首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 78 毫秒
1.
真空蒸发沉积聚苯胺—TCNQ复合薄膜的STM研究   总被引:1,自引:0,他引:1  
李建昌  薛增泉 《真空》1999,(6):6-9,10
利用扫描隧道显微镜对真空蒸发沉积的聚苯胺-TCNQ(PANI-TCNQ)复合薄膜、纯聚苯胺薄膜及纯TCNQ薄膜试样进行了对比分析。研究发现,纯PANI薄膜和纯TCNQ薄膜都是绝缘膜,而用TCNQ挽杂获得具有较高导电特性的PANI-TCNQ复合薄膜。而且与表面粗糙不连续的PANI薄膜和TCNQ薄膜相比,PANI-TCNQ复合薄膜易形成较大面积的表面结构完善的连续膜。傅里叶变换红外光谱(FTIR)分析  相似文献   

2.
三嵌段共聚物合成SiO2中孔材料的制备化学   总被引:4,自引:0,他引:4  
采用溶胶-凝胶法,以正硅酸乙酯(TEOS)为前驱体,添加聚氧乙烯醚(PEO)-聚氧丙烯醚(PPO)-聚氧乙烯醚(PEO)共聚物为模板剂制备结构可控的SiO2中孔材料,通过BET、TG/DTA、FT-IR、^29SiNMR等分析手段,  相似文献   

3.
小型星模拟器中星图动态显示系统的设计   总被引:17,自引:2,他引:15  
阐述了星图动态显示系统的工作原理和系统要求,讨论了TFT-LCD在星图动态显示系统中的应用方法,提出了TFT-LCD的电路实现方案,对星图动态主要软件的设计进行了分析和研究。  相似文献   

4.
TEOS—PEG无机—有机杂化复合材料的研究   总被引:6,自引:0,他引:6  
阐述了溶胶-凝胶法合成TEOS-PEG无机-有机杂化复合材料的基本原理,且成功地合成出该材料,同时材料了红有征及热分析,探索了TEOS-PEG凝胶比表面积、折射率及结构的影响因素,TEOS-PEG无机-有机杂化复合材料具有优良的物化性能及光学性能,可广泛用作各种特殊用途的光学元件。  相似文献   

5.
分析了J-T阀气流的流动特性及相关参数的影响,给出了计算程序框图,并对用于4.4K/0.5W闭式循环制冷机的J-T阀进行了计算,得出了其通道孔径和长度的关系曲线及最佳参数,针对目前普遍采用的可调J-T阀的不足之处,提出了一种新型的电磁式可J-T阀,论述了它的结构特点和作用。  相似文献   

6.
分析了J-T阀中气流的流动特性及相关参数的影响,给出了计算程序框图,并对用于4.4K/0.5W闭式循环制冷机的J-T阀进行了计算,得出了其通道孔径和长度的关系曲线及最佳参数。针对目前普遍采用的可调J-T阀的不足之处,提出了一种新型的电磁式可调J-T阀,论述了它的结构特点和作用。  相似文献   

7.
7075T73510合金断裂韧性和疲劳裂纹扩展   总被引:4,自引:0,他引:4  
研究了7075T73510合金的断裂韧性和疲劳裂纹扩展行为,分析不同方向性能差异的原因。结果表明:合金的断裂韧性依赖于取向。L-T方向的断裂韧性值远大于T-L方向。而其疲劳裂纹扩展速率对应力比更敏感,无论T-L还是L-T方向,R=0.6时的FCGR值是R=0.1时的二倍左右。在相同应力比和较小的△K下,两个方向的FCGR值基本无差异。文中认为:呈带分或串状分布的杂质相对T-L向怕裂韧性影响较大。  相似文献   

8.
廖雅萍 《影像技术》1999,(2):13-17,56
本文介绍了1-苯基-5-巯基-1,2,3,4-四氮唑的化学特性和照相特性;评价了分析测定了PMT纯度的方法;了PMT五种不同的合成路线,并对较有实际意义的有方法用实际加以验证。  相似文献   

9.
本文介绍了混合物节流制冷机中逆流热交换器的换热量温度分布图(q-T)及换热量火用分布图(q-τe)的计算原理,并给出了一类混合物工质(N2+C2H6+C3H8)的q-T及q-τe图的计算结果与分析。g—T及q-τe图的计算与混合物节流制冷机的优化有直接关系。  相似文献   

