多应用智能排风扇

设计了一种利用电压比较器对空气传感器检测到的信息进行分析、处理、在发出警报的同时继电器自动控制排风扇净化室内空气的多应用智能排风扇。     

稀土对WC颗粒增强铁基体复合涂层组织结构的影响

采用氩弧熔覆技术在45号钢表面制备一层稀土WC颗粒增强铁基体耐磨复合涂层。通过扫描电镜(SEM)、X射线衍射(XRD)和能谱仪(EDS)等测试分析手段研究了稀土的引入对复合涂层中基体组织及碳化物的影响,并与未加稀土进行了比较。结果表明:引入稀土后,一方面优化了熔覆层组织中碳化物颗粒分布,降低了熔覆层组织中碳化物颗粒的团聚、桥接,且颗粒分布均匀;另一方面改善了熔覆层的组织,细化晶粒,减弱了熔覆过程中产生的树状晶,抑制了WC颗粒的溶解和鱼骨状碳化物的生成。在熔覆层组织中碳化物颗粒相主要有三种存在形式:原始未熔WC颗粒、与基体形成的复式碳化物及在凝固过程中重新结晶的W2C(或WC)。     

一种基于复式光子晶体的多通道红外滤波器

用LiF和Si构成了一(ABBA)N型光子晶体,考虑到材料的色散关系,对其透射特性进行了研究,结果表明:在44~46μm的范围内出现了若干透射峰,透射峰的数目k与结构周期数N间满足k=N-1的关系。入射角增加,各透射峰的位置红移,长波端透射峰的红移量比短波端的稍大,当入射角θ≥45°时,短波端透射峰的透射率有所下降。两介质的几何厚度同时增加时,各透射峰的中心蓝移,对应的透射率不变;反之,其中心红移,且长波端透射峰的透射率下降。透射峰的以上特征为其实现多通道的红外滤波提供了理论指导。     

大气常压等离子射流清洗溶胶-凝胶SiO_2膜表面油脂污染物

采用大气常压等离子射流技术对溶胶-凝胶SiO2膜表面的油脂污染物进行清洗。利用分光光度计、扫描电子显微镜、红外光谱仪对溶胶-凝胶SiO2膜透过率、表面形貌、化学结构进行表征,并分析清洗前后溶胶-凝胶SiO2膜的激光损伤阈值变化。损伤阈值测试表明,1064nm波长的激光损伤阈值由污染后的16.08J/cm2上升到24.41J/cm2,与污染前24.72J/cm2的损伤阈值相当。同时还获取清洗的最佳时间为10s。清洗前后,溶胶-凝胶SiO2膜保持完好,且未产生新的有机污染物。研究结果表明:大气常压等离子射流技术可对溶胶-凝胶SiO2膜表面的油脂污染物进行有效地清洗,从而提高溶胶-凝胶SiO2膜的透过率和激光损伤阈值,为高功率激光装置的稳定运行提供保障。     

具有可控温敏相变行为的四氢呋喃-缩水甘油超支化共聚醚的合成

采用四氢呋喃(THF)和缩水甘油(glycidol)进行阳离子开环共聚,一步合成了主链中含有柔性聚四氢呋喃线型链段的温敏性超支化共聚醚.采用定量13C-NMR确定了共聚醚的超支化结构,同时计算了其支化度.利用体积排除色谱-多角度激光光散射(SEC-MALLS)对聚合物分子量及分布进行了表征.紫外-可见光光谱(UV)测试发现共聚醚水溶液透过率在最低临界溶解温度(LCST)附近呈现剧烈变化,但是其相变速率缓慢,相变平衡时间可达30 min;且聚合物溶液的相变速率和紫外光透过率变化具有温度依赖性.采用透射电镜(TEM)对相变过程观察后发现,这种缓慢相变过程是由于超支化共聚醚组装形成的胶束随温度升高发生不同程度聚集所致.     

新型城镇化对养老金收支的影响分析

随着人口老龄化的不断加重,养老金短缺状况日益严重.通过构建城镇化建设对养老金的影响机制,并采用31个省市自治区2009-2018年的统计数据,采用系统广义矩估计方法,分析新型城镇化建设对养老金收支水平的影响作用,发现城镇化对养老金收入的促进作用大于对养老金支出的影响,说明新型城镇化的建设可以有效缓解养老金缺口,实现养老金的累积效应.     

