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1.
采用MetalVaporVacuumArc(MEVVA)离子源的离子束合成法,往Si衬底注入剂量为3.0×10^17~1.6×10^18cm^-2的C^+制成SiC埋层,C^+离子束的引出能量为50keV,光电子能谱和红外吸收谱表明SiC埋层的结构特征明显地依赖于剂量,采用MEVVA离子源可以平均衬底温度低于400℃时得到含有立方结构的SiC埋层。  相似文献   

2.
亚毫安室温连续工作InGaAs垂直腔面发射激光器   总被引:4,自引:0,他引:4  
报道了InGaAs应变量子讲垂直腔面发射激光器(VCSEL)的室温连续工作。在MBE生长过程中利用红外高温仪测量了表观衬底热辐射振荡,实现了原位厚度监测;采用阶梯型分布布拉格反射器(DBR)及腐蚀倒台面结构,降低了器件串联电阻。对于2×3μm2的台面结构VCSEL,室温连续工作阈值电流一般为1.5mA,最低达到0.7mA,阈值电压为2.5伏,输出功率达到0.5mW,激射波长为0.94um,量子效率为12%。  相似文献   

3.
改性酚醛环氧—PTFE耐磨防蚀涂层   总被引:3,自引:0,他引:3  
介绍了一种改性酚醛环氧-PTFE耐磨防蚀涂层。这种涂层Timken试验机上于312N,2.5m/sa下耐磨寿命可达13500m/μm,摩擦系数为0.16-0.20;在スウスト试验机上3MPa、0.2m/s,干燥空气和相对湿度为50%中耐磨寿命均大于2.5×10^5周。经5%NaCl盐雾试验100h后,底材与涂层的粘结强度,抗冲击强度及  相似文献   

4.
改性酚醛环氧-PTFE耐磨防蚀涂层   总被引:2,自引:0,他引:2  
介绍了一种改性酚醛环氧-PTFE耐磨防蚀涂层。这种涂层在Timken(环-块)试验机上于312N、2.5m/s下耐磨寿命可达13500m/μm,摩擦系数为0.16~0.20;在试验机上3MPa、0.2m/s、干燥空气和相对湿度为50%中耐磨寿命均大于2.5×105周。经5%NaCl盐雾试验100h后,底材与涂层的粘结强度、抗冲击强度及柔韧性等良好,低碳钢底材无锈蚀,可广泛应用于耐磨及防蚀等场合。  相似文献   

5.
二维光纤列阵接口器件及其在光互连网络模块中的应用   总被引:2,自引:0,他引:2  
提出了一种适用于光电子集成CMOS-SEED灵巧像素光互连网络的二维光纤束列阵结构和制作方法, 采用精密加工的光纤列阵定位槽和光学监控系统, 成功地研制出32×2 的单模和多模光纤列阵I/O接口器件, 光纤列阵层内及层间位移误差均小于2μm , 角向差小于0.02°。实验中, 已将二维光纤列阵I/O接口器件用于16×16 CMOS-SEED灵巧像素光电子集成Crossbar光互连模块中, 实验结果表明, 该光纤束列阵I/O接口器件完全满足光互连系统的高精度要求。  相似文献   

6.
一氧化碳和苯乙烯交替共聚物的合成与表征   总被引:4,自引:0,他引:4  
利用乙酸钯和2,2′-联吡啶组成的催化剂体系催化一氧化碳和苯乙烯交替共聚合成出聚(1-氧代-2-苯基丙撑)(STCO)。采用IR、NMR、元素分析以及广角X光散射对该聚合物以表征。该共聚物晶体为单斜晶胞,晶胞参数为a=15.7×10-10m,b=6.17×10-10m,c=7.45×10-10m,α=90.0°,β=104.3°,γ=90.0°;晶胞体积为697.2×10-30m3;空间点群为P21/c。此外,对该共聚物热降解进行了初步研究。  相似文献   

7.
DBM-g-PE与PVC的相互作用研究EI   总被引:5,自引:1,他引:4  
采用固相接枝法制备了DBM-g-PE,用红外光谱分析证明了接枝物确实存在。PVC/CPE=100/5合金性能测定结果表明,添加5份接枝物的合金(A),缺口冲击强度、拉伸强度分别为18.2kJ/m2和53.0MPa;而添加5份PE的合金(B),其相应性能为5.1kJ/m2和33.8MPa。不加接枝物的合金(C),虽有高韧性,但拉伸强度却由53.0MPa降至50.2MPa。DSC、SEM的结果均表明,PE接枝DBM后与PVC的相互作用增强,与CPE协同作用能增韧、增强PVC,并探讨了其机理。  相似文献   

8.
在合成α,ω-双甲基丙烯酰氧基封端的聚乙二醇(BMAPEG)的基础上,通过BMAPEG与甲基丙烯酸盐(MAAM)共聚,制备了离子导电率(σ)在30℃时为4.0×10-6S/cm的单离子传导的AB交联型聚醚类固体电解质(ABCPE)。研究了影响ABCPE离子导电率的因素。结果表明,用甲基丙烯酰氯与聚乙二醇进行酯化反应可以合成所期望结构的BMAPEG。ABCPE的σ随PEG链段长度和共聚单体浓度的增加出现最大值;降低BMAPEG的双键官能度,或升高温度,σ升高。  相似文献   