10.
热处理对卤化银多晶光纤显微结构的影响   总被引:1,自引:0,他引:1  
热挤压法成型的卤化银多晶光纤,经不同温度热处理后,光纤的显微结构发生了变化。扫描电镜形貌分析结果显示,热处理温度T≤170℃,显微结构未发生变化,晶粒尺寸1-2μ。T=200℃时,晶粒尺寸10-20μm;T=250℃时,晶粒尺寸20-30μm;T=300℃时,晶粒尺寸30-40μm;光纤显微硬度测量结果也显示,热处理温度〉170℃后,光纤的显微硬度随热处理温度的升高而,在200℃附近硬度降低最低值  相似文献   

11.
Scientometrics - The European Research Council (ERC) is one of the leading sources of research funding worldwide. This article analyses the papers published by its grantees. The primary aim was to...  相似文献   

12.
The National Institute of Standards and Technology (NIST) has prepared and certified SRM 1507, a freeze-dried urine fortified with 11-nor-delta 9-tetrahydrocannabinol-9-carboxylic acid (THC-9-COOH), the major urinary metabolite of marijuana. The certified concentration of 20 +/- 1 ng/mL for the analyte was obtained from the concordant results of analyses of the material by gas chromatography/mass spectrometry (GC/MS) and high-performance liquid chromatography with electrochemical detection (HPLC-EC). Solid-phase extraction was used to prepare the sample for GC/MS analyses, and liquid-liquid extraction was used for the HPLC-EC analyses. The multistep HPLC method was developed at NIST to circumvent interferences from urinary constituents. The results of a round robin test on this material among five Department of Defense laboratories involved in drug testing are reported.  相似文献   

13.
Polystyrene/high-density polyethylene (PS/HDPE) blends were synthesized by melt blending in a single screw extruder. Co-continuity measurements using solvent extraction and scanning electron (SEM) micrographs showed that co-continuity was obtained around 35% PS. Thermal analyses measurements revealed a reduction in crystallinity of the HDPE phase around the co-continuous composition. Raman analyses across the entire composition range of these blends showed an increase in the normalized integral intensities of the 1128 cm(-1) and 1061 cm(-1) stretching vibrations of the HDPE molecules. The presence of all-trans HDPE chains that are not packed into an orthorhombic structure is used to explain the simultaneous occurrence of reduced crystallinity and increased intensity of all-trans HDPE stretch vibrations.  相似文献   

14.
两种新型咔唑类双光子光聚合引发剂的合成与光学性质   总被引:4,自引:0,他引:4  
报道了两种新型的咔唑类双光子光聚合引发剂,3,6-双[2-(4-吡啶基)乙烯基]-9-苯基咔唑(1) 和 3,6-双[2-(2-吡啶基)乙烯基]-9-苯基咔唑(2),它们是通过钯催化的Heck偶连反应合成得到,并用元素分析,红外光谱,核磁共振氢谱和电喷雾电离质谱等对它们进行了全面的表征.这两个A-π-D-π-A结构的咔唑衍生物具有很好的单光子和双光子荧光行为,我们也详细研究了它们的溶剂效应和作为双光子引发剂用于微结构的制备,并讨论了它们的引发聚合的机理.  相似文献   

15.
Nitrite is an important intermediate species in the biogeochemical cycling of nitrogen, but its role in natural aquatic systems is poorly understood. Isotopic data can be used to study the sources and transformations of NO2- in the environment, but methods for independent isotopic analyses of NO2- in the presence of other N species are still new and evolving. This study demonstrates that isotopic analyses of N and O in NO2- can be done by treating whole freshwater or saltwater samples with the denitrifying bacterium Stenotrophomonas nitritireducens, which selectively reduces NO2- to N2O for isotope ratio mass spectrometry. When calibrated with solutions containing NO2- with known isotopic compositions determined independently, reproducible delta15N and delta18O values were obtained at both natural-abundance levels (+/-0.2-0.5 per thousand for delta15N and +/-0.4-1.0 per thousand for delta18O) and moderately enriched 15N tracer levels (+/-20-50 per thousand for delta15N near 5000 per thousand) for 5-20 nmol of NO2- (1-20 micromol/L in 1-5 mL aliquots). This method is highly selective for NO2- and was used for mixed samples containing both NO2- and NO3- with little or no measurable cross-contamination. In addition, mixed samples that were analyzed with S. nitritireducens were treated subsequently with Pseudomonas aureofaciens to reduce the NO3- in the absence of NO2-, providing isotopic analyses of NO2- and NO3- separately in the same aliquot. Sequential bacterial reduction methods like this one should be useful for a variety of isotopic studies aimed at understanding nitrogen cycling in aquatic environments. A test of these methods in an agricultural watershed in Indiana provides isotopic evidence for both nitrification and denitrification as sources of NO2- in a small stream.  相似文献   

