶胶—凝胶体系的稳定性的影响.并采用X-射线粉末衍射仪(XRD)和红外光谱仪对产物进行了表征。结果表明,未引入柠檬酸时,溶胶—凝胶体系的稳定性差;引入了柠檬酸后,当水:六水硝酸镁:尿素:柠檬酸:乙醇=100:9:6:9:2.1(摩尔比)时可形成稳定的凝胶体系。  相似文献   

11.
Healthcare, the largest global industry, is undergoing significant transformations with the genesis of a new technology known as the Internet of Things (IoT). Many healthcare leaders are investing more money for transforming their services to harness the benefits provided by IoT, thereby paving the way for the Internet of Medical Things (IoMT), an extensive collection of medical sensors and associated infrastructure. IoMT has many benefits like providing remote healthcare by monitoring health vitals of patients at a distant place, providing healthcare services to elderly people, and monitoring a large group of people in a region or country for detection and prevention of epidemics. This paper provides a review of IoT in the healthcare domain by first describing the enabling technologies for delivering smart healthcare, followed by some of the key applications of IoT in healthcare. Next, a fog-based architecture consisting of three layers for IoT-based healthcare applications is proposed. Finally, we focus on some of the open challenges of IoT in healthcare, like fault tolerance, interoperability, latency, energy efficiency, and availability. Existing solutions for these challenges are also discussed.  相似文献   

12.
Computer Simulation will play an important role in future changes in Education. Here we will review how the Spanish National Project for Computers in Education, called Atenea, looks at Modelling and Simulation and how the first training courses for teachers, recommended by this project, are being carried out. We will give particular attention to the applications of the Simulation in the classroom using System Dynamics techniques. A real case study, developed by the pupils of a Simulation course for teachers, is outlined showing numerical and graphics results. Afterwards, SDSE—System Dynamics Simulator for Education—is superficially described: it is a microcomputer based system which has been developed by the authors to assist the process of building and simulating System Dynamics models in educative environments.Finally, some pedagogical applications, alternatives of use and major problems of the Simulation in educational environments are presented.  相似文献   

13.
毛君  徐广明  罗丁 《微计算机信息》2004,20(10):117-118
本文探讨了计算机网络技术下的CAD/CAM集成系统.提出了一种协同环境下的CAD/CAM集成系统,并构造了其网络体系结构和其系统的框架结构。  相似文献   

14.
This paper presents the results of survey of the availability and use of computers in a preschool sample in Chile, and compares them with similar results of primary and secondary schools. Results show that although preschools have relatively low access to computers and teachers have relatively low ICT competencies, they declare similar ICT related obstacles and impacts compared to their colleagues in secondary schools. Also, results show that preschool students seem to use computers in the classroom more frequently than their peers in primary and secondary schools and that the activities they implement are focused on developing key curriculum related areas implementing tasks that can be associated to the exercising of key competencies and skills. This specialised use of computers in preschools, which is much more focused than the activities with computers reported by teachers in higher levels, could be explained by the relative low variety of educational software available in these preschools, the availability of the computers in the classroom rather than in labs; the special type of teaching and learning activities implemented at this age level and/or due to the relative lack of teachers' ICT competencies. On the one hand, these results highlight the need for further research, and on the other, it constitutes an interesting lesson for policy designer that tend to advocate for considering computers as “multipurpose” technologies that should be used across subjects, levels and teaching strategies. In this case, computers seem to play a very specific and concrete role in preschools classrooms that, eventually, contributes to improve students' outcomes, which highlights the potential of considering the use of computers, software and other technologies to improve specific subject areas at particular levels while designing ICT in education policies for this age group.  相似文献   

15.
RSS技术以其独特的优势在网络信息行业得到了广泛的应用,这些优势有望解决教育中的一些难题,但如何在教育领域进行有效的应用,目前尚缺少成熟的模式。对目前已有的应用实践进行探讨,从理论上建构出一个在教育中应用的框架模型,并利用开源代码SXNA实现部分主要功能。  相似文献   

16.
Three Nordic countries, Denmark, Finland and Norway, participated in the IEA SITES 2006 study. All the three countries have launched huge policy and investment programmes to promote digital literacy and readiness for the information age. In relation to the remarkable Finnish Programme for International Student Assessment (PISA) results, it is interesting to see if the Finnish school system may be better suited to ground and contextualize pedagogical practice with Information and Communication Technologies (ICT) than the Danish and Norwegian counterparts. One main difference is that the Finnish system seems to anchor decisions about and interpretations on how ICT should be utilized stronger at the local level than the two other systems. One of the general goals in the policy programmes is to get teachers to innovate with ICT in the classrooms. The Second Information Technology in Education Study (SITES) 2006 indicators for two innovative pedagogical orientations, lifelong learning orientation and connectedness are utilized to compare teachers from the three nations. The main findings is that Finnish teachers are either not differing or they are scoring significantly lower on the two indicators than teachers from Denmark or Norway. The exception is Finnish science teachers who are more inclined towards using ICT in lifelong learning practices than their Danish and Norwegian counterparts. Generally, the Finnish teachers seem to be more autonomous in their pedagogical choices but may also be more conservative than the Danish and Norwegian teachers in making use of ICT.  相似文献   

17.
在工程实践中,需要从具有多个相似点阵的已知点阵(Spot Array)集[S]中匹配出一个与未知点阵[P]最相似的点阵[P*],然后对两个点阵做样本点匹配。完成这个任务的关键挑战在于如何匹配出与未知点阵[P]最相似的已知点阵[P*]。这个问题比较新颖,目前少有理论研究,文中探索出一种基于图形的几何特征分析的描述算法,算法首先将每个点阵构建成一个唯一的简单图(Simple Graph)轮廓图形,同时为每个图形构建一个链式结构,然后利用轮廓图形的几何特征计算未知点阵与各已知点阵的相似程度,匹配出相似度最高的一个,最后利用链式结构完成两个点阵间的样本点匹配。该算法不受点阵的坐标系旋转和尺度缩放的影响。通过实验表明,该算法能够快速、准确地完成点阵相似度比较和样本点匹配任务。  相似文献   

18.
讨论了时间信息传输的网络时延对时间用户网上校时精度的严重影响。提出了一种严格消除网络时延的技术方案,并指出这种新方法对网络授时和各种网上通信的重要意义。  相似文献   

19.
高职院校"双师型"专业教学团队的打造,教师队伍"双师"素质的提高在高职院校高速发展的今天尤为重要,如何提高教师团队的"双师"素质?笔者结合近几年专业建设的实践认为鼓励教师广泛开展社会服务,对提高教师的专业技能、提高教师的教育教学能力、提高教师的服务意识等都有一定的促进作用。  相似文献   

20.
传统的边缘检测算子仅在空域上对梯度图像进行阈值分割来计算二值边缘图像,当应用在自然场景图像中时,检测结果中往往含有大量的干扰边缘。为了消除干扰边缘,提高传统边缘算子的轮廓检测性能,提出了基于空频域联合阈值分割的轮廓检测方法:首先对梯度图像进行频域阈值分割消除干扰边缘,然后进行空域阈值分割得到最终的二值边缘图。结合Canny算子,利用自然场景图像对该方法进行了性能评估,结果表明,该方法大大减少了干扰边缘,有效提高了Canny算子在复杂自然场景图像中的轮廓检测性能。  相似文献   

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