Heat transfer of liquid metal alloy on copper plate deposited with film of different surface free energy

Liquid metal alloys(LMAs) are the potential candidates of thermal interface materials(TIMs) for electronics cooling.In the present work, buffer layers of Ag, Ti, Cu, Ni, Mo, and W were deposited on polished Cu plates by DC magnetron sputtering, the contact angles of de-ionized water and diiodomethane on the buffer layers were measured by an easy drop shape analyzer and the surface free energies(SFEs) of the buffer layers were calculated by the Owens–Wendt–Kaelble equation. Samples were prepared by sandwiching the filmed Cu plates and LMAs. The thermal properties of the samples were measured by laser flash analysis method. The SFE of the buffer layer has a strong influence on the interface heat transfer, whereas the measurement temperature has no obvious effect on the thermal properties of the samples. As the SFE of the buffer layer increases, the wettability, thermal diffusivity, and thermal conductivity are enhanced, and the thermal contact resistance is decreased.

Influence of Surface Types on the Seasonality and Inter-Model Spread of Arctic Amplification in CMIP6

A robust phenomenon termed the Arctic Amplification(AA)refers to the stronger warming taking place over the Arctic compared to the global mean.The AA can be confirmed through observations and reproduced in climate model simulations and shows significant seasonality and inter-model spread.This study focuses on the influence of surface type on the seasonality of AA and its inter-model spread by dividing the Arctic region into four surface types:ice-covered,ice-retreat,ice-free,and land.The magnitude and inter-model spread of Arctic surface warming are calculated from the difference between the abrupt-4×CO_(2)and pre-industrial experiments of 17 CMIP6 models.The change of effective thermal inertia(ETI)in response to the quadrupling of CO_(2) forcing is the leading mechanism for the seasonal energy transfer mechanism,which acts to store heat temporarily in summer and then release it in winter.The ETI change is strongest over the ice-retreat region,which is also responsible for the strongest AA among the four surface types.The lack of ETI change explains the nearly uniform warming pattern across seasons over the ice-free(ocean)region.Compared to other regions,the ice-covered region shows the maximum inter-model spread in JFM,resulting from a stronger inter-model spread in the oceanic heat storage term.However,the weaker upward surface turbulent sensible and latent heat fluxes tend to suppress the inter-model spread.The relatively small inter-model spread during summer is caused by the cancellation of the inter-model spread in ice-albedo feedback with that in the oceanic heat storage term.

Near-zero-adhesion-enabled intact wafer-scale resist-transfer printing for high-fidelity nanofabrication on arbitrary substrates

There is an urgent need for novel processes that can integrate different functional nanostructures onto specific substrates,so as to meet the fast-growing need for broad applications in nanoelectronics,nanophotonics,and fexible optoelectronics.Existing direct-lithography methods are difficult to use on fexible,nonplanar,and biocompatible surfaces.Therefore,this fabrication is usually accomplished by nanotransfer printing.However,large-scale integration of multiscale nanostructures with unconventional substrates remains challenging because fabrication yields and quality are often limited by the resolution,uniformity,adhesivity,and integrity of the nanostructures formed by direct transfer.Here,we proposed a resist-based transfer strategy enabled by near-zero adhesion,which was achieved by molecular modification to attain a critical surface energy interval.This approach enabled the intact transfer of wafer-scale,ultrathin-resist nanofilms onto arbitrary substrates with mitigated cracking and wrinkling,thereby facilitating the in situ fabrication of nanostructures for functional devices.Applying this approach,fabrication of three-dimensional-stacked multilayer structures with enhanced functionalities,nanoplasmonic structures with~10 nm resolution,and MoS2-based devices with excellent performance was demonstrated on specific substrates.These results collectively demonstrated the high stability,reliability,and throughput of our strategy for optical and electronic device applications.