16.
Using an acetate-alkoxide sol-gel route in which the precursors are barium acetate, yttrium isopropoxide and titanium diisopropoxide bis-acetylacetonate, we prepared a ferroelectric material with the formula: Ba1-xYxTiO3, x = 0.005. SEM analysis showed a polymeric microstructure of the gel due to the chelated titanium alkoxide precursor used as starting materials. The evolution of the structure and microstructure of the precursor gel heated at temperatures up to 1000 degrees C was studied by various techniques. The powder obtained by heating the gel at 1100 degrees C presented a homogeneous structure consisting of submicronic particles (approximately 200 nm). XRD and SAED analyses revealed that Ba0.995Y0.005TiO3 nanocrystals of about 5-10 nm appeared at 600 degrees C, together with BaCO3. The presence of barium carbonate was identified also by IR spectroscopy and thermal analyses. The ceramics obtained from the as-prepared powder presented good dielectric properties (capacitance = 840 pF/dielectric constant = 3860 and dielectric loss (tandelta) = 0.078 at Curie temperatures of 120-121 degrees C).  相似文献   

17.
β-MnO2 single crystals with novel tetragonous morphology have been hydrothermally prepared in an HCl solution at 180 °C for 24 h without using templates, catalysts, and organic reagents. The structure of the obtained β-MnO2 was systematically investigated by X-ray diffraction, SEM and TEM microscopy, FT-IR spectroscopy, DSC-TGA analyses, and chemical compositional analyses. The morphology of β-MnO2 could be controlled by the hydrothermal treatment temperatures and the hydrothermal reaction times. β-MnO2 single crystals with diameters 200-600 nm and lengths up to 1-5 μm not only had novel tetragonous morphology, but also had high purity.  相似文献   

18.
通过吡咯与二茂铁甲醛的缩合反应合成了含茂类金属的共轭高分子-聚[吡咯-2,5-二(二茂铁甲烯)](PPDFcE)及其前聚物聚[吡咯-2,5-二(二茂铁甲烷)](PPDFcA).通过红外、核磁、紫外,元素分析鉴定了产物及其前聚物的结构。利用DSC、TGA及TGA-IR测试分析了所合成聚合物的热学性质,紫外光谱表明PPDFcE的能隙为1.13eV,属窄能隙共轭聚合物,经碘掺杂后产物的电导率在10^-7S/cm,而掺杂TCNQ的产物的导电率达到了10^-2S/cm。  相似文献   

19.
电镀非晶态镍钨合金工艺研究   总被引:3,自引:0,他引:3  
万小波  张林  周兰  肖江 《材料保护》2006,39(12):23-25
研究了电镀非晶态镍钨合金工艺,采用EDS、XRD等手段检测了镍钨合金镀层,并将工艺条件如电流密度Jc、镀液pH值、镀液温度等对镀层的影响进行了比较,得出非晶态镍钨合金电镀的最佳工艺:[W]/([W] [Ni])为0.6~0.8,Jc=6.0~12.0 A/dm2,温度55~65℃,pH=6.5~7.5.结果表明,W含量质量分数高于44%的镍钨合金镀层结构为非晶态;且在此工艺下易得到钨含量在44%以上的非晶态钨合金镀层.  相似文献   

20.
方钢管混凝土柱节点的试验研究及非线性有限元分析   总被引:5,自引:1,他引:5  
聂建国  秦凯  肖岩 《工程力学》2006,23(11):99-109,115
基于方钢管混凝土柱内隔板式节点及外加强环式节点的低周反复荷载试验,在合理选择材料本构关系、破坏准则的基础上,采用通用有限元软件ANSYS对方钢管混凝土柱内隔板式节点和外加强环式节点进行了单调加载及循环加载作用下的受力性能分析。有限元分析得出的荷载-位移曲线及剪力-剪切变形曲线与试验结果吻合较好。在此基础上对外加强环式节点进行了参数分析,研究了方钢管混凝土柱的轴压比、宽厚比、核心混凝土强度及混凝土楼板高度对节点受力性能的影响,结果表明轴压比、宽厚比的影响较大。  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号