Probabilistic modeling of multifunction radars with autoregressive kernel mixture network

The task of modeling and analyzing intercepted multifunction radars(MFRs)pulse trains is vital for cognitive electronic reconnaissance.Existing methodologies predominantly rely on prior information or heavily constrained models,posing challenges for non-cooperative applications.This paper introduces a novel approach to model MFRs using a Bayesian network,where the conditional probability density function is approximated by an autoregressive kernel mixture network(ARKMN).Utilizing the estimated probability density function,a dynamic programming algorithm is proposed for denoising and detecting change points in the intercepted MFRs pulse trains.Simulation results affirm the proposed method's efficacy in modeling MFRs,outperforming the state-of-the-art in pulse train denoising and change point detection.

充分稳定和暴露的铜基异质结实现CO_(2)高效电还原制乙醇

二氧化碳(CO_(2))虽然被视为破坏生态环境的温室气体,但也是储量最丰富的碳资源,对其进行转化和利用将对社会环境和能源结构产生深远影响.电化学还原CO_(2)(CO_(2)RR)不仅转化效率高,而且成本较低,有望实现规模化生产.在众多催化剂中,廉价易得的铜基催化剂被认为是电化学催化还原CO_(2)生成高附加值产物的理想催化剂之一,其中铜氧化物的存在是CO_(2)RR生成高附加值产物的关键.然而,CO_(2)RR过程是在负电位下进行的,当施加电位低于‒0.1 VRHE时,铜氧化物很容易被还原为金属态铜.因此,催化剂稳定氧化态铜的能力在保持连续、高效和稳定的CO_(2)RR产多碳产物性能中至关重要.本文将简单的O_(2)等离子体处理技术与静电纺丝技术相结合,合成了多孔碳纳米纤维负载的Cu/Cu_(x)O异质结催化剂,并考察了其催化CO_(2)RR的性能.在静电纺丝过程中,Cu-ZIF-8前驱体的加入使得热处理后的原丝纤维中形成了丰富的网络贯穿多孔结构,该结构有效地实现了铜纳米颗粒的均匀分散;随后,通过O_(2)等离子体处理技术,在碳纳米纤维中构建了大量的开放介孔,为CO_(2)的吸附和反应提供了有利环境,并使Cu/Cu_(x)O异质结位点暴露于反应界面.电化学性能测试结果表明,在400 mA cm^(‒2)电流密度下,独特的Cu/Cu_(x)O异质结活性位点电催化还原CO_(2)生成乙醇的法拉第效率可达70.7%,该性能优于未经O_(2)等离子体处理的多孔铜纳米纤维.此外,高暴露的Cu/Cu_(x)O异质结活性位点显著地增加实际参与反应的活性位点数量,经计算Cu/Cu_(x)O异质结CO_(2)RR产乙醇的质量活性高达8.4 A mg^(‒1),是目前报道生产乙醇的较高质量活性.多孔碳纳米纤维衬底不仅具有协同电子输运能力,而且在CO_(2)RR测试中施加的负电压有助于维持Cu/Cu_(x)O异质结构的稳定性,使其在高电流密度下能够保持长时间的催化稳定性.此外,本文利用原位拉曼光谱和红外光谱、有限元模拟及密度泛函理论计算等方法深入研究了Cu/Cu_(x)O异质结的催化机理.原位拉曼光谱和红外光谱表征结果证实了在CO_(2)RR过程中Cu_(x)O的动态稳定状态以及关键信号*CO和C‒C键的存在;理论计算表明,Cu/Cu_(x)O异质结的存在促进了关键中间体*CO的溢流,降低了C‒C耦合过程的反应能垒,从而提高了还原产物乙醇的产率.综上,本文成功地在多孔铜纳米纤维中引入氧化物物种,并优化了纤维孔结构.其表现出了较好的电催化还原CO_(2)性能,可高选择性生成乙醇,其独特的多孔碳纤维结构充分暴露了活性位点,实现了较高的质量活性.本文所采用的催化剂组分和微观结构的调控策略为提升电催化中催化剂稳定性和催化活性提供了有益的借鉴.

