Phonon Thermal Transport at Interfaces of a Graphene/Vertically Aligned Carbon Nanotubes/Hexagonal Boron Nitride Sandwiched Heterostructure

Molecular dynamics simulation is used to calculate the interfacial thermal resistance of a graphene/carbon nanotubes/hexagonal boron nitride(Gr/CNTs/hBN)sandwiched heterostructure,in which vertically aligned carbon nanotube(VACNT)arrays are covalently bonded to graphene and hexagonal boron nitride layers.We find that the interfacial thermal resistance(ITR)of the Gr/VACNT/hBN sandwiched heterostructure is one to two orders of magnitude smaller than the ITR of a Gr/hBN van der Waals heterostructure with the same plane size.It is observed that covalent bonding effectively enhances the phonon coupling between Gr and hBN layers,resulting in an increase in the overlap factor of phonon density of states between Gr and hBN,thus reducing the ITR of Gr and hBN.In addition,the chirality,size(diameter and length),and packing density of sandwich-layer VACNTs have an important influence on the ITR of the heterostructure.Under the same CNT diameter and length,the ITR of the sandwiched heterostructure with armchair-shaped VACNTs is higher than that of the sandwiched heterostructure with zigzag-shaped VACNTs due to the different chemical bonding of chiral CNTs with Gr and hBN.When the armchair-shaped CNT diameter increases or the length decreases,the ITR of the sandwiched heterostructure tends to decrease.Moreover,the increase in the VACNT packing density also leads to a continuous decrease in the ITR of the sandwiched heterostructure,attributed to the extremely high intrinsic thermal conductivity of CNTs and the increase of out-of-plane heat transfer channels.This work may be helpful for understanding the mechanism for ITR in multilayer vertical heterostructures,and provides theoretical guidance for a new strategy to regulate the interlayer thermal resistance of heterostructures by optimizing the design of sandwich layer thermal interface materials.

Conceptual framework of modern Zangxiang concept: a qualitative content analysis

Background:Some scholars believe modern Zangxiang concept is conceived under the thought of bio-medicine (Western medicine),which differs greatly compared to the ancient one.The view put forward stirs up great argument.Therefore,we attempt to explore whether the modern Zangxiang concept can fully reflect the specific content and structural relationship of ancient one through analyzing the frame structure of modern Zangxiang concept.Methods:The qualitative content analysis was used.The document was selected from Zangxiang Chapter in Fundamental Theory of Traditional Chinese Medicine (7th edition).The textual document was added to QSR International's NVivo qualitative data analysis software.Text was manually coded line by line according to the content described,and new categories were identified which were further divided into initial code,sub-theme,and theme.The relationships among them were explored,and a visual map of the body of knowledge (BoK) in Zangxiang theory was depicted.The similarities and differences between modern and ancient Zangxiang concepts were discussed by interpreting these themes,relationships and the visual map.Results:After analysis,there were 126 initial codes,13 sub-themes,and 4 themes including structure,function,functional outcome and the corresponding external sign.Two principal relationships,generation and mutual promotion,restriction,and inter-dependence in function were obtained.By analyzing four themes and two kinds of principal relationships,we found five different aspects between modern Zangxiang concept and ancient Zangxiang theory.Conclusion:The BoK of the modern Zangxiang concept contains four themes:structure,function,functional outcome,and the corresponding external sign.The principal relationship is referring to generation between structure and function,and between function and its corresponding outcomes.Great differences exist when talking about modern Zangxiang concept which doesn't reflect TCM characteristics and is more inclined to bio-medicine in structure from the perspective of ancient TCM theory.

A vicinal oxygen chelate protein facilitates viral infection by triggering the unfolded protein response in Nicotiana benthamiana

Vicinal oxygen chelate(VOC)proteins are members of an enzyme superfamily with dioxygenase or non-dioxygenase activities.However,the biological functions of VOC proteins in plants are poorly understood.Here,we show that a VOC in Nicotiana benthamiana(NbVOC1)facilitates viral infection.NbVOC1 was significantly induced by infection by beet necrotic yellow vein virus(BNYVV).Transient overexpression of NbVOC1 or its homolog from Beta vulgaris(BvVOC1)enhanced BNYVV infection in N.benthamiana,which required the nuclear localization of VOC1.Consistent with this result,overexpressing NbVOC1 facilitated BNYVV infection,whereas,knockdown and knockout of NbVOC1 inhibited BNYVV infection in transgenic N.benthamiana plants.NbVOC1 interacts with the basic leucine zipper transcription factors bZIP17/28,which enhances their self-interaction and DNA binding to the promoters of unfolded protein response(UPR)-related genes.We propose that bZIP17/28 directly binds to the NbVOC1 promoter and induces its transcription,forming a positive feedback loop to induce the UPR and facilitating BNYVV infection.Collectively,our results demonstrate that NbVOC1 positively regulates the UPR that enhances viral infection in plants.

通过一种新型共前驱体的方法简单合成能增强TiO_2可见光光催化活性的C修饰及Fe,N共掺杂的TiO_2材料（英文）

为了提高TiO_2的可见光光催化活性,研究者做了很多努力.晶格掺杂和表面修饰是提高TiO_2可见光光催化活性的两种重要方法,但由于这两种方法实施的条件不一样,所以很难将它们在同一个制备过程中统一起来.为了解决这个问题,我们通过邻菲罗啉与Fe2+络合形成Fe(II)-phenanthroline配合物,然后以这种配合物作为Fe,N,C的共同来源,通过水热-煅烧的方法合成Fe,N共掺杂且C表面修饰的TiO_2材料(Fe,N co-doped TiO_2/C).通过其在可见光照射下降解4-NP来评估材料的性能,同时也以XRD,FT-IR,XPS,EPR等手段对