高度取向ZnO薄膜的介电和光波导特性研究

用溶胶凝胶法在不同的基片上制备了具有高度 ｃ 轴即（００２）取向的 Ｚｎ Ｏ 薄膜,研究了溶剂、稳定剂等对合成的先体溶液的影响。对薄膜的 Ｘ Ｒ Ｄ 分析表明随热处理温度的增加,ｃ 轴取向度增大,并且薄膜的晶粒尺寸在 ３００ ° Ｃ～５００ ° Ｃ 范围内增幅较大。用端面耦合的方法测量了制备在 Ｓｉ Ｏ２／ Ｓｉ（１１１）基片上薄膜的波导损耗,即随热处理温度的增加,波导损耗增大,主要来源于 Ｚｎ Ｏ 薄膜与 Ｓｉ Ｏ２ 的界面及晶粒的散射。制备在 Ｐｔ／ Ｓｉ Ｏ２／ Ｓｉ（１１１）基片上薄膜的相对介电常数为 ７～１３,电阻率则为 １．７×１０４ Ω·ｃｍ ～９．８×１０５ Ω·ｃｍ 。     

L形和Z形宽肢异形柱低周反复荷载试验研究

根据12根肢宽厚比分别为4∶1、5∶1和6∶1的宽肢L形和Z形截面柱在低周反复荷载作用下的试验研究,研究了肢宽厚比大小、箍筋配筋率对构件破坏形态以及极限荷载的影响,分析了以上因素对L形截面和Z形截面柱耗能能力和延性的不同影响,在分析试验结果的基础上提出了异形柱抗剪强度建议计算公式,最后给出了若干工程设计建议。     

Design of an ultra fast pipelined wavelength scheduler for optical burst switching

Optical Burst Switching (OBS) is an emerging technology that allows variable size data bursts to be transported directly over DWDM links without encountering O/E/O conversion. In OBS, before the transmission of a data burst, a burst header is transmitted through an electronic control path, setting up and tearing down optical paths on-the-fly. Data bursts can remain in the optical domain and pass through the OBS network transparently. Unfortunately, system performance will be greatly degraded, if burst scheduling requests cannot be processed in time. This article quantitatively studied the negative impact of control path overloading on the performance of OBS networks. Results have shown that control path overloading greatly affects the performance of the OBS routers, especially for systems with large WDM channel counts. In order to remove this performance bottleneck, we have designed and implemented an ultra fast pipelined burst scheduler that is able to process a burst request every two clock cycles, regardless of the number of WDM channels per link. The design has been implemented in Verilog HDL and synthesized to FPGAs. Circuit level simulation results confirm the correctness of the design. The circuit has achieved 100 MHz in Altera Cyclone II devices, allowing the scheduler to process a burst request every 20 ns. To the authors’ best knowledge, this is the fastest implementation of burst scheduling algorithms.     

Emerging Nonplanar van der Waals Nanoarchitectures from 2D Allotropes for Optoelectronics

The unique atomic thickness and mechanical flexibility of 2D van der Waals (vdW) materials endow them with spatial designability and constructability. It is easy to break the inherent planar construction through various spatial manipulations, thus creating vdW nanoarchitectures with nonplanar topologies. The basic properties before evolution are retained and tunable by architecture-related feature sizes, and other newly generated properties are inspiring as they are beyond the reach of 2D allotropes, bringing great competitiveness for their encouraging applications in optoelectronics. Here, these representative nonplanar vdW nanoarchitectures (i.e., nanoscrolls, nanotubes, spiral nanopyramids, spiral nanowires, nanoshells, etc.) are summarized and their structural evolution processes are elucidated. Their fascinating nascent properties based on their distinctive structural features, focusing on generally enhanced light–matter interactions and device physics, are further introduced. Finally, their opportunities and challenges for in-depth experimental exploration are prospected. It is a brand-new idea to modify the properties of 2D vdW materials from micro- and nanostructural design and evolution, offering a solid platform for twistronics, valleytronics, and integrated nanophotonics.     

Bimetal-Incorporated Black Phosphorene with Surface Electron Deficiency for Efficient Anti-Reconstruction Water Electrolysis

Surface reconstruction (SRC) is a common phenomenon and a promotion manner for Ni/Co-based precatalysts during the water splitting process. However, the catalytic surface reconstruction will in turn complicate the streamlined prediction and modeling on the catalytic activity. Hence, the rational design of anti-SRC catalysts is highly desirable, but challengeable. In this article, a series of affordable bimetal-incorporated black phosphorene (BP) catalysts are constructed by an in situ electro-exfoliation/insertion method for anti-SRC water electrolysis. It is found that the bimetals (e.g., NiFe, NiPd) are of cationic and covalent incorporation with electron-deficient state in few-layer BP. The optimized bimetal-BP structures present excellent and stable catalytic performances with low overpotentials in hydrogen evolution (HER, 53 mV, NiPd-BP) and oxygen evolution (OER, 268 mV, NiFe-BP) reactions at 10 mA cm⁻² in 1 m KOH. The anti-SRC behaviors are elucidated by in situ Raman studies during HER/OER, probably due to the balanced electron transfer pathway on Ni sites. This research opens interesting possibilities for designing the anti-SRC catalysts for efficient hydrogen production and authentic structure-activity understandings.     

