Solution‐Processed Small‐Molecule Bulk Heterojunction Ambipolar Transistors

Solution‐processed small‐molecule bulk heterojunction (BHJ) ambipolar organic thin‐film transistors are fabricated based on a combination of [2‐phenylbenzo[d,d']thieno[3,2‐b;4,5‐b']dithiophene (P‐BTDT) : 2‐(4‐n‐octylphenyl)benzo[d,d ']thieno[3,2‐b;4,5‐b']dithiophene (OP‐BTDT)] and C₆₀. Treating high electrical performance vacuum‐deposited P‐BTDT organic semiconductors with a newly developed solution‐processed organic semiconductor material, OP‐BTDT, in an optimized ratio yields a solution‐processed p‐channel organic semiconductor blend with carrier mobility as high as 0.65 cm² V^?1 s^?1. An optimized blending of P‐BTDT:OP‐BTDT with the n‐channel semiconductor, C₆₀, results in a BHJ ambipolar transistor with balanced carrier mobilities for holes and electrons of 0.03 and 0.02 cm² V^?1 s^?1, respectively. Furthermore, a complementary‐like inverter composed of two ambipolar thin‐film transistors is demonstrated, which achieves a gain of 115.     

“Regioselective Deposition” Method to Pattern Silver Electrodes Facilely and Efficiently with High Resolution: Towards All‐Solution‐Processed,High‐Performance,Bottom‐Contacted,Flexible, Polymer‐Based Electronics

“Regioselectivity deposition” method is developed to pattern silver electrodes facilely and efficiently by solution‐process with high resolution (down to 2 μm) on different substrates in A4 paper size. With the help of this method, large‐area, flexible, high‐performance polymer field‐effect transistors based on the silver electrodes and polyimide insulator are fabricated with bottom‐contact configuration by all‐solution processes. The polymer devices exhibit high performance with average field‐effect mobility over 1.0 cm² V^?1 s^?1 (the highest mobility up to 1.5 cm² V^?1 s^?1) and excellent environmental stability and flexibility, indicating the cost effectiveness of this method for practical applications in organic electronics.     

锑化铟抛光片表面粗糙度优化研究

锑化铟是中波红外探测应用较广的材料。抛光片的表面粗糙度是影响器件性能的关键指标。研究了锑化铟化学机械抛光(Chemical Mechanical Polishing, CMP)液的pH值、氧化剂比例以及抛光液流速对锑化铟抛光片表面粗糙度的影响,并结合原子力显微镜(Atomic Force Microscope, AFM)和表面轮廓仪测试对抛光片的表面粗糙度进行了表征和优化。结果表明,当pH值为8、氧化剂比例为0.75%、抛光液流速为200 L/min时,InSb晶片的表面粗糙度为1.05 nm (AFM),同时晶片的抛光宏观质量较好。     

微通道板表面羟基化工艺研究北大核心

研究了3种微通道板基底羟基化的方法,测量了羟基化处理后微通道板基底表面水接触角及通道端面的形貌变化,分析了各种方法中微通道板基底的亲水性和腐蚀情况。实验结果表明:氨水双氧水溶液对基体表面的亲水性能提升不大,NaOH溶液对基体有腐蚀作用,经食人鱼溶液处理的基体表面亲水性明显提高且无腐蚀作用。研究了微通道板在食人鱼溶液中的浸泡时间和浸泡温度对表面亲水性的影响。结果表明:随着浸泡温度的增加,微通道板表面水接触角先减小后增大,当温度为80℃时达到极小值,浸泡时间对微通道板表面的亲水性影响不大。最终确定了微通道板表面羟基化工艺:浸泡温度为80℃,静置时间为20~60 min。     

基于TOPSIS法的电子侦察目标威胁评估

对电子侦察目标进行威胁评估是有效应对电子侦察的必要环节,是战场指挥决策的重要依据。针对电子侦察的特点,确立了威胁评估的指标体系,并采用了最优解接近度排序法（TOPSIS）对电子侦察目标威胁评估进行了研究。     

一种新型单层递归神经网络解决非光滑伪凸优化问题

非光滑伪凸优化问题是一类比较特殊的非凸优化问题,常出现在各类科学与工程应用中,因此具有很大的研究价值.针对现有神经网络模型解决非光滑伪凸优化问题存在的不足,该文基于微分包含理论,提出一种新型单层递归神经网络模型.通过理论分析,证明了神经网络状态解在有限时间内收敛到可行域,且永驻其中,最终神经网络状态解收敛于原优化问题的...     