Spectrofluorimetric analysis of captopril based on its obstruction effect of the nanomaterial surface energy transfer between acridine orange and gold nanoparticles

A simple and sensitive method for detection of captopril was established based on its obstructive effect on nanomaterial sur- face energy transfer （NSET）. It was found that the acridine orange （AO） could be adsorbed onto the surface of citrated-gold nanoparticles （AuNPs） through electrostatic interaction. Incidentally, the fluorescence of AO was quenched owing to the dipole-dipole interaction of NSET between AO fluorophore and the AuNPs. However, captopril could obstruct the occurrence of NSET between AO and AuNPs effectively with the formation of Au-S covalent bonds between it and the AuNPs. Consequently, AO molecules were moved away from the surface of AuNPs leading to a decline of the energy transfer efficiency. Moreover, the fluorescence of AO could be gradually restored with the addition of captopril. Under the optimal conditions, the recovered fluorescence intensity correlated linearly with the concentration of captopril in the range of 400 nmol/L-2.0μmol/L with a detection limit of 71 μmol/L. Besides, the proposed method was successfully applied for the detection of captopril in troches with the recovery of 93%-102% and the RSD lower than 2.24%. The results were in good agreement with those obtained from the HPLC method,

Ab initio investigation of excited state dual hydrogen bonding interactions and proton transfer mechanism for novel oxazoline compound

Owing to the importance of excited state dynamical relaxation, the excited state intramolecular proton transfer(ESIPT) mechanism for a novel compound containing dual hydrogen bond(abbreviated as "1-enol") is studied in this work.Using density functional theory(DFT) and time-dependent density functional theory(TDDFT) method, the experimental electronic spectra can be reproduced for 1-enol compound. We first verify the formation of dual intramolecular hydrogen bonds, and then confirm that the dual hydrogen bond should be strengthened in the first excited state. The photo-excitation process is analyzed by using frontier molecular orbital(HOMO and LUMO) for 1-enol compound. The obvious intramolecular charge transfer(ICT) provides the driving force to effectively facilitate the ESIPT process in the S1 state. Exploration of the constructed S0-state and S1-state potential energy surface(PES) reveals that only the excited state intramolecular single proton transfer occurs for 1-enol system, which makes up for the deficiencies in previous experiment.

Ultrafast Manipulation of Transient Energy Transfer Between Surface Plasmons and Resonators in Hybrid Nano-coupling System

Surface-plasmon（SP） modes triggered on metal nanostructures were strongly coupled to the local restricted electronmagnetic field supported by a Fabry-Perot（F-P） cavity. This hybrid system provided an ideal platform to study the interaction between SP and F-P resonators on nanoscales. However, the time-resolved transient energy transfer process is far from resolved. In this letter, we addressed this question by time-resolved femtosecond pump-probe technology and readily observed the transient energy transfer between SP and nanocavity resonant ener- gy. The interaction resulted in the emergence of hybrid splitting mode and the oscillating dynamics between upper and lower polariton branch（the split hybrid states）. Our work may provide a well comprehension of strong coupling between SP modes and F-P resonator modes, and lay some groundwork for many future photonic applications.

热作用下花岗岩能量演变的尺度分析

【目的】为了定量探究岩石受热作用损伤的过程。【方法】从能量角度出发,通过冷却法研究实验室尺度下不同尺寸类型花岗岩试件在空气中冷却时热物理参数演变规律,讨论花岗岩受非稳态传热全过程能量吸收、能量释放及能量耗散特性,揭示非稳态过程中能量演变规律与花岗岩试件尺寸特征的内在联系。【结果】结果表明:不同尺寸类型高温花岗岩试件空冷至室温的过程中,比热持续降低;非稳态传热能量演变过程中,同一种尺寸试件耗散能与耗散比的大小与初始高温状态呈正相关;花岗岩在非稳态传热条件一致的情况下,随试件体积的增大,用于损伤的这部分能量绝对值在增加但相对值在减小;随着试件比面的增大,用于损伤的这部分能量绝对值在减小但相对值在增大。研究结果能够丰富高温岩石力学理论研究的发展。

