摘要：准二维钙钛矿表现出独特的光物理性质,这使它们成为激光技术潜在进步的优秀候选材料.高性能纳秒脉冲激光和放大自发发射(ASE)是实现连续波抽运光电泵浦激光器的关键工艺.然而,在纳秒脉冲激光泵浦下发展准二维钙钛矿ASE或激光仍然存在一些困难,包括表面缺陷浓度高、俄歇复合和能量传递效率低.本文通过无添加剂的Cs^(+)阳离子掺杂策略,可以很好地控制准二维钙钛矿膜的形貌和相分布,从而解决了低n相导致的能量传递途径不足的问题.本文通过快速的能量传递过程揭示了增益性质和载流子复合.基于此,掺杂适当比例Cs^(+)阳离子的PEA_(2)(FA_(0.7)Cs_(0.3))_(2)Pb_(3)Br_(10)钙钛矿膜的净增益系数比原始钙钛矿薄膜提高了近3倍,从而将纳秒激光激发下的放大自发发射阈值降低到1/3.研究结果表明,在准二维钙钛矿中掺杂Cs^(+)可为实现高性能激光器件的相位分布设计提供见解.

摘要：The accumulation of excessive nitrate in the atmosphere not only jeopardizes human health but also disrupts the balance of the nitrogen cycle in the *** various nitrate removal technologies,electrocatalytic nitrate reduction reaction(eNO_(3)RR)has been widely studied for its advantages of being eco-friendly,easy to operate,and controllable under environmental conditions with renewable energy as the driving *** metal-based catalysts(TMCs)have been widely used in electrocatalysis due to their abundant reserves,low costs,easy-to-regulate electronic structure and considerable electrochemical *** addition,TMCs have been extensively studied in terms of the kinetics of the nitrate reduction reaction,the moderate adsorption energy of nitrogen-containing species and the active hydrogen supply *** on this,this review firstly discusses the mechanism as well as analyzes the two main reduction products(N_(2)and NH_(3))of eNO_(3)RR,and reveals the basic guidelines for the design of efficient nitrate catalysts from the perspective of the reaction ***,this review mainly focuses on the recent advances in the direction of eNO_(3RR)with four types of TMCs,Fe,Co,Ni and Cu,and unveils the interfacial modulation strategies of Fe,Co,Ni and Cu catalysts for the activity,reaction pathway and ***,reasonable suggestions and opportunities are proposed for the challenges and future development of eNO_(3)*** review provides far-reaching implications for exploring cost-effective TMCs to replace high-cost noble metal catalysts(NMCs)for eNO_(3)RR.

摘要：受电弓接触网系统为高速列车提供电能,正确评估受电弓与接触网之间的接触力(CF)对于稳定供电至关重要.CF的大小和变化范围决定了列车受流质量和安全运行.因此,快速、准确地预测CF具有重要意义.然而,通过实验收集CF数据具有挑战性,并且通过数值模拟获得及时结果并不总是可行的.在本研究中,我们提出了一种结合元启发式优化和高斯过程回归的高效的代理模型方法,来预测受电弓接触网系统接触力统计量。首先,使用有限元法(FEM)建立并验证受电弓接触网模型,用于生成训练和测试数据集.其次,利用高斯过程回归(GPR)进行对接触力的预测.将一种新开发的元启发式优化,即二元饥饿游戏搜索(HGS),应用于特征选择.为了增强BHGS的性能,嵌入了混沌机制,产生了ChaOs-HGSGPR(CHGS-GPR).最后,对CHGS-GPR的预测结果进行了评估.结果发现,所提出的CHGS-GPR对CF的平均值提供了相当准确的预测,并且可以扩展到铁路线路的初步设计、列车运行的实时评估和控制.

摘要：利用太阳能将CO_(2)光转化为化学燃料是前沿研究的热点.当前,科研的重点在于开发和优化各类光催化材料的性能.异质结构不仅用于增强无机半导体催化剂的活性,而且用于金属-有机框架(MOFs)光催化剂的构建.随着异质结技术的不断进步,新的相结概念应运而生.尽管关于无机半导体中的相结研究已取得一定进展,但是MOFs相结结构的探索尚处于起步阶段.本文中,我们成功设计并构建了一种具有卓越光催化CO_(2)还原性能的MOFs相结杂化材料.这种材料由具有高度连接性的卟啉配体(TCPP-Ni)与Zr6团簇紧密结合而成,在溶剂热反应条件下,PCN-222-Ni能够快速且均匀地成核.通过精准调控调节剂的用量,我们实现了同分异构体PCN-224-Ni在类似条件下较慢的晶体形成过程.最终制得的P@P杂化材料展现出高表面积、多孔性和卓越的结晶度.由于PCN-222-Ni和PCN-224-Ni之间的带隙匹配,光生载流子的分离和迁移得以促进,从而使P@P杂化材料展现出卓越的光还原CO_(2)性能.这一重大突破不仅标志着MOFs相结结构研究的重大进展,还拓宽了MOFs相结在CO_(2)光转化领域的应用前景.

摘要：带隙可调的钙钛矿材料在室内光伏(IPVs)领域具有广阔的应用前景.然而,与室内光相匹配的宽带隙钙钛矿通常导电性较差,缺陷密度较高,往往不利于电荷提取和传输,限制了其光伏特性.在这里,我们通过调节Br/I比,探究了不同带隙三阳离子钙钛矿的IPVs特性.研究表明,宽带隙钙钛矿能充分利用室内光,在低照度下能获得较高的开路电压,但高Br/I比的钙钛矿具有较高的缺陷密度,不利于获得高短路电流密度和填充因子.通过进一步研究不同带隙钙钛矿的结晶动力学、缺陷密度和电荷传输特性,我们发现主流观念中高效IPVs着重考虑室内光伏材料的带隙是不全面的,我们证明了通过适当降低宽带隙晶体中的Br含量可以获得室内光伏特性更优异的器件.也就是说,室内光伏晶体材料的制备需要兼顾带隙和电荷传输特性.在此工作中,平衡带隙和电荷传输的器件(Br 0.23,1.62 eV)在1035 lux的LED灯照射下取得了40.71%的最佳效率.我们的研究为高效室内光伏的设计提供了新思路.

