大口径宽视场双波段扫描红外相机光学设计

通过分析计算,设计了一种大口径宽视场折射式红外相机光学系统。该系统设计用于超长线阵扫描红外相机的地面演示成像,它能同时对短波2μm—3μm、中波3μm—4.5μm双波段成像,且同时具有24°的大视场和150mm的宽口径,成像质量接近衍射极限。该系统在航天遥感领域应用广泛。     

Wide‐angle X‐ray diffraction and differential scanning calorimetry study of the crystallization of poly(ethylene naphthalate), poly(butylene naphthalate), and their copolymers

The crystallization behavior of a series of poly(ethylene‐co‐butylene naphthalate) (PEBN) random copolymers was studied. Wide‐angle X‐ray diffraction (WAXD) patterns showed that the crystallization of these copolymers could occur over the entire range of compositions. This resulted in the formation of poly(ethylene naphthalate) or poly(butylene naphthalate) crystals, depending on the composition of the copolymers. Sharp diffraction peaks were observed, except for 50/50 PEBN. Eutectic behavior was also observed. This showed isodimorphic cocrystallization of the PEBN copolymers. The variation of the enthalpy of fusion of the copolymers with the composition was estimated. The isothermal and nonisothermal crystallization kinetics were studied. The crystallization rates were found to decrease as the comonomer unit content increased. The tensile properties were also measured and were found to decrease as the butylene naphthalate content of the copolymers increased. For initially amorphous specimens, orientation was proved by WAXD patterns after drawing, but no crystalline reflections were observed. However, the fast crystallization of drawn specimens occurred when they were heated above the glass‐transition temperature. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 843–860, 2004     

一种变压器巴伦馈电的超短波紧耦合阵列天线

紧耦合阵列天线(Tightly Coupled Array, TCA)具有超宽带、低剖面、宽角扫描等特点,近年来受到国内外学者的广泛关注。然而,在甚高频(VHF)、特高频(UHF)频段TCA 由于馈电网络设计困难等原因现有的研究报道很少。为了填补这一空白,本文设计并测试了一款变压器巴伦馈电的TCA,利用变压器巴伦解决了单元平衡馈电困难问题,同时采用短路枝节抑制E面共模谐振,采用频率选择表面(FSS)匹配层改善宽角扫描阻抗匹配。实测结果表明,该天线在110~520 MHz 频带内、±40°扫描角范围内电压驻波比<2.5,和仿真结果吻合。     

Minimizing Energy Barrier in Intermediate Connection Layer for Monolithic Tandem WPeLEDs with Wide Color Gamut

Perovskite light-emitting diodes (PeLEDs) show promising prospects in the wide color gamut display owing to their ultra-narrow full width at half maximum (FWHM). However, up to now, all perovskite white LEDs integrated by standard red, green, and blue perovskite emitters, namely, monolithic white PeLEDs (WPeLEDs), have been rarely reported, owing to facing some issues, e.g., solvent incompatibility in solution technique, ion exchange, and energy transfer between different emission centers. Herein, centered on these issues, an optimal intermediate connection layer (ICL) of Po-T2T/LiF/Ag/HAT-CN/MoO₃ is adopted to successfully develop monolithic tandem multicolor PeLEDs and WPeLEDs for the first time. The multicolor PeLEDs can achieve the best external quantum efficiency of 1.8% and the highest luminance of 4844 cd m⁻². Besides, the red/green/blue (R/G/B) monolithic tandem WPeLED shows a standard white International Commission on Illumination coordinate of (0.33, 0.33) and achieves an extremely wide color gamut reaching  National Television Standards Committee of 130%. This study is the first to realize the standard R/G/B co-electroluminescence in a monolithic perovskite device and offers a feasible strategy for developing wide-color gamut perovskite displays.     

Untersuchungen an Hydriden im Bereich der Phase Ti2CO1—x Fe x (x=0–0,5)

The hydrogen absorption of the phase Ti₆₄Co_32–x Fe _x (x=0...16) and its influence on the magnetic properties have been investigated. Measurements of the vapour-pressure, wide-line NMR and magnetic susceptibility have been performed. Substitution of Co by Fe does not change the amount of absorbed hydrogen. However the reaction rate of hydriding process, the activation energy of diffusion and the magnetic quantities change upon this substitution.

     

Isomorphous inclusions of silicon, aluminum, and titanium in the germanate zeolite IPC-3

The zeolite IPC-3, isomorphous with germanate zeolite ASU-16, and its silicon, aluminum, and titanium analogs, were obtained in the presence of 1,6-diaminohexane as a template. It is possible to incorporate selectively the elements in different crystallographic positions, determined by the nature of the element, particularly its valency and its coordination number with respect to oxygen. Silicon takes tetrahedral positions in the IPC-3 lattice, Al either tetrahedral or octahedral positions, and Ti octahedral positions. Small amounts of the lithium cations facilitate tetrahedral coordination and increase the Al content in IPC-3. __________ Translated from Teoreticheskaya i éksperimental’naya Khimiya, Vol. 42, No. 4, pp. 246–251, July–August, 2006.     

一种低抖动、宽调节范围的带宽自适应CMOS锁相环

提出了一种低抖动、宽调节范围的带宽自适应CMOS锁相环.由于环路带宽可根据输入频率进行自动调节,电路性能可在整个工作频率范围内得到优化.为了进一步提高电路的抖动特性,在电荷泵电路中采用匹配技术,并在压控振荡器中应用电压-电压转换电路以减小压控振荡器的增益.芯片采用SMIC 0.35μm CMOS工艺加工.测试结果表明该锁相环电路可在200MHz～1.1GHz的输出频率范围内保持良好的抖动性能.     

空间相机共轴三反红外光学系统设计

针对空间光学系统长焦距、大视场、轻质量、小外形尺寸、大相对孔径、高成像质量的特点和发展趋势,利用ZE-MAX求解并优化空间相机共轴三反光学系统的结构参数,设计出了焦距为5 000mm,F数为10的共轴三反射光学系统.设计结果表明:该系统视场角达8°,空间频率为50 lp/mm,调制传递函数值均大于0.4,接近衍射极限,...     

小型宽带微带天线的设计研究

针对移动通信终端小型化、集成化的发展趋势,本文提出一种中心频率为7.3 GHz的小尺寸宽频带天线.基于微带天线理论及单极天线的典型结构,改变三维结构、平面形状及介质的宽度,设计出一种新型的小型天线.考虑到影响天线特性的相关因素,利用HFSS11软件进行仿真优化,结果表明,该天线大小仅为16 mm×17 mm,绝对带宽可达3.2 GHz(S11＜-10 dB),远远超过了500 MHz.为一宽带小型天线.     

机载圆锥对数螺旋天线及两种馈电方式的研究

论述了机载圆锥对数螺旋天线及其两种馈电方式的设计方法.利用FEKO软件对圆锥对数螺旋天线和两种平衡馈电方式进行了优化仿真分析.结果说明,该天线的电特性能够满足实际工程应用要求.在此基础上,研制了天线实物样机,并对该天线实物样机进行了测试.测试结果表明该天线在2.5～8GHz的工作频率范围内,方向图3dB波瓣宽度为100°左右,轴比小于3dB,驻波系数小于2.测试数据说明该天线的测试结果和仿真分析结果吻合良好,同时也说明该圆锥对数螺旋天线具有宽频带圆极化及宽频带宽波束特性,进而说明该设计方法是有效可行的,并可以推广应用.