Optimal operation of Internet Data Center with PV and energy storage type of UPS clusters

With the development of green data centers,a large number of Uninterruptible Power Supply(UPS)resources in Internet Data Center(IDC)are becoming idle assets owing to their low utilization rate.The revitalization of these idle UPS resources is an urgent problem that must be addressed.Based on the energy storage type of the UPS(EUPS)and using renewable sources,a solution for IDCs is proposed in this study.Subsequently,an EUPS cluster classification method based on the concept of shared mechanism niche(CSMN)was proposed to effectively solve the EUPS control problem.Accordingly,the classified EUPS aggregation unit was used to determine the optimal operation of the IDC.An IDC cost minimization optimization model was established,and the Quantum Particle Swarm Optimization(QPSO)algorithm was adopted.Finally,the economy and effectiveness of the three-tier optimization framework and model were verified through three case studies.

SiC/Pt/CdS纳米棒Z型异质结的制备及其高效光催化产氢性能

本文采用简单的化学还原辅助水热法制备了一种新型Si C/Pt/Cd SZ型异质结纳米棒,并将Pt纳米粒子锚定在Si C纳米棒与Cd S纳米粒子的界面间,诱导电子-空穴对沿着Z型迁移路径进行转移。进行一系列的表征来分析该催化体系的结构,形貌和性能。X射线衍射(XRD)和X射线光电子能谱(XPS)结果表明,成功合成了具有较好晶体结构的光催化剂。通过透射电子显微镜证明,Pt纳米颗粒生长在Si C纳米棒和Cd S纳米颗粒的界面间。UV-Vis漫反射光谱显示,所制备的Z-型异质结样品具有比原始Cd S材料更宽的光吸收范围。光致发光光谱和瞬态光电流响应进一步证明具有最佳摩尔比的Si C/Pt/Cd S纳米棒样品具有最高的电子-空穴对分离效率。通过控制Si C和Cd S的摩尔比,可以有效地调节Si C/Pt纳米棒表面Cd S的负载量,从而使得Si C/Pt/Cd S纳米棒光催化剂达到最佳性能。当Si C:Cd S=5:1(摩尔比)时可以达到最佳产氢性能,其最大析氢速率达到122.3μmol·h-1。此外,从扫描电子显微镜、XRD和XPS分析可以看出,经过三次循环测试后,Si C/Pt/Cd S光催化剂的形貌和晶体结构均基本保持不变,表明Si C/Pt/Cd S纳米复合材料在可见光下产氢时具有稳定的结构。通过选择性光沉积技术在光反应中同时进行Au纳米粒子的光还原沉积和Mn3O4纳米粒子光氧化沉积以证明电子-空穴对的Z-型转移机制。实验结果表明,Cd S导带上的电子主要参与光催化过程中的还原反应,Si C价带上的空穴更容易发生氧化反应,其中,Si C的导带上的电子将与Cd S价带上的空穴复合形成Z型传输路径。因此,提出了在光催化产氢过程中Si C/Pt/Cd S纳米棒催化体系可能的Z-型电荷迁移路径来解释产氢活性的提高。该研究为基于Si C纳米棒的Z-型光催化体系的合成提供了新的策略。基于以上分析,Si C/Pt/Cd S纳米复合材料具有高效、廉价、易于制备、结构稳定等优势,具有突出的商业应用前景。

Multiobjective optimal dispatch of microgrid based on analytic hierarchy process and quantum particle swarm optimization

Owing to the rapid development of microgrids(MGs)and growing applications of renewable energy resources,multiobjective optimal dispatch of MGs need to be studied in detail.In this study,a multiobjective optimal dispatch model is developed for a standalone MG composed of wind turbines,photovoltaics,diesel engine unit,load,and battery energy storage system.The economic cost,environmental concerns,and power supply consistency are expressed via subobjectives with varying priorities.Then,the analytic hierarchy process algorithm is employed to reasonably specify the weight coefficients of the subobjectives.The quantum particle swarm optimization algorithm is thereafter employed as a solution to achieve optimal dispatch of the MG.Finally,the validity of the proposed model and solution methodology are con firmed by case studies.This study provides refere nee for mathematical model of multiojective optimizati on of MG and can be widely used in current research field.