摘要：A gallium nitride(GaN)power amplifier monolithic microwave integrated circuit(MMIC)with a wide band and high efficiency in the microwave frequency band is proposed in this *** power amplifier MMIC uses a 0.15^im GaN high electron mo-bility transistor(HEMT)*** operating frequency band of the amplifier can cover the whole K-band,i.e.,17-26.5 GHz.

摘要：Functionalized hydrogels stimulate the migration and morphogenesis of endothelial cells(ECs)and are useful substrates for wound *** present study investigates the feasibility of covalent conjugation of taurine(Tau)on a gelatin-based *** hydrogel is expected to maintain positive charged growth factors such as basic fibroblast growth factor(bFGF)and vascular endothelial growth factors(VEGFs)near ECs within the hydrogel *** gelatin was conjugated with hydroxyl phenol(Ph)and Tau moieties,and in following that Ph residues were crosslinked through a horseradish peroxidase-catalyzed *** migration characteristics of ECs were analyzed by scratch migration assay and microparticle-based cell migration *** morphology and amounts of angiopoietin 1(Ang 1),bFGF,and VEGF proteins were evaluated for encapsulated *** potential of synthesized hydrogels in wound healing was assessed by the percentage of reduction from the original wound size and histopathological analyses of rat *** incorporated Tau molecules within the hydrogel remained stable through covalent bonds during *** extended incubation,the gelatin-based hydrogel conjugated with Tau improved the migration distance and number of existing migrated *** Tau within the gelatin-based hydrogel induced high motility of ECs,accompanied by robust cytoskeleton extension and a cell subpopulation that expressed CD44 and CD31 receptors as well as enhancement of Ang 1,bFGF,and *** found that injectable Gel-Ph-Tau effectively improves wound-healing parameters.

摘要：The recent decade has witnessed an upsurge in the demands of intelligent and simplified Internet of Things(IoT)networks that provide ultra-low-power communication for numerous miniaturized *** the research community has paid great attention to wireless protocol designs for these networks,researchers are handicapped by the lack of an energy-efficient software-defined radio(SDR)platform for fast implementation and experimental *** SDRs perform well in battery-equipped systems,but fail to support miniaturized IoT devices with stringent hardware and power *** paper takes the first step toward designing an ultra-low-power SDR that satisfies the ultra-low-power or even battery-free requirements of intelligent and simplified IoT *** achieve this goal,the core technique is the effective integration ofµW-level backscatter in our SDR to sidestep power-hungry active radio frequency *** carefully develop a novel circuit design for efficient energy harvesting and power control,and devise a competent solution for eliminating the harmonic and mirror frequencies caused by backscatter *** evaluate the proposed SDR using different modulation schemes,and it achieves a high data rate of 100 kb/s with power consumption less than 200µW in the active mode and as low as 10µW in the sleep *** also conduct a case study of railway inspection using our platform,achieving 1 kb/s battery-free data delivery to the monitoring unmanned aerial vehicle at a distance of 50 m in a real-world environment,and provide two case studies on smart factories and logistic distribution to explore the application of our platform.

摘要：锌表面自然形成的非均匀氧化层(ZnO)会与电解液发生反应形成Zn_(4)(OH)_(6)SO_(4)·xH_(2)O(ZSH)副产物,导致锌负极表面非均匀沉积,从而阻碍水性锌离子电池实际应用.为了排除氧化层分布形式的影响,本文利用表面终止化学设计策略在锌负极表面制备了一层完全氧化的ZnO层,研究发现锌负极均匀分布的ZnO层会原位演化形成致密的ZSH功能层.均匀且致密的ZSH能够有效隔绝电解液的腐蚀,从而有效提高锌负极界面的稳定性.此外,ZSH(002)晶面边缘的不饱和悬空键(如-O)更容易和Zn(H_(2)O)_(6)^(2+)结构中的锌离子形成强Zn-O键,可以促进Zn(H_(2)O)_(6)^(2+)的脱溶剂化和锌离子沿边扩散,实现了高度可逆的锌沉积行为并限制了副反应.基于此,本文提出与“表面脱水-晶体通道转移”机制明显不同的“边缘脱水-沿边缘转移”锌离子输运新机制.更重要的是,基于此组装的全电池显示出高循环稳定性(超过1000次循环)和高库仑效率(99.07%),验证了其潜在的实际应用价值.

摘要：对为象从精力节省的观点的地区性的航班一样的运输飞机的推进器有成长兴趣。为在飞机上利用一个推进器推进系统的重要考虑是在推进器冲流和另外的空气动力学的表面之间的空气动力学的相互作用。使用因此是必要的一简化但是为推进器建模的相对精确的工具，与广泛地使用的致动器磁盘模型一起。这个模型的优点是它以要求的计算时间易用、便宜。另外，它也生产可接受的结果。在这研究，一个新区域化的致动器磁盘模型在一架真实四推进器的飞机上在推进器冲流干扰效果的分析被利用。结果与不活跃的致动器磁盘的盒子相比，它证明推进器冲流在电梯引起增加并且拖系数。旋转冲流引起的明显的偏航效果被注意，它应该在设计阶段被考虑。区域化的致动器磁盘模型为推进器作为一个快、相对精确的模型被评估初步的设计。