Gold序列互相关性的新证明及非最大Gold序列性质研究

Gold序列是通信中常用的伪随机序列。提供了一种Gold序列自相关性和互相关性的新的证明,不同于Kasami早先的用循环码理论的证明,本证明直接从Gold序列的定义出发,应用了有限域上迹函数性质和指数和的理论,比原证明更直观、简洁,并且直接推广到了非互素采样的情形---非最大Gold序列。随后讨论了非最大Gold序列的自相关性和互相关性,发现这时的相关函数取值为五值的,具有一定的应用价值。     

Oxygen Reduction Reaction Performance of [MTBD][beti]‐Encapsulated Nanoporous NiPt Alloy Nanoparticles

Recent advances in oxygen reduction reaction catalysis for proton exchange membrane fuel cells (PEMFCs) include i) the use of electrochemical dealloying to produce high surface area and sometimes nanoporous catalysts with a Pt‐enriched outer surface, and ii) the observation that oxygen reduction in nanoporous materials can be potentially enhanced by confinement effects, particularly if the chemical environment within the pores can bias the reaction toward completion. Here, these advances are combined by incorporating a hydrophobic, protic ionic liquid, [MTBD][beti], into the pores of high surface‐area NiPt alloy nanoporous nanoparticles (np‐NiPt/C + [MTBD][beti]). The high O₂ solubility of the [MTBD][beti], in conjunction with the confined environment within the pores, biases reactant O₂ toward the catalytic surface, consistent with an increased residence time and enhanced attempt frequencies, resulting in improved reaction kinetics. Half‐cell measurements show the np‐NiPt/C+[MTBD][beti] encapsulated catalyst to be nearly an order of magnitude more active than commercial Pt/C, a result that is directly translated into operational PEMFCs.     

化学镍金生产中的问题探讨简

文章主要探讨了化学镍金生产中所遇到的问题,如渗镀、漏镀、金面粗糙问题,结合我公司实际情况,进行的解决和改善的过程,为化学镍金生产积累了宝贵的经验,提高了我公司化学镍金的生产水平。     

Electron injection barrier and energy-level alignment at the Au/PDI8-CN2 interface via current–voltage measurements and ballistic emission microscopy

We probe electron transport across the Au/organic interface based on oriented thin films of the high-performance n-type perylene diimide semiconductor PDI8-CN₂. To this purpose, we prepared organic-on-inorganic Schottky diodes, with Au directly evaporated onto PDI8-CN₂ grown on n-Si. Temperature-dependent current–voltage characteristics and complementary ballistic electron emission microscopy studies reveal that rectification at the Au/PDI8-CN₂ interface is controlled by a spatially inhomogeneous injection barrier, that varies on a length scale of tens of nanometers according to a Gaussian distribution with mean value ∼0.94 eV and standard deviation ∼100 meV. The former gradually shifts to ∼1.04 eV on increasing PDI8-CN₂ thickness from 5 nm to 50 nm. Experimental evidences and general arguments further allow to establish the energetics at the Au/PDI8-CN₂ interface. Our work indicates injection-limited current flow in PDI8-CN₂-based devices with evaporated Au electrodes. Furthermore, it suggests chemical reactivity of PDI8-CN₂ with both Au and Si, driven by the lateral isocyano groups.     

化学镍金工艺中的镍足控制方法研究

PCB上的线路日趋精细,焊盘间距也在不断缩小。目前,PCB上的最小焊盘间距可以达到0.050 mm。而在这些小间距的焊盘上进行化学镍金处理后,镍足就会从焊盘边缘往外延伸,从而导致渗金短路。分析了镍足变化的主要影响因素,研究了铜箔毛面粗糙度,钯离子吸附和沉镍药水活性对镍足生长的不同作用,总结了减小镍足的若干措施。     

Janus‐Structured Co‐Ti3C2 MXene Quantum Dots as a Schottky Catalyst for High‐Performance Photoelectrochemical Water Oxidation

MXene materials have attracted increasing attention in electrochemical energy‐storage applications while MXene also becomes photo‐active at the quantum dot scale, making it an alternative for solar‐energy‐conversion devices. A Janus‐structured cobalt‐nanoparticle‐coupled Ti₃C₂ MXene quantum dot (Co‐MQD) Schottky catalyst with tunable cobalt‐loading content serving as a photoelectrochemical water oxidation photoanode is demonstrated. The introduction of cobalt triggers concomitant surface‐plasmon effects and acts as a water oxidation center, enabling visible‐light harvesting capability and improving surface reaction kinetics. Most importantly, due to the rectifying effects of Co‐MQD Schottky junctions, photogenerated carrier separation/injection efficiency can be fundamentally facilitated. Specifically, Co‐MQD‐48 exhibits both superior photoelectrocatalysis (2.99 mA cm^?2 at 1.23 V vs RHE) and charge migration performance (87.56%), which corresponds to 194% and 236% improvement compared with MQD. Furthermore, excellent photostability can be achieved with less than 6.6% loss for 10 h cycling reaction. This fills in gaps in MXene material research in photoelectrocatalysis and allows for the extension of MXene into optical‐related fields.     

Interfacial reactions between liquid indium and Au-deposited substrates

The morphology and growth kinetics of intermetallic compounds formed during the soldering reactions of liquid indium on Au-deposited substrates in the temperature range of 225°C and 350°C have been investigated. The results show that two types of AuIn₂ intermetallic compounds make their appearance: the continuous-wavy-crystalline type, and the floating-island type. The growth of this intermetallic compound follows the parabolic law, which indicates that the growth is diffusion-controlled. The activation energy of the reaction calculated form the Arrhenius plot of growth reaction constants is 39.42 kJ/mol. Also, the wettability of liquid indium on the surface of the gold-deposited substrate is determined from contact angle measurements. Finally, a mechanism for the interpretation of the wetting behavior of the said Au/In system is proposed, which can be ascertained by SEM observations.     

PCB镀镍金孔隙率探讨

SMT技术的兴起使有机可焊性保护涂层、化学沉镍金及电镀镍金表面处理在工业化生产中得到广泛的应用。但是这三种工艺形成的保护层较薄,不可避免的出现微孔,微孔,对表面品质有至关重要的影响,孔隙率是评价其镀层连续性的重要参数之一。本文通过试验验证的方式探讨电镀时影响镀层致密度的相关因素,总结分析出一套避免孔隙率产生的最优生产参数,为生产实际提供了理论依据。     

分级分段印制插头工艺的研发与应用

介绍了一种采用特殊的设计方法制作分级分段印制插头的工艺生产的印制插头完全没有引线残留的踪迹,对分级分段印制插头的品质做到了有效的控制,可靠性实达到品质要求,通过了实际生产应用的验证,建立了工艺规范和品质管制计划,为批量生产奠定了坚实基础。