Field-Induced Multiscale Polarization Configuration Transitions of Mesentropic Lead-Free Piezoceramics Achieving Giant Energy Harvesting Performance

The development of high-performance (K,Na)NbO₃ (KNN)-based lead-free piezoceramics for next-generation electronic devices is crucial for achieving environmentally sustainable society. However, despite recent improvements in piezoelectric coefficients, correlating their properties to underlying multiscale structures remains a key issue for high-performance KNN-based ceramics with complex phase boundaries. Here, this study proposes a medium-entropy strategy to design “local polymorphic distortion” in conjunction with the construction of uniformly oversize grains in the newly developed KNN solid-solution, resulting in a novel large-size hierarchical domain architecture (≈0.7 µm wide). Such a structure not only facilitates polarization rotation but also ensures a large residual polarization, which significantly improves the piezoelectricity (≈3.2 times) and obtains a giant energy harvesting performance (W_out = 2.44 mW, P_D = 35.32 µW mm⁻³, outperforming most lead-free piezoceramics). This study confirms the coexistence of multiphase through the atomic-resolution polarization features and analyzes the domain/phase transition mechanisms using in situ electric field structural characterizations, revealing that the electric field induces highly effective multiscale polarization configuration transitions based on T–O–R sequential phase transitions. This study demonstrates a new strategy for designing high-performance piezoceramics and facilitates the development of lead-free piezoceramic materials in energy harvesting applications.     

A Dilute Fluorinated Phosphate Electrolyte Enables 4.9 V-Class Potassium Ion Full Batteries

Potassium ion batteries using graphite anode and high-voltage cathodes are considered to be optimizing candidates for large-scale energy storage. However, the lack of suitable electrolytes significantly hinders the development of high-voltage potassium ion batteries. Herein, a dilute (0.8 m ) fluorinated phosphate electrolyte is proposed, which exhibits extraordinary compatibility with both graphite anode and high-voltage cathodes. The phosphate solvent, tris(2,2,2-trifluoroethyl) phosphate (TFP), has weak solvating ability, which not only allows the formation of robust anion-derived solid electrolyte interphase on graphite anode but also effectively suppresses the corrosion of Al current collector at high voltage. Meanwhile, the high oxidative stability of fluorinated TFP solvent enables stable ultrahigh-voltage (4.95 V) cycling of a potassium vanadium fluorophosphate (KVPO₄F) cathode. Using TFP-based electrolyte, the 4.9 V-class potassium ion full cell based on graphite anode and KVPO₄F cathode shows rather remarkable cycling performance with a high capacity retention of 87.2% after 200 cycles. This study provides a route to develop dilute electrolytes for high-voltage potassium ion batteries, by utilizing solvents with both weak solvating ability and high oxidative stability.     

Characterization,Cathodoluminescence, and Field‐Emission Properties of Morphology‐Tunable CdS Micro/Nanostructures

High‐quality, uniform one‐dimensional CdS micro/nanostructures with different morphologies—microrods, sub‐microwires and nanotips—are fabricated through an easy and effective thermal evaporation process. Their structural, cathodoluminescence and field‐emission properties are systematically investigated. Microrods and nanotips exhibit sharp near‐band‐edge emission and broad deep‐level emission, whereas sub‐microwires show only the deep‐level emission. A significant decrease in a deep‐level/near‐band‐edge intensity ratio is observed along a tapered nanotip towards a smaller diameter part. This behavior is understood by consideration of defect concentrations in the nanotips, as analyzed with high‐resolution transmission electron microscopy. Field‐emission measurements show that the nanotips possess the best field‐emission characteristics among all 1D CdS nanostructures reported to date, with a relatively low turn‐on field of 5.28 V µm^?1 and the highest field‐enhancement factor of 4 819. The field‐enhancement factor, turn‐on and threshold fields are discussed related to structure morphology and vacuum gap variations under emission.     

Growth of GaN Films on Si (100) Buffered with ZnO by Ion-Beam-Assisted Filtered Cathodic Vacuum Arc Technique

GaN films have been fabricated on Si (100) substrates with ZnO buffer layers by an ion-beam-assisted filtered cathodic vacuum arc (I-FCVA) technique at␣450°C. GaN films are highly (002)-oriented with a hexagonal structure examined by X-ray diffraction. The room-temperature photoluminescence spectrum of the GaN film exhibits a strong and sharp band-edge emission peak at 3.36 eV. The obtained results demonstrate the potential of the I-FCVA technique for the fabrication of high-quality GaN layers on Si substrates.     

一种应用于EEPROM的片上电荷泵电路设计

设计了一种应用于EEPROM的片内电荷泵电路系统。该电路基于Dickson电荷泵结构,通过使用稳定的参考电压驱动压控振荡电路,从而产生了占空比小于50%的精确时钟,提高了电荷泵升压速度;通过使用调压电路,限制并稳定了输出电压。HSPICE仿真结果显示:在5 V电源电压下,时钟频率高达2.085 MHz。电荷泵仅需要56.256μs就可以输出15.962 V的高压。电荷泵的电压上升时间快,性能优越。