基于改进的迭代FFT的平面稀疏阵列综合方法

针对在原有迭代FFT稀疏阵列综合方法中,其迭代过程容易陷于死循环而必须通过多次重新随机初始化的问题,提出一种改进的迭代FFT稀疏阵列综合方法。该方法具有两层循环迭代,即在原有的迭代FFT方法基础上,增加了内层循环迭代,使得阵因子在满足副瓣约束之后再进行激励大小排序并进行阵列稀疏处理,避免了原有迭代FFT方法容易陷于局部死循环的问题。仿真结果表明,改进的方法比原有的迭代FFT方法可以获得具有更低副瓣电平的平面稀疏薄阵综合结果

Study on bio-safety for Nano-Ag/HAp as anti-bacterial materials

通信作者:史建陆Tel:(0576)85199572 E-mail: zmfjmu@ gmail．com[中文文摘]目的研究纳米银羟基磷灰石的细胞毒性。方法采用能快速、准确、敏感地评价细胞增殖率和细胞毒性的MTT比色法,以纳米羟基磷灰石为对照组,纳米银羟基磷灰石为实验组,在材料浸提液中,分别检测人牙周膜成纤维样细胞的相对增殖率。另观察细胞在扫描电镜中的形态,从而分析比较涂层表面对细胞的毒性。结果与纳米羟基磷灰石相比,纳米银羟基磷灰石涂层中的纳米银粒子直径在200～400nm时体外细胞培养显示表现出较高的细胞增殖率,细胞毒性趋于0级,显示其具有良好的生物活性。结论纳米银羟基磷灰石涂层无细胞毒性。[英文文摘]Objective To study the cytotoxicity of a Nano-Ag/HAp composite coating on titanium surface.Methods A Nano-Ag/HAp composite coating was deposited on the surface of pure titanium by electrochemical deposition.In vitro celluar responses of the PDLF to the coating were also evaluated by MTT assay.Conventional HAp coatings and commercially pure titanium were taken as control.Results The Nano-Ag/Hap bioceramic coating has good crystallization and homogeneity on nano-scale surface morphology.The PDLF culture exhibits satisfactory bioactivity．Conclusions The Nano-Ag /HAp bioceramic coating on titanium surface has promising prospects in the future clinical application

Computational fluid dynamics modeling for the second flow phenomenon of the liquid-solid flow in a polypropylene loop reactor

应用欧拉-欧拉双流体模型,考察了聚丙烯环管反应器中弯管处的流场特征。其中,采用颗粒动力学描述固相(颗粒相)黏度与压力,用多重参考坐标系模型描述轴流泵的转动。根据上述模型,模拟了环管反应器内液-固两相二次流现象,并分析了轴流泵对流场的影响。结果表明,环管反应器弯管部位存在明显的二次流现象,轴流泵会减弱流体的二次流现象。A computational fluid dynamics model based on the Eulerian-Eulerian two-fluid model was first adopted to describe the steady-state liquid-solid two-phase flow at the bending position of a polypropylene loop reactor composing of loop and axial flow pump.Next,the particle kinetics was used to describe the viscosity and pressure of the solid phase,and a multiple reference frame model was used to describe the axial flow pump.Accordingly,the model was used to study the second flow phenomenon of the liquid-solid flow in the polypropylene loop reactor and investigate the effect of the axial pump on the second flow.The results showed that an obvious second flow phenomenon could be observed in the polypropylene loop reactor,and the axial pump could weaken the above second flow phenomenon.化学工程联合国家重点实验室(清华大学)开放课题(项目编号:SKL-ChE-10A03); 国家自然科学基金资助项目(项目编号:21076171

Studies of the Synthesis of FeMo-co Modeling Compounds 1. Spectroscopic Studies of the Strategy in the Design of the Synthetic Method.

[中文文摘]本文讨论了以K_2MoS_4,FeCl_2,KOR(R=-CH_2CH_2OH或-CH_3)为基本原料,合成固氮酶铁钼辅因子(FeMo-co)模型物合成方案的设计依据。系统地考察这种体系的电子吸收光谱和激光拉曼光谱特征及其随时间的变化。实验结果支持了所提出合成方案的设计依据。[英文文摘]The strategy in the design of synthetic method for the synthesis of dicnbane-type modeling compounds of FeMo-co,with K2MoS4,FeCl2,KOR (R=-CH2CH2OH,or-CH3),and NaHS (or KHS) as the principal starting materials,has been discussed.A systematic study of the characteristic electronic absorption spectra and Laser Raman spectra of such systems,as well as the changes in spectral characteristics with time,has been made.The experimental results provide support for the strategy in the design of the synthetic method

Active-oxygen species on non-reducible rare-earth-oxide-based catalysts in oxidative coupling of methane

From supplementary in situ Raman spectroscopic studies of active-oxygen species on non-reducible rare-earth-oxide-based catalysts in the oxidative coupling of methane (OCM) and structural adaptability considerations, further support has been obtained for our proposal that there may be an active and elusive precursor (of (O) under bar (-)(2) and (O) under bar (2-)(2) adspecies), most probably (O) under bar (2-)(3) formed from reversible redox coupling of an (O) under bar (2) adspecies at an anionic vacancy with a neighboring O2- in the surface lattice. This active precursor may initiate H abstraction from CH4 and be itself converted to (O) under barH(-) + (O) under bar (-)(2), or it may abstract an electron from the oxide lattice and be converted to (O) under bar (2-)(2) + (O) under bar (-). The prospect of developing this type of OCM catalysts is discussed

The long-neglected, active surface-oxygen species, (O)under-bar(3)(2-), in oxidative coupling of methane

文献类型: Meeting Abstrac