Effectiveness and feasibility of transradial approaches for primary percutaneous coronary intervention in patients with acute myocardial infarction

Objective： To evaluate the efficacy and feasibility of the transradial approach for primary percutaneous coronary intervention （PCI） in patients with acute myocardial infarction（AMI）. Methods： 195 patients with acute myocardial infarction were randomly divided into two groups according to the different PCI operation pathways. 105 cases were assigned to the transfemoral artery group and 90 cases to the transradial artery group. We analyzed the data from the two groups, including the achievement ratio of paracentesis, cannulation time, the time from local anesthesia to the first time balloon inflation, the time of the total procedure, achievement ratio of PCI, incidence rate of vascular complications, total duration of hospitalization, and the six-month follow-up results in both groups. Results： Our results showed that the achier ement ratio of arteriopuncture, cannulafion time and the time from local anesthesia to the first time balloon inflation in the transradial and transfemoral groups were 98.9% vs. 100%, 3.15 ± 1.56min vs. 2.86 ± 0.97 min, and 18.56 ± 4.37 min vs. 17.75 ± 3.21 min, respectively. These differences between the two groups were not statistically significant. The total operating time was 29.75 ± 4.38 rain for the transradial group and 27.89 ± 3.95 min（P 〈 0.05） for the transfemoral group. The operation achievement ratio in the transradial group was 96.7%, and 96.2% in the transfemoral group. The incidence of puncture point complications was 2.2% in the transradial group and 11.4% in the transfemoral group, and this difference was significant. The duration of hospitalization was 10.56 ± 2.85 days for the transradial group and 13.78 ± 3.15 days（P 〈 0.05） for the transfemoral group. At the six-month follow-up, the rate of survival without cardiac event was 86.1% vs. 86.4% respectively in the transradial and transfemoral groups（P 〉 0.05）. Conclusion： The transradial approach was as effective as the transfemoral approach, and there were fewer puncture point complications as well as a shorter span of hospitalization in the transradial group. PCI via the transradial approach is safe, effective and feasible in patients with AMI.

The statistical observation localized equivalent-weights particle filter in a simple nonlinear model

This paper presents an improved approach based on the equivalent-weights particle filter(EWPF)that uses the proposal density to effectively improve the traditional particle filter.The proposed approach uses historical data to calculate statistical observations instead of the future observations used in the EWPF’s proposal density and draws on the localization scheme used in the localized PF(LPF)to construct the localized EWPF.The new approach is called the statistical observation localized EWPF(LEWPF-Sobs);it uses statistical observations that are better adapted to the requirements of real-time assimilation and the localization function is used to calculate weights to reduce the effect of missing observations on the weights.This approach not only retains the advantages of the EWPF,but also improves the assimilation quality when using sparse observations.Numerical experiments performed with the Lorenz 96 model show that the statistical observation EWPF is better than the EWPF and EAKF when the model uses standard distribution observations.Comparisons of the statistical observation localized EWPF and LPF reveal the advantages of the new method,with fewer particles giving better results.In particular,the new improved filter performs better than the traditional algorithms when the observation network contains densely spaced measurements associated with model state nonlinearities.

Boosting photocatalytic hydrogen production via interfacial engineering over a Z-scheme core/shell heterojunction

Designing high efficacy photocatalysts is a promising way to improve solar fuel production efficiency.In this work,we prepared a core/shell composite of loose ZnCr layered double hydroxide nanosheets modified CdS nanorods for efficient visible light driven photocatalytic hydrogen production.The highest hydrogen production rate achieved 425.8μmol·h^(−1) without adding any noble metal cocatalyst under the visible light stimulus,which is 22.4 times that of 1 wt.%Pt-modified CdS.The corresponding apparent quantum yield is 13.9%at 420 nm.It is revealed that the synergistic actions of the interfacial redox shuttle of Cr^(3+)/Cr^(δ+)and the interfacial electric field enable the efficient separation of photoinduced charge carriers between two components via a Z-scheme energy band configuration.Meanwhile,with the hydrogen evolution contribution of Zn^(2+),a remarkable improvement in photocatalytic performance was achieved in contrast to bare CdS.This work provides an effective methodology to construct highly efficient and economically viable photocatalysts for solar H_(2)production and mechanistic study.