利用拉格朗日量求解黑洞背景下自由光子的运动

利用拉格朗日量求解力学问题是一种很有用的方法.本文将借助于拉格朗日量求解黑洞时空背景下自由光子的运动,在求得光子的四速度之后,借助于机械能守恒定律,考察具有不同能量的光子在黑洞背景下所允许的运动范围.随后根据力学中运动学反问题,最终得到光子的运动轨迹.     

Surface defects,stress evolution,and laser damage enhancement mechanism of fused silica under oxygen-enriched condition

Oxygen ions (O⁺) were implanted into fused silica at a fixed fluence of 1×10¹⁷ ions/cm² with different ion energies ranging from 10 keV to 60 keV. The surface roughness, optical properties, mechanical properties and laser damage performance of fused silica were investigated to understand the effect of oxygen ion implantation on laser damage resistance of fused silica. The ion implantation accompanied with sputtering effect can passivate the sub-/surface defects to reduce the surface roughness and improve the surface quality slightly. The implanted oxygen ions can combine with the structural defects (ODCs and E' centers) to reduce the defect densities and compensate the loss of oxygen in fused silica surface under laser irradiation. Furthermore, oxygen ion implantation can reduce the Si-O-Si bond angle and densify the surface structure, thus introducing compressive stress in the surface to strengthen the surface of fused silica. Therefore, the laser induced damage threshold of fused silica increases and the damage growth coefficient decreases when ion energy up to 30 keV. However, at higher ion energy, the sputtering effect is weakened and implantation becomes dominant, which leads to the surface roughness increase slightly. In addition, excessive energy aggravates the breaking of Si-O bonds. At the same time, the density of structural defects increases and the compressive stress decreases. These will degrade the laser laser-damage resistance of fused silica. The results indicate that oxygen ion implantation with appropriate ion energy is helpful to improve the damage resistance capability of fused silica components.     

Polymerization of 1-octene and determination of markhouwink constants of poly(1-octene)

The polymerization of 1-octene initiated by methylalumoxane（MAO）-activated Ni（Ⅱ）-based-α-diimine complexes[（2,6-i-Pr）₂C₆H₃-DAB（An）]NiBr₂ was investigated.Using this catalyst,poly（1-octene）s with molecular weight between 100×10³ and 400×10³ and polydispersity（M_w/M_n） between 1.3 and 1.5 were synthesized successfully by varying reaction time at room temperature.The poly（1-octene）s were amorphous polymers and could be well soluble in tetrahydrofuran（THF）.After fractional precipitation,poly（1-octene）s with narrow molecular weight distributions（M_w/M_n≤1.12） were obtained.Their weight-average molecular weights were measured by gel permeation chromatography（GPC） in conjunction with online model BI-MwA multiangle laser light scattering（MALLS）,and their intrinsic viscosities were measured by Maron’s single-point method.The k and a values in Mark-Houwink equation[η]= KM^αin THF at 40℃were 0.089 mL/g and 0.61 respectively.     

P(VdF-HFP)-ILs基多孔纤维凝胶电解液的制备

以偏氟乙烯-六氟丙烯共聚物P(VdF-HFP)为成纤聚合物,聚乙烯吡咯烷酮(PVP)为致孔聚合物,制备得到P(VdF-HFP)/PVP混合静电纺丝纤维。然后利用成纤聚合物和致孔聚合物水溶性的差异,采用超声波辅助水致相分离法,去除水溶性PVP,得到非水溶性P(VdF-HFP)骨架的多孔超细纤维。扫描电子显微镜、孔隙结构分析和显微镜相图分析等结果显示,调节混合静电纺丝纤维中PVP含量,可以得到具有不同中孔/大孔结构的多孔超细纤维膜。以P(VdF-HFP)基多孔超细纤维吸附离子液体(ILs)制备得到凝胶电解液,测试其电化学性能,结果显示由P(VdF-HFP)∶PVP=5∶3静电纺丝纤维制备的P(VdF-HFP)-ILs基多孔超细纤维凝胶电解液显示出宽电化学窗口(3.6 V)、高电导率(0.84 mS·cm~(-1))和较高的持液量(295 wt%)。