9.
双马来酰亚胺作EPDM硫化胶的结构稳定剂   总被引:2,自引:0,他引:2  
用热空气老化系数、压缩永久变形和热失重(TG)表征EPDM 硫化胶的热稳定性。结果表明,未加N,N′-间苯撑双马来酰亚胺(MPBM)的EPDM 硫化胶经120 ℃×72 h 和150 ℃×72 h 热空气老化后,伸长率的老化系数分别为0.70 和0.42,而加入2 phr的MPBM 后,则分别为0.78 和0.60,120 ℃×22 h 和150 ℃×22 h 的压缩永久变形,未加MPBM 时分别是73% 和84.9% ,而加入2 phr的MPBM 后则为59.6% 和75% ,增加MPBM 用量,压缩永久变形率进一步降低。非等温热失重分析表明,起始失重温度、失重终止温度都因加入2 phrMPBM 而向高温方向移动了4 ℃左右,加入5 phrMPBM 则提高了近10 ℃,表明MPBM 不仅可作EPDM 的交联助剂,同时是老化过程中的结构稳定剂。  相似文献   

10.
介绍了波分复用(WDM)系统中功率代价的起因、测试方法和测试顺序,指出了各种起因对系统性能的影响,并提出了减小相应功率代价的方法。给出了8×2.5Gb/s×(3×150km常规单模光纤)WDM系统中第6信道和第8信道的功率代价测试结果,CH8的总功率代价为1.8dB,其中色散代价为0.8dB,ASE代价为0.9dB,串话代价为0.1dB;而CH6的总功率代价则仅有0.6dB。  相似文献   

11.
电磁铸造与普通连续铸造2024铝合金的组织性能对比   总被引:2,自引:0,他引:2  
采用电磁铸造技术和普通连续铸造技术铸造了2024变形铝合金,采用光学显微镜和扫描电镜分析了其显微组织,而且对其进行了固溶处理加人工时效。结果表明电磁铸造锭内部组织细小均匀,有高的硬度和良好的疲劳性能,电磁铸造试样的硬度大约是普通连续铸造铸坯的2倍,疲劳性能是普通连续铸造铸坯的3倍。电磁铸造铸坯还有良好的耐磨性,磨损失重量是普通连续铸造的一半。  相似文献   

12.
AlN filler was compared with crystalline silica as a filler for advanced epoxy molding compounds. Properties such as the thermal conductivity, dielectric constant, CTE, flexural strength, elastic modullus and water absorption ratio of water-resistant grade AlN-filled molding compounds according to the contents or size of AlN and the filler size distribution were evaluated. A spiral flow test was also carried out to measure the change in viscosity according to the AlN size distribution for improved fluidity. The properties of EMC that is filled with a 70 vol.% of 12 micron AlN was compared with a crystalline silica-filled EMC. Thermal conductivity was improved by 2.2 times, the dielectric constant was reduced to less than one-half, the flexural strength was improved, and the CTE was also reduced. A binary mixture of an AlN-filled (65 vol.%) EMC showed improved fluidity, thermal conductivity, dielectric constant, flexural strength and water resistance compared to a single-size AlN-filled EMC. The maximum improvement was obtained when the fraction of small particles in the binary mixture of the AlN is 0.2–0.3. The CTE of EMC was decreased by increasing the volume fraction of small particles in the binary mixture of the AlN.  相似文献   

13.
电磁铸造5182铝合金锭的组织与性能研究   总被引:5,自引:1,他引:4  
采用电磁铸造技术铸造了易拉罐用5182变形铝合金,采用光学显微镜和扫描电镜分析了其显微组织,而且对其进行了均匀化处理和对比实验。结果表明,电磁铸造锭有更加良好的内部组织和优良的力学性能,电磁铸造试样的硬度大约是普通连续铸造试样的两倍,疲劳性能是普通连续铸造铸锭的3倍,电磁铸造铸锭还有良好的耐磨性,电磁铸造锭的优良性能得宜于电磁搅拌的作用使整个铸锭获得均匀细小的晶粒组织,电磁铸造技术是一种无模铸造技术,它依靠电磁力约束液体金属成型,液体金属不与铸模接触,铸锭表面光滑如镜;相反,普通连续铸造锭表面因存在振动痕和亚表面偏析等铸造缺陷,力学性能大大降低。  相似文献   

14.
Energetically modified cement (EMC) has been produced by high intensive grinding/activation of normal portland cement (NPC) together with 20% and 50% quartz sand. EMC concretes were compared to NPC based concrete using the k-factor concept. The k-factor for concrete with w/c = 0.60–0.45 was 0.7–0.9 for 1 d and 1.1–1.3 for 28 d compressive strength. k > 1 for both capillary suction, porosity, vapor diffusion and chloride permeability. For carbonation resistance k was ≈0.55.Microstructure of EMC paste with 50% quartz sand and w/c = 0.40 showed that the quartz was extensively ground and formed agglomerates with cement having a high inner surface. The degree of hydration of the cement in EMC was as high as 71% after 1 d compared to 45% for untreated blend. Refined pore size distribution of EMC versus the blend means that even for equal hydration at higher ages EMC will perform better.  相似文献   