基于相变材料的混凝土吊罐温控数值模拟研究

为保证混凝土吊罐在垂直运输时其内部混凝土的温度,采用相变石蜡作为吊罐温控措施,通过Fluent软件探究了不同季节和不同相变石蜡厚度下混凝土温度变化情况。结果表明:在不同季节,采用相变石蜡作为吊罐温控措施,可有效控制其内部混凝土温度的波动;在冬季环境中,当相变石蜡厚度小于40 mm时,混凝土内外温度差减小有限,消峰填谷效果不理想;在夏季环境中,随着相变石蜡厚度的增加,混凝土表面最大温度的降低程度呈现先增大后减小的趋势,当相变石蜡厚度为20 mm时,混凝土表面温度达到最低。

Plasmon-enhanced FRET biosensor based on Tm^(3+)/Er^(3+)co-doped core-shell upconversion nanoparticles for ultrasensitive virus detection

Outbreaks of infectious viruses offer a formidable challenge to public healthcare systems and early detection of viruses is essential for preventing virus propagation.In this work,an ultrasensitive plasmon-enhanced fluorescence resonance energy transfer(FRET)biosensor based on core-shell upconversion nanoparticle(csUCNP)and gold nanoparticle(AuNP)for accurate detection of SARS-CoV-2 viral RNA is presented.In this biodetection assay,the Tm^(3+)/Er^(3+)co-doped csUCNP NaGdF_(4):Yb/Tm@NaYF_(4):Yb/Er acts as an energy donor and AuNP serves as an energy acceptor.The upconversion emission of Tm^(3+)and the design of the core-shell structure led to a simultaneous surface plasmon effect of AuNP.The localized surface plasmon resonance(LSPR)arising from collective oscillations of free electrons significantly enhanced FRET efficiency between Er^(3+)and AuNP.The as-prepared biosensor obtained a limit of detection(LOD)as low as 750 aM,indicating that the integration of FRET and surface plasmon into one biodetection assay significantly boosted the sensitivity of the biosensor.In addition,samples extracted from clinical samples are also utilized to validate the effectiveness of the biosensor.Therefore,this innovative plasmon-enhanced FRET biosensor based on Tm^(3+)/Er^(3+)co-doped csUCNP may pave the way for rapid and accurate biodetection applications.

IRS增强信息与能量同传赋能物联网的鲁棒公平性资源分配算法

针对6G物联网中信道误差影响与用户采集能量的公平性问题,该文在用户信干噪比受限、发射功率约束和反射相位模一约束的条件下,研究了智能反射面(IRS)辅助的信息与能量同传(SWIPT)系统中公平性采集能量最大化问题。为了解决该非凸问题,分别运用Schur-Complement和S-Procedure将无限维约束转换为有限维的矩阵线性不等式,然后利用罚函数和连续凸逼近的方法将难以求解的原问题转化为标准的凸优化问题,进而提出了一种迭代的鲁棒公平性能量采集算法。数值结果表明,所提鲁棒优化算法能够明显提升网络采集的公平性能量。

特高压交直流输电线路带电作业安全防护及碳减排效应分析

特高压(ultra high voltage,UHV)交流与直流线路同廊道运行时带电作业区域电压高、场强大,交直流混合电场比单一电场更为复杂。为确保作业人员安全,结合实际±1100 kV直流和1000 kV交流线路,建立了包含输电导线、杆塔及带电作业人员的三维计算模型,通过分析开展带电作业时人员的体表混合场强、电位转移电流及暂态能量,对作业人员安全防护进行研究。结果表明:随着作业人员不断接近直流线路,体表场强受交流线路影响越明显,最高可使作业人员体表场强增大约9%,达到1920 kV/m;交流线路的存在将导致电位转移电流增长约7%,但对暂态能量影响较小。通过对特高压线路不停电检修所减少的碳排放量进行进一步计算,验证了特高压带电作业对减少碳排放具有促进作用。

