倒锥形抗反射表面微结构的构筑

利用Langmuir-Blodgett(LB) 技术在单晶硅表面转移岛状硬脂酸单层膜图案, 通过各向异性的湿法刻蚀构筑倒锥形表面微结构. 倒锥形结构的深度及表面抗反射性能主要与刻蚀的时间有关. 这种方法结合了自组装面积大和湿法刻蚀成本低的优点, 是一种廉价、高效的制备大面积抗反射微结构的方法, 在降低光学器件和太阳能电池的成本方面具有潜在应用价值.     

8-苯胺-1-萘磺酸钛配合物的合成及催化乙烯与降冰片烯共聚合反应

合成了新型催化剂8-苯胺-1-萘磺酸钛配合物, 并应用于乙烯与降冰片烯的共聚合反应中. 分别考察了助催化剂种类[甲基铝氧烷(MAO)和三乙基铝(TEA)]、 降冰片烯浓度、 Al/Ti摩尔比、 聚合温度和聚合压力对催化活性与共聚性能的影响. 通过核磁共振、示差扫描量热和凝胶渗透色谱等对所制备的共聚物进行了表征. 结果表明, 在相同条件下, 以MAO为助催化剂时, 共聚催化活性更高, 催化剂为单活性中心, 可得到分子量分布较窄(PDI≈3)的共聚产物, 其共聚反应机理为加成聚合. 另外, 随着降冰片烯浓度的升高, 共聚物中降冰片烯单元的摩尔比呈线性上升趋势, 所得共聚物的熔点随之降低.     

Preparation,Characterization of Hydrophobic Drug in Combine Loaded Chitosan/Cyclodextrin/Trisodium Citrate Nanoparticles and in vitro Release Study

Chitosan/cyclodextrin/trisodium citrate(CS/CD/TSC) nanoparticles with ibuprofen(IBU) loaded were prepared via the ionic cross-linking method, with trisodium citrate selected as the cross-linking agent. The drug-loading capacity, particle size, zeta potential and surface morphology of the obtained nanoparticles were investigated. The results show a good drug-loading capacity. The prepared nanoparticles were spherical in shape with an average size of 293.7 nm and a zeta potential of +30.72 mV. The in vitro release studies show that the controlled release of IBU from the nanoparticles was followed. The drug release from CS/β-CD/TSC nanoparticles followed non-Fickian or anomalous diffusion.     

Fabrication,Crosslinking and in vitro Biocompatibility of a Novel Degradable Nano-structure Urethral Tubular Scaffold

A degradable poly(lactic-co-glycolic acid, LA:GA=80:20)(PLGA) urethral tubular scaffold was fabricated by electrospinning. In order to enhance the mechanical properties, the scaffold was crosslinked with glutaraldehyde. The structure and properties of the crosslinked scaffolds were investigated by the mechanical property testing, scanning electron microscopy(SEM), degradability test in vitro and 3-(4,5)-dimethylthiahiazo(-z-yl)-3,5-diphenytetrazo- liumromide(MTT). The results show that the scaffold has the nano-structure. The pore size and the porosity are suitable for cell seeding, growth and extracellular matrix production. Although influenced by the crosslinking slightly, the pore size and the porosity could still support cell proliferation and tissuse formation. The mechanical properties are remarkably increased by the crosslinking of glutaraldehyde, and it could meet the demands of a urethral stent. The scaffold could completely collapse within 70 d. The results of the biocompatibility test show that the PLGA scaffold had no cytotoxicity.     