15.
对单向形状记忆聚合物复合材料(EMC)层合板在其基体玻璃化转变温度(Tg)之上的弯曲行为进行了研究。首先介绍了EMC层合板多约束弯曲变形实验, 并依据纤维微屈曲变形特征建立其形函数; 然后分析得出弯曲层合板的各分应变能及由其组成的总应变能; 在此基础上, 依据虚功原理, 通过总应变能推导出外力偶矩与曲率、 等效弯曲应变之间的非线性关系式。结果表明: 在EMC板的弯曲过程中, 中性层很快接近板的拉伸表面, 且中性层位置及板的弯曲行为对板的面内剪切模量非常敏感; 在板的初始弯曲阶段, 弯矩与曲率遵循传统单向板的线弹性弯曲理论; 而后随着曲率的增加, 弯矩与曲率关系遵循本研究所提出的非线性关系, 所得理论结果与EMC层合板的四点纯弯曲实验现象较为吻合。   相似文献   

16.
Relatively few studies have been performed on the equilibrium moisture content (EMC) of wood under conditions of elevated temperature and pressure. Eight studies indicated that EMC near saturation decreased between 100 and 150 °C, whilst five studies indicated that EMC increased. The aim of this study was to identify the likely source of the disagreement using radiata pine (Pinus radiata D. Don) sapwood which was conditioned to a moisture content of around 3 % and then exposed for 1 h at 150 °C and relative humidities of either 50, 70 or 90 %. Mean values of EMC, obtained through in situ gravimetric analyses, were 5.7, 7.6 and 12.6 % with 95 % confidence intervals of the order of 1 %. In two further experiments, the humidity was allowed to rise briefly above 90 % and the moisture content after 1 h was found to be >30 % as in the five studies that indicated EMC increased above 100 °C. The high moisture contents were attributed to condensation of liquid water on the specimen with subsequent evaporation at a rate that was too slow for the moisture content to reach equilibrium before it was measured. Reliable EMC data at elevated temperatures require (1) tight process control of experimental conditions with minimal standard error, (2) specimens with low initial moisture content to avoid unwanted wood mass loss over time, (3) a relative humidity upper limit that avoids drift above 95 %, and (4) extrapolation of data to humidity approaching 100 %.  相似文献   

17.
集成电路封装用环氧模塑料的绿色阻燃   总被引:1,自引:0,他引:1  
合成了三聚氰胺改性含氮酚醛树脂,以邻甲酚醛环氧树脂为基体树脂,以自制的改性酚醛树脂为固化剂和阻燃剂,对集成电路封装用环氧模塑料绿色阻燃配方及工艺进行了研究。结果表明自制的改性酚醛树脂固化能力好,阻燃效果好。  相似文献   

18.
Granular magnetic ultrathinthin multilayer films Fe/ FeO on Al substrates, modelling of a 1 D granulare thin film for EMC applications Hematite ferrite thin films in granular structures have attracted much attention as materials with unique proper ties. One of these properties is enhanced microwave absorption for a good EMC application. This gives a possibility to absorption electro magnetic covers ( EMC ) of cable application with ultrathin thickness and granular structure. The Electromagnetic Compatibility absorption of granular Ferrite polycristalline sample is 6 ‐ 7 dB in the GH z ‐ range.  相似文献   

19.
The aim of the present research is to check the capability of the equivalent material concept (EMC) combined with the J‐integral failure criterion, called EMC‐J criterion, in predicting the load‐carrying capacity (LCC) of U‐notched ductile aluminium plates subjected to tension by considering the 2 moderate and large‐scale yielding regimes. For this purpose, first, a set of experimental results on LCC of 2 groups of thin U‐notched rectangular plates made of Al 7075‐T6 and Al 6061‐T6 are gathered from the recent literature. Then, because the Al 7075‐T6 and Al 6061‐T6 plates have ductile behaviour, EMC is employed to avoid performing elastic‐plastic failure analysis for LCC predictions. Up to now, different failure models in the context of the linear‐elastic notch fracture mechanics have been successfully utilized in combination with EMC for ductile failure prediction of notched members. However, this is the first time in this research that J‐integral, as a well‐known brittle failure criterion, is linked to EMC for predicting LCC of the U‐notched rectangular aluminium plates. Finally, it is shown that EMC‐J criterion can predict well the experimental results of tensile LCC.  相似文献   

20.
合同能源管理在我国供热空调系统中的应用前景分析   总被引:1,自引:0,他引:1  
针对我国的能源形势,分析了供热空调系统的节能潜力,介绍了具有很好发展前景的合同能源管理概念、方法和步骤,以及在我国实施过程中出现的问题及对策.以实际空调和供热工程的案例对合同能源管理的效益进行了分析,结果表明,合同能源管理是一种业主和合同能源管理公司双赢的模式,在我国供热和空调行业有广阔的应用前景.  相似文献   

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