Bubble transfer on wettability-heterogeneous surfaces

Researches have investigated the formation, transportation and spreading of bubble on solid surface with specific wettability. However, bubble transfer on wettability-heterogeneous surfaces has been rarely reported, which also plays significant role in water electrolysis, heat transfer, micro-bubble collection, etc.In this work, we carefully investigate the behavior of bubble transfer from the aerophobic or aerophilic region to the superaerophilic region through fabricating the wettability-heterogenous surfaces. Surface energy was elucidated to be transformed to the kinetic energy during bubble transfer process. Theoretical analysis on the average velocity of bubble transfer was consistent with the experimental results.The influence of wettability of solid substrate, bubble volume and superaerophilic stripe width on bubble transfer are carefully investigated. Moreover, wettability-heterogeneous surfaces were explored to be applied in micro-CO_(2) bubble collection and H_(2) bubble removement in water splitting.

碰撞激活诱导的双势阱势能面可以实现9-甲基-8-氧鸟嘌呤-9-甲基腺嘌呤碱基对阳离子自由基的质子转移

8-氧鸟嘌呤(OG)是最常见的核碱基氧化损伤,它在复制过程中可以用Hoogsteen的模式与腺嘌呤(A)错误配对.0G.A碱基对不仅可以诱发G·C→T·A的颠换突变,而且由于OG的电离势和氧化电位低于天然DNA碱基更容易受到电离辐射和单电子氧化的影响,本文报道了[9MOG·9MA]^(·+)碱華对阳离子自由基的形成.和碰撞诱导解离,该碱基对利用9-甲基8-氧鸟嘌呤(9MOG)和9-甲基腺嘌呤(9MA)模拟相对应的核苷酸.实验通过电喷雾产生Cu(Ⅱ)碱基复合物继之以氧化分离产生[9MOG·9MA]^(·+),并使用导向离子束串级质谱仪检测[9MOG·9MA]^(·+)的碰撞诱导解离、通过测量在不同碰撞能量下的解离产物和反应截面,可以得出[9MOG-H]+[9MA+H]^(+)(主要解离通道)和9MOG^(·+)+9MA(次要通道)的0 K解离阈能分别为1.8和1.65 eV.使用密度泛函理论对[9MOG·9MA]^(·+)的结构计算发现其所有重要构象都发生了质子转移生成[9MOG-H]^(·)·[9MA+H]^(+).另一方面,9MOG^(·+)+9MA的解离通道却需要9MOG^(·+)9MA作为中间体.看似矛盾的结果可以用碰撞活化后反应势能面上出现的双重势阱和由此触发的激发态质子转移平衡([9MOG-H]^(·)·[9MA+H]^(+))^(*)→←(9MOG6(·+)·9MA)^(*)来解释.本文实验和理论研究揭示了这种生物学上重要的非规范碱基对如何在氧化和电离损伤时发生解离.

青藏高原北麓河地区近地层能量输送与微气象特征

利用青藏高原北麓河冻土综合试验站自动气象站2002年5月30日～6月24日观测资料,计算分析了该地区近地层的地表能量平衡、地表加热场、感热、潜热、地表反照率、动量和热量总体输送系数等特征量场的变化特征,首次得到高原北麓河地区近地层能量输送和微气象特征.

藏北高原草甸下垫面近地层能量输送及微气象特征

利用 ＧＡＭＥ／Ｔｉｂｅｔ １９９８年ＩＯＰ观测资料，分析研究藏北高原草甸下垫面近地层的地面加热场、地表能量平衡、地面阻曳系数ＣＤ及感热通量整体输送系数ＣＨ等特征，得到了一些有关藏北高原草甸下垫面近地层能量输送及微气象特征结构的新认识。

金属表面荧光增强的物理增强机制

具有特殊形貌及构型的表面(如金属薄膜)能够使位于其邻近的荧光分子的荧光信号得到增强,这种现象被称之为表面增强荧光(Surface Enhanced Fluorescence,SEF)。有关表面增强荧光效应的研究探讨已有许多报道,并先后提出了多种增强机理以试图理解和解释观测到的实验现象。本文将在总结归纳已有机理研究的基础上,从物理学的角度出发分析理解局域场增强、能量转移以及辐射衰减速率增加等理论模型,并对衬底表面与荧光分子之间的间距变化对增强效果的影响进行探讨。