基于热阻网络的大功率LED热管散热研究

LED结温高一直是大功率LED发展的技术瓶颈,随着单位热流密度的不断攀升,在自然冷却条件下,单纯的直肋热沉散热方式已不能满足散热要求。应用热管技术设计了热管散热系统,对该系统的传热机理和传热路线进行分析,建立该系统对应的热网络模型,对各部分热阻进行分析与计算,求得总的理论总热阻,计算得出理论结温;同时应用有限元方法对该系统进行仿真分析,对LED模块（0.025 m0.025 m0.005 m）输入30 W 电功率,得出其仿真结温稳定在58.19℃,满足结温小于65℃的要求,说明应用热管的散热系统满足设计要求。由热阻网络模型计算得出的理论结温为57.43℃,与仿真结果相差0.76℃,其误差仅为1.31％,验证了理论分析计算的正确性,对实际工程中热设计具有指导意义。     

双(环戊二烯基)二氯化锆催化合成乙烯-笼型倍半硅氧烷杂化共聚物及其结构表征

通过双(环戊二烯基)二氯化锆(Cp₂ZrCl₂)催化剂和改良的甲基铝氧烷(MMAO)助催化剂, 合成了无机-有机杂化共聚物. 研究了2种具有不同单乙烯基反应基团的笼型倍半硅氧烷(POSS)与乙烯的聚合. 对共聚产物的结构、 热力学性质、 分子量及其分布等进行了研究. 共聚单体(POSS)的插入率在0.01%~0.30%之间, 随着共聚单体在共聚物中摩尔分数的增大, 聚合物的熔点和熔解热降低. 共聚物的热重分析结果显示, 乙烯-POSS共聚物拥有更高的热分解温度以及较高的热分解残留量. 随着POSS的加入, 聚合物的分子量明显提高, 聚合物的分子量分布变宽.     

Drinfeld Twist and Symmetric Bethe Vectors of Open XYZ Chain with Non-Diagonal Boundary Terms

With the help of the Drinfeld twist or factorizing F-matrix for the eight-vertex solid-on-solid(SOS) model,we find that in the F-basis provided by the twist the two sets of pseudo-particle creation operators simultaneously take completely symmetric and polarization free form.This allows us to obtain the explicit and completely symmetric expressions of the two sets of Bethe states of the model.     

带有增益的单微环谐振器的光速控制行为

带有损耗的光波导微环谐振器在实现光速控制时存在输出脉冲能量损耗大、脉冲形状畸变严重等问题。基于带有增益和带有损耗的微环谐振器的传输特性之间的对称性,计算分析了单微环谐振器的透射率、群折射率和群速度色散等特性,分析了增益和损耗对微环谐振器输出特性影响的机制。计算了带有增益的微环谐振器的光速控制行为,并与带有损耗的微环谐振器进行对比。结果显示,带有增益的微环谐振器输出脉冲不分裂且有较大的输出强度。脉冲延迟量和超前量比损耗系统大,可用于光速控制,克服了微环带有损耗时产生的光强损耗和脉冲畸变。     

High spin band structure in 139Nd

High-spin states in 139Nd nucleus have been reinvestigated with the reaction 128Te (16O, 5n) at a beam energy of 90 MeV. The level scheme has been expanded with spin up to 47/2 h. At the low spin states,the yrast collective structure built on the vh(-1)(11/2) multiplet shows a transitional shape with γ≈32° according to calculations of the triaxial rotor-plus-particle model. Three collective oblate bands with γ～-60° at the high spin states were identified for the first time. A band crossing is observed around hw ～0.4 MeV in one oblate band based on the 25/2- level.     

气流床气化炉壁面熔渣行为模拟

本文对气流床煤气化炉内高温合成气和壁面渣层的流动与传热传质过程进行了分析,建立了渣层流动、传热传质和相变数理模型,采用VOF方法对渣层和气体之间自由界面进行追踪,采用射线追踪方法(DTRM)计算辐射换热,采用焓法计算渣层相变,熔融态渣滴在渣层表面的沉积通过源项引入.应用所建立的数学模型对实验室规模的Texaco煤气化炉进行了模拟.结果表明:气化炉壁面换热系数从上到下先增加再减少最后再增加;炉膛温度升高,固态渣层厚度减少;壁面温度升高,固态渣层厚度减少.