稳定化缺电子Cu^(δ+)活性点位电催化还原水体硝氮

电催化还原水体硝氮(electrocatalytic nitrate reduction reaction,ENRR)是极具应用潜力的绿色脱氮技术.铜基催化剂因活性高而受研究者青睐,缺电子Cu^(δ+)是其中主要活性位,但在ENRR较负工作电压下难稳定(转化为Cu^(0)).本文以市售Cu(OH)_(2)颗粒为前驱体,通过在其表面修饰1,4-萘二甲酸分子(1,4-NDC)并原位电还原活化,成功构建Cu^(δ+)-1,4-NDC催化活性点位(Cu(OH)_(2)/1,4-NDC-AT);因1,4-NDC羧基上氧的高电负性和化学稳定性,Cu^(δ+)在ENRR过程中能稳定存在.脱氮性能测试结果表明,Cu(OH)_(2)/1,4-NDC-AT在-0.40 V vs.RHE(可逆氢电极)下处理NO_(3)^(-)-N废水(22.5 mg/L),产物中NH_(3)-N选择性大于90%,比表面活性和质量活性可达1034.7 mg N/(h m^(2))和89.1 mg N/(h g_(Cu)),是相应Cu(OH)_(2)-AT的2.3和5.1倍,亦优于大部分同类催化剂.优化1,4-NDC用量和工作电压可进一步提升质量活性,在n_(1,4-NDC)/n(Cu(OH)_(2))=2.16和-0.50 V时质量活性分别提升至147.1和104.6 mg N/(h g_(Cu)).针对低浓度NO3_(3)^(-)-N废水,本文提出“ENRR+NH_(3)-N吸附去除”耦合技术,彻底消除水中氮物种;针对高浓度NO_(3)^(-)-N废水,提出“ENRR+NH_(3)-N回收”耦合技术,将水中氮以(NH_(4))_(2)SO_(4)形式回收(回收率约98.0%).

BDS空间信号异常实时检测与排除方法

北斗卫星导航系统(BeiDou navigation satellite system, BDS)空间信号异常是影响其空间信号质量评估的重要因素,检测并排除空间信号异常不仅是构建BDS空间信号故障模型的重要手段,更有利于保障BDS导航定位的完好性.传统基于事后精密星历与广播星历比对的方法存在时延较大、采样率低等问题,本文提出了一种基于Kalman滤波的载波相位平滑伪距算法,并基于BDS空间信号用户测距误差的统计特性建立了实时估计BDS空间信号用户测距误差方法,从而实时检测并排除BDS空间信号异常.基于国际全球导航卫星系统服务(international GNSS service, IGS)地面观测网1 Hz采样率数据的实验结果表明,所提出方法对BDS空间信号用户测距误差的估计精度为1.15 m,可以有效识别由卫星轨道和时钟故障引起的空间信号异常.

Selectivity regulation of CO2 electroreduction through contact interface engineering on superwetting Cu nanoarray electrodes

Electrocatalytic CO2 reduction is a promising way to mitigate the urgent energy and environmental issues, but how to increase the selectivity for desired product among multiple competi ng reaction pathways remains a bottle neck. Here, we demonstrate that engineering the gas-liquid-solid contact interface on the electrode surface could tailor the selectivity of CO2 reducti on and meanwhile suppress H2 production through regulated reacti on kin etics. Specifically, polytetrafl uoroethyle ne (PTFE) was utilized to modify a Cu nano array electrode as an example, which is able to cha nge the electrode surface from aerophobic to aerophilic state. The en riched nano-tunnels of the Cu nano array electrode can facilitate CO2 transportation and pin gaseous products on the electrode surface. The latter is believed to be the reason that boosts the Faradaic efficie ncy of liquid products by 67% and limits the H2 producti on to less than half of before. This in terface engin eeri ng strategy also lowered H2O (proton) affinity, therefore promoting CO and HCOOH production. Engineering the electrode contact interface controls the reaction kinetics and the selectivity of products, which should be inspiring for other electrochemical reactions.

Crossover from 2D metal to 3D Dirac semimetal in metallic PtTe2 films with local Rashba effect

PtTe2 and PtSe2 with trigonal structure have attracted extensive research interests since the discovery of type-II Dirac fermions in the bulk crystals. The evolution of the electronic structure from bulk 3D topological semimetal to 2D atomic thin films is an important scientific question. While a transition from 3D type-II Dirac semimetal in the bulk to 2D semiconductor in monolayer(ML) film has been reported for PtSe2, so far the evolution of electronic structure of atomically thin PtTe2 films still remains unexplored.Here we report a systematic angle-resolved photoemission spectroscopy(ARPES) study of the electronic structure of high quality PtTe2 films grown by molecular beam epitaxy with thickness from 2 ML to 6 ML.ARPES measurements show that PtTe2 films still remain metallic even down to 2 ML thickness, which is in sharp contrast to the semiconducting property of few layer PtSe2 films. Moreover, a transition from 2D metal to 3D type-II Dirac semimetal occurs at film thickness of 4–6 ML. In addition, Spin-ARPES measurements reveal helical spin textures induced by local Rashba effect in the bulk PtTe2 crystal, suggesting that similar hidden spin is also expected in few monolayer PtTe2 films. Our work reveals the transition from2D metal to 3D topological semimetal and provides new opportunities for investigating metallic 2D films with local Rashba effect.

