PSPICE controlled-source models of analogous circuit for Langevin type piezoelectric transducer

The design and construction of wide-band and high efficiency acoustical projector has long been considered an art beyond the capabilities of many smaller groups. Langevin type piezoelectric transducers have been the most candidate of sonar array system applied in underwater communication. The transducers are fabricated, by bolting head mass and tail mass on both ends of stacked piezoelectric ceramic, to satisfy the multiple, conflicting design for high power transmitting capability. The aim of this research is to study the characteristics of Langevin type piezoelectric transducer that depend on different metal loading. First, the Mason equivalent circuit is used to model the segmented piezoelectric ceramic, then, the impedance network of tail and head masses is deduced by the Newton's theory. To obtain the optimal solution to a specific design formulation, PSPICE controlled-source programming techniques can be applied. A valid example of the application of PSPICE models for Langevin type transducer analysis is presented and the simulation results are in good agreement with the experimental measurements.     

Synthesis and crystal structure of a new paramagnetic complex salt of diprotonated dioxocyclam with PtCl 2− 4 and water (1:1:1)

The paramagnetic complex salt of diprotonated dioxocyclam (1,11-dihydro-5,7-dioxo-1,4,8,11tetra-azacyclotetradecane), Pt(II) tetrachloride and water has been synthesized in strongly acidic medium and identified by X-ray structure analysis. The crystals of [(C₁₀H₂₂N₄O₂)²⁺(PtCl₄)^2–]·H₂O are monoclinic, space groupP2₁ c,M _r=585.23,a=9.516(1) Å,b=11.926(1) Å,c=16.622(2) Å,=102.88(2)°,V=1839(1)ų,Z=4,D _x=2.114 g cm^–3, (MoK )=0.70930 Å,=83.1 cm^–1,F(000)=1128,T=292 K,R=0.019 for 2808 observed reflections withI > 3(I). Alternating moieties of diprotonated dioxocyclam and a PtCl _2– ⁴ anion form columns running down the c axis. Water molecules are localized in the intercolumnar space and contribute to the extensive hydrogen bond network. The macrocycle conformation is characterized by two sequences of torsional angles, corresponding to two different subunits. The shorter sequence idealized as (-sc, ap, -ac, + ac, ap, +sc) [sc( ±60°), ac( ±120°), ap(180°)], describing the C pseudosymmetric part of the molecule, is centered on a -CH₂ group between the two peptide O-C-N-H fragments. The opposite C pseudosymmetric subunit has a nearly (-sc, ac, -SC, ap)₂ conformation. Pt is square planar coordinated by four Cl atoms, Pt-Cl_ve = 2.306(8) Å. The shortest Pt ... Pt distance is 7.200(1) Å.     

超高斯光束在片状放大器中传输的特性研究

 根据非线性薛定谔方程,应用分步傅立叶算法,模拟了不同强度的入射超高斯光束在片状放大器中的传输行为。分析了超高斯光束的光束宽度参量、阶数,以及片状放大器中的自由传播空间对光传输的影响。     

准单晶硅铸锭过程中加热功率及硅料堆积孔隙率对籽晶熔化的影响

本文在考虑硅料的堆积孔隙率和熔化变形等因素的基础上,建立了基于多孔介质的堆积硅料简化模型,对光伏太阳能用准单晶硅铸锭系统的硅料熔化过程进行了数值模拟,研究了不同侧/顶加热器功率比、堆积孔隙率以及加热器总功率对籽晶熔化的影响。研究结果表明:硅料的熔化时间和籽晶的熔化比例取决于侧/顶加热器功率比,降低侧/顶加热器功率比和堆积孔隙率有助于籽晶的有效保留,但会导致籽晶的熔化界面形状发生变化,使杂质在籽晶熔化界面形状为“凹”的区域内聚集,进而影响后续晶体生长的质量;当加热器的总功率低于临界值之后,籽晶的熔化界面形状会在靠近坩埚壁面的边缘区域发生变化,导致不均匀成核的发生,不利于准单晶硅铸锭的生产。在实际工况条件下,可以根据由侧/顶加热器功率比、堆积孔隙率、加热器总功率、籽晶的熔化比例和状态绘制的等值线图对工艺参数进行合理配置。     

Infusion of Variable Chemical Structure to Tune Stacking among Metal-Organic Layers in 2D Nano MOF

Thickness of two-dimensional (2D) metal-organic frameworks (MOFs) govern their intriguing functionalities. Primarily this thickness is controlled by the stacking between the metal-organic layers (MOL). It is observed that until now such modulating factors for stacking efficiency of MOL are not well studied. Here, we report a fundamental hypothesis to comprehend regulation of stacking efficiency among MOLs as a function of chemical structure of organic ligands (dicarboxylic acids and pillar linkers). This basically involves a series of isostructural three-dimensional (3D) MOFs which contain linkers of variable chemical nature that could be depillared to generate 2D stacked MOFs of different thickness. Depending on the linkers, we encountered the formation of single MOL to stacked multiple MOLs as evidenced from atomic force microscopic and other experimental analysis. The present study gives a concrete correlation between the stacking within 2D MOFs (from monolayer to multilayers), and their 3D counter parts, which may provide a thickness tuning pathway for 2D MOFs.     