石河子垦区沙漠和绿洲下垫面生态条件下能量交换特征

在古尔班通古特沙漠南部流动沙区及其以南100 km的滴灌棉田为绿洲下垫面的生态条件下,分析研究了能量输送的不同模式和日变化进程。在沙漠生态条件下,大部分净辐射用于感热通量的散失,另一部分用于向地下传输,少部分则用于潜热输送;与沙漠相比,在滴灌棉田生态条件下的绿洲能量输送的基本模式为:农田蒸散的潜热能量占绝大部分,少部分用于感热通量和土壤热通量的消耗,另一个与沙漠不同的特征是绿洲存在地表能量平衡差额。

基于Landsat TM的2001～2015年哈尔滨市地表温度变化特征分析

以哈尔滨市为例,基于2001年、2004年、2008年和2015年夏季Landsat TM 5/OLI 8遥感影像为基础数据源,采用＂单窗算法＂遥感技术手段定量反演瞬时地表温度格局,并深入分析温度特征,分区差异和重心变化。研究表明：2001～2015年研究区温度增加1.44℃,平均温年增0.10℃,3时段（2001～2004年、2005～2008年、2009～2015年）年均温分别增加0.08℃、0.09℃、0.12℃,具有加速上升趋势;最高温增加2.74℃,始终位于香坊区,最低温基本恒定,始终位于道里区;2001～2015年极高、高、极低温度分区面积增加4.92 km2、104.07 km2、87.71 km2,年均增量均具有持续增加趋势,中、低分区面积减少110.61 km2、84.94 km2,具有波动降低趋势,极高、高、中、低分区格局总体按照城区-城乡结合地区-乡村的水平梯度扩展;地表温度重心向东偏南70.58°方向移动536.90 m,其中6个市辖区迁移方向和距离差异明显,表明地表能量移动方向和温度重新分布的活跃程度不同。总体来看,研究区地表温度上升明显,分区时空变化剧烈,能量的轨迹移动过程具有折返特征。

不同腔形下盐岩储库区地表最大变形预计新方法

众多已有盐穴地下储库群地面沉降监测数据和灾变实例表明盐穴储库群地面变形预测与控制是保证储库长期安全稳性运营的关键问题之一。中国盐岩地层盐层薄、成层分布的特点加剧了库区地表发生沉陷的灾变程度,直接影响到中国盐穴地下能源储备的安全。采用Gaussian曲线表示沉降分布,结合腔体收敛函数,建立了一套有别于概率积分法的地表变形预测理论—传递函数法。在此基础上,结合中国盐岩地层特点,对比计算了相同体积下椭球形、梨形与圆柱形溶腔在发生腔体完全收敛时所导致的地表最大变形量,并利用迭加原理对不同腔群分布形式、不同腔体间距下库区地表最大沉降进行了比较。研究认为,当单腔发生完全收敛时椭圆形腔体造成的地面沉降量最小,圆柱形最大;而库群对比计算结果表明腔体中心间距的增加将导致最优腔形的变化,并非椭圆形腔体始终最优。研究成果为中国油气储库建设中库区地表变形预测、腔体形状和布局优化以及相关规范的制定等方面提供了理论依据。

蒸汽冷凝型态的表面自由能差判据

提出了蒸汽在固体表面上冷凝方式的表面自由能差判据 ,即冷凝温度下液体表面自由能与固体表面的表面自由能差大于 33.3mJ·m-2 时蒸汽在该表面上呈现滴状冷凝的必要条件 .当表面自由能差在 0与 33.3mJ·m-2范围内 ,表面强化冷凝传热的效果将取决于表面自由能差值的大小 ,差值越大 ,强化效果越明显 .这对深化表面涂层强化冷凝传热的机理以及选择传热表面涂层材料具有指导意义 .通过与文献报道实验结果的比较证实 ,该判据排除了静态接触角判据中测量温度的影响 .