Epitaxial growth of hyperbranched Cu/Cu2O/CuO coreshell nanowire heterostructures for lithium-ion batteries

nano 建筑学的小心的设计和期望的活跃材料的聪明的杂交能导致更先进的性质。这里，我们设计了新奇层次分叉 Cu/Cu 2 由联合一个灵巧的热水的方法和随后的控制氧化过程的 O/CuO heteronanostructure。在分支和脊梁之间的好结构和取向附生的关系被高分辨率的传播电子显微镜学调查。而且，分支生长的进化也在 Cu nanowire 表面的渐渐的氧化期间被观察了。试验性的结果建议经由二拍子的圆舞暴露进程要表现到改变湿度以便完成的表面氧化需要优化了核心壳的形成结构化的分叉的建筑学。最后，象在锂离子电池的阳极材料的如此的一个层次框架的功能的 proof-of-concept 被表明。分叉的核心壳 heterostructure 由几个工具改进电池性能：取向附生地成年的分支提供的(i) 为到卷变化的提高的电解质可接近性和高抵抗的一个高表面区域由 Li+ 置闰 / 抽取导致了；(ii ) 有它的明确的异质接面的核心壳结构增加在 lithiation 期间便于有效费用运输的接触区域；(iii ) 铜核心象提供结构的加强一样充当一个当前的收集者。

利用简易方法制备稳定的具有微纳结构的ZIF-8高效油水分离膜（英文）

在常温常压条件下,以金属网为载体,成功地制备出表面具有微纳结构的ZIF-8分离膜,该膜显示出优异的水下超疏油性能.该方法制备的ZIF-8分离膜,可以高效地分离多种油水混合物,油水分离效率高达99.99%,同时具有较高的水通量10.2×10~4L m^(-2)h^(-1),以及耐压性.进一步,通过高温处理以及多种常见有机溶剂浸泡,该膜仍然可以保持高效的油水分离性能,并且可以循环使用.由于制备方法简单,该类ZIF-8油水分离膜可以实现大面积制备,这对于油水分离的实际应用至关重要.

High-power linear-polarization burst-mode all-fibre laser and generation of frequency-adjustable microwave signal

Narrowband microwave generation with tuneable frequency is demonstrated by illuminating a photoconductive semiconductor switch(PCSS)with a burst-mode fibre laser.The whole system is composed of a high-power linearly polarized burst-mode pulsed fibre laser and a linear-state PCSS.To obtain a high-performance microwave signal,a desired envelope of burst is necessary and a pulse pre-compensation technique is adopted to avoid envelope distortion induced by the gain-saturation effect.Resulting from the technique,homogenous peak power distribution in each burst is ensured.The maximum energy of the laser burst pulse reaches 200μJ with a burst duration of 100 ns at the average power of 10 W,corresponding to a peak power of 4 kW.When the PCSS is illuminated by the burst-mode fibre laser,narrowband microwave generation with tuneable frequency(0.80-1.12 GHz)is obtained with a power up to 300 W.To the best of the authors’knowledge,it is the first demonstration of frequency-tuneable narrowband microwave generation based on a fibre laser.The high-power burst-mode fibre laser reported here has great potential for generating high-power arbitrary microwave signals for a great deal of applicable demands such as smart adaptive radar and intelligent high-power microwave systems.