基于垂直层叠结构的多光谱彩色传感器研究

基于垂直层叠的半导体结构是多光谱彩色传感器中的新技术,它具有抗色彩失真, 高空间分辨率, 无需彩色插值和低通滤波器以及更高的光能量利用率等优点。它的基本原理是利用不同波长的光在硅材料中穿透深度的非线性分布,即：短波长的蓝光主要在表面被吸收,长波长的红光则主要在更深的位置被吸收。目前国际上研究的结构中有使用标准晶态硅工艺制作的埋入式多pn结结构和使用PECVD方法制作的非晶硅系象素结构, 其中前者利用了标准的硅工艺, 而由于后者使用了光学性能更好的非晶硅系材料, 在结构设计上具有更大的灵活性。文章在综合了国际研究文献的基础上,对其光谱机理和象素结构进行了理论与实验分析,对性能做出了比较,并提出了下一步研究的主要方向。     

Synthesis and properties of poly(acrylamide)s containing both long chain alkyl groups and phosphatidylcholine analogues in the side chains

A series of new phospholipid analogous acrylamide monomers ( 4a–e ) containing long alkyl chains as hydrophobic groups and containing phosphatidylcholine analogues as hydrophilic group were synthesized in high yields. The homopolymerizations and copolymerization ( 4b with 4e ) were carried out in the presence of a radical initiator. The structures and thermal properties of these polymers were investigated by x-ray diffraction analysis, DSC, and polarizing microscopy measurements. It has been revealed that these homopolymers ( 5b, 5c , and 5d ) which bear saturated long-hydrocarbon chains in the side chains exhibited not only orderly stacked bilayer structures at room temperature but also clear liquid crystalline behavior within a wide temperature range. The viscosity behavior of all polymers was found similar to usual polyelectrolytes in porlar solvent. The polymers obtained were also characterized by ¹H-NMR, IR, and melting point, respectively. © 1996 John Wiley & Sons, Inc.     

TOPCon太阳电池发射极Al2O3/SiNx与SiO2/Al2O3/SiNx叠层膜钝化性能的比较

本文对TOPCon电池发射结的叠层钝化膜进行了研究,对比了3种不同叠层钝化膜(SiO₂/SiN_x、Al₂O₃(1.5 nm)/SiN_x、SiO₂/Al₂O₃(1.5 nm)/SiN_x)的钝化性能。结果表明:Al₂O₃(1.5 nm)/SiN_x的钝化性能优于SiO₂/SiN_x,SiO₂/Al₂O₃(1.5 nm)/SiN_x的钝化水平最佳,隐开路电压均值可达到705 mV。基于Al₂O₃/SiN_x叠层膜研究了Al₂O₃厚度(1.5 nm、3 nm和5 nm)对钝化性能和电池转换效率的影响。当Al₂O₃厚度由1.5 nm增加到3 nm时,钝化性能得到明显提升,隐开路电压均值提高了20 mV,达到707 mV,对应电池的光电转换效率升高了0.23个百分点,与SiO₂/Al₂O₃(1.5 nm)/SiN_x叠层膜电池的转换效率持平。然而,当Al₂O₃厚度继续增加至5 nm时,隐开路电压均值保持不变。因此可以使用Al₂O₃(3 nm)/SiN_x叠层膜代替SiO₂/Al₂O₃(1.5 nm)/SiN_x叠层膜,不仅简化了电池的工艺步骤,而且降低了生产成本。     

单开关调制的PFN型层叠Blumlein线发生器

采用平板线加载的陶瓷电容型脉冲形成网络（PFN）构成了单开关调制的层叠Blumlein线发生器。采用传输线理论对短路寄生传输线的短路特性进行了理论分析,结果表明,短路寄生传输线的阻抗可以等效为耦合电感在主传输线的放电频率下产生的感抗。Pspice软件模拟表明,层叠线Blumlein线的电压叠加效率随耦合电感增加而增加。提出了一种磁环增感方法,在4级层叠Blumlein线上实现了3.1倍的脉冲电压叠加。