Solution‐Processed High‐Performance Tetrathienothiophene‐Based Small Molecular Blends for Ambipolar Charge Transport

Four soluble dialkylated tetrathienoacene ( TTAR) ‐based small molecular semiconductors featuring the combination of a TTAR central core, π‐conjugated spacers comprising bithiophene ( bT ) or thiophene ( T ), and with/without cyanoacrylate ( CA ) end‐capping moieties are synthesized and characterized. The molecule DbT‐TTAR exhibits a promising hole mobility up to 0.36 cm² V^?1 s^?1 due to the enhanced crystallinity of the microribbon‐like films. Binary blends of the p‐type DbT‐TTAR and the n‐type dicyanomethylene substituted dithienothiophene‐quinoid ( DTTQ‐11 ) are investigated in terms of film morphology, microstructure, and organic field‐effect transistor (OFET) performance. The data indicate that as the DbT‐TTAR content in the blend film increases, the charge transport characteristics vary from unipolar (electron‐only) to ambipolar and then back to unipolar (hole‐only). With a 1:1 weight ratio of DbT‐TTAR DTTQ‐11 in the blend, well‐defined pathways for both charge carriers are achieved and resulted in ambipolar transport with high hole and electron mobilities of 0.83 and 0.37 cm² V^?1 s^?1, respectively. This study provides a viable way for tuning microstructure and charge carrier transport in small molecules and their blends to achieve high‐performance solution‐processable OFETs.     

大功率毫米波行波管AM/PM转换特性大信号解析理论的研究

毫米波行波管是未来通信发展的重要方向,由于AM/PM转换是影响毫米波行波管通信的重要非线性特性指标,因此AM/PM转换的研究对实现毫米波行波管线性化具有重要意义．本文基于相位展开的毫米波行波管欧拉大信号注波互作用理论模型,忽略高于二阶的非线性项,建立简化的欧拉大信号注波互作用理论模型．采用逐次逼近法推导其解析解,建立二阶逼近的欧拉大信号解析理论模型．利用欧拉大信号解析理论模型推导AM/PM转换的解析解,并发现AM/PM转换的产生与电子相位直流分量的激励成正比．应用建立的欧拉大信号解析理论和AM/PM转换解析模型对一支Q波段毫米波行波管进行大信号分析,并与拉格朗日理论模型以及传统的欧拉非线性理论模型进行对比．结果表明：欧拉大信号解析解的功率、增益和相移以及AM/PM转换与拉格朗日理论在线性区和中度互作用区十分吻合,饱和增益最大误差小于8.5%．同时,相较于传统的欧拉非线性模型,欧拉大信号解析解对非线性区增益和相移非线性特性的描述更具优势,即不但具有更高的精度,而且表现出传统欧拉非线性模型无法描述的增益压缩和相位失真现象．仿真结果验证了欧拉大信号解析解和AM/PM转换解析模型在线性区到中度互作用区的正确性和有效性．该AM/PM转换解析模型为后续研究毫米波行波管AM/PM转换非线性特性的物理机制与抑制方法奠定了基础．     

Revamping SiO2 Spheres by Core–Shell Porosity Endowment to Construct a Mazelike Nanoreactor for Enhanced Catalysis in CO2 Hydrogenation to Methanol

Beyond the catalytic activity of nanocatalysts, the support with architectural design and explicit boundary could also promote the overall performance through improving the diffusion process, highlighting additional support for the morphology-dependent activity. To delineate this, herein, a novel mazelike-reactor framework, namely multi-voids mesoporous silica sphere (MVmSiO₂), is carved through a top-down approach by endowing core-shell porosity premade Stöber SiO₂ spheres. The precisely-engineered MVmSiO₂ with peripheral one-dimensional pores in the shell and interconnecting compartmented voids in the core region is simulated to prove combined hierarchical and structural superiority over its analogous counterparts. Supported with CuZn-based alloys, mazelike MVmSiO₂ nanoreactor experimentally demonstrated its expected workability in model gas-phase CO₂ hydrogenation reaction where enhanced CO₂ activity, good methanol yield, and more importantly, a prolonged stable performance are realized. While tuning the nanoreactor composition besides morphology optimization could further increase the catalytic performance, it is accentuated that the morphological architecture of support further boosts the reaction performance apart from comprehensive compositional optimization. In addition to the found morphological restraints and size-confinement effects imposed by MVmSiO₂, active sites of catalysts are also investigated by exploring the size difference of the confined CuZn alloy nanoparticles in CO₂ hydrogenation employing both in-situ experimental characterizations and density functional theory calculations.     

存在Raman效应时NLS方程的变分求解

应用变分法．讨论了Raman效应对单模光纤中类明孤子传输特性的影响,导出了类明孤子参数演化的方程组,并得出了存在Raman效应时NLS方程的孤波解。