Au nanowires with high aspect ratio and atomic shell of Pt-Ru alloy for enhanced methanol oxidation reaction

The methanol oxidation reaction(MOR)is the limiting half-reaction in direct methanol fuel cell(DMFC).Although Pt is the most active single-metal electrocatalyst for MOR,it is hampered by high cost and CO poisoning.Constructing a Pt or Ru monolayer on a second metal substrate by means of galvanic replacement of underpotentially deposited(UPD)Cu monolayer has been shown as an efficient catalyst design strategy for the electrocatalysis of MOR because of the presumed 100%utilization of atoms and resistance to CO poisoning.Herein,we prepared one-dimensional surface-alloyed electrocatalyst from predominantly(111)faceted Au nanowires with high aspect ratio as the substrate of under-potential deposition.The electrocatalyst comprises a core of the Au nanowire and a shell of catalytically active Pt coated by Ru.Coverage-dependent electro-catalytic activity and stability is demonstrated on the Pt/Ru submonolayers on Au wires for MOR.Among all these catalysts,Au@Pt_(ML)@Ru_(ML)exhibits the best electrocatalytic activity and poisoning tolerance to CO.This presents a viable method for the rational catalyst design for achieving high noble-metal utilization efficiency and high catalytic performance.

Yttrium chloride-modified Au/AC catalysts for acetylene hydrochlorination with improved activity and stability

The addition of yttrium chloride(YCl) to an activated carbon-supported Au catalyst(Au/AC) can markedly promote the catalytic performance of acetylene hydrochlorination to the vinyl chloride monomer(VCM), The structure and physicochemical features of the YCl-modified catalysts(Y-Au/AC)were measured by X-ray diffraction, X-ray photoelectron spectroscopy, temperature-programmed reduction, CH-temperature programmed desorption, and scanning transmission electron microscopy.The presence of YClwas found suppressing the reduction of highly oxidized Au(δ=1,3) to metallic Au~0 dependently and thus retard the agglomeration of Au nanoparticles during the reaction. In addition,the additive of YClto the Au/AC catalyst greatly inhibits the coke deposition on the catalyst surface. The optimized catalyst with an atomic ratio of Y/Au = 5(1 wt% Au loading weight) yields an 87.8% acetylene conversion and almost 100% selectivity for VCM under the reaction of GHSV(CH) = 800 hat 180 ℃.The durability test indicates that the 5 Y-1 Au/AC catalyst maintains high catalytic activity for more than2300 h at 30 hGHSV(CH) and 180 ℃, indicating great promise as a non-mercury catalyst for PVC manufacture.

Pillararene/Calixarene-based systems for battery and supercapacitor applications

Pillararene/calixarene-based functional materials have garnered significant attention for their unique topological/chemical structures and physicochemical properties,and their extended applications in electro-chemistry have given rise to a promising area of research.This review details current advance in developing electrochemical energy materials based on pillararene/calixarene systems from the viewpoint of both fundamental theoretical simulations and research on practical applications.First,we discuss the underlying mechanisms of applying pillararene/calixarene-based systems for electrochemical energy applications.Second,we summarize simulation studies on pillarquinone and calixquinone with intrinsic structures for applications in batteries.In addition,state-of-the-art applications of pillararene/calixarene-based systems in electrochemical energy storage devices such as lithium/sodium-ion batteries and supercapacitors are highlighted.The diverse roles they play and the various design strategies that have been investigated for high-performance pillararene/calixarene-based batteries are analyzed.Finally,we discuss the prospects for further developments in this emerging field.This review not only describes recent advances in pillararene/calixarene-based batteries and supercapacitors but also lays a firm groundwork for their further application in electrochemical energy engineering.

Oxygen-penetration-induced large hardness enhancement in nanoscale Nb/Ti multilayers

Nb/Ti multilayers with different modulation periods were prepared by magnetron sputtering deposition. Microstructure and mechanical properties were investigated by XRD, SEM and Nanoindentation. It turns out that hardness of samples increases with decreasing modulation wavelength （A） and then dropped at small A. Through scrutinizing other results in literature, we found that the coherent stress rather than modulus mismatch played more important role for hardness enhancement with de- creasing A of the bcc-hcp multilayers. Annealing of samples in low （or high） vacuum at 400 ~C for 30 min led to large （or medium） enhancement of hardness, while the modulated structure was still maintained. It was found that annealing in low vac- uum resulted in oxygen penetration into the multilayers as revealed by auger electron spectroscopy, but hardly changed metallic sheet resistivity. XRD results suggested that some niobium oxides were formed in Nb layers and oxygen distributed intersti- tially in Ti layers. The large hardness enhancement after annealing is mainly due to the strengthening effect from dispersive distribution of nano-scale niobium oxides and interstitial oxygen in the multilayers. In addition, interfaces between adjacent layers were more distinct after annealing which indicated good thermal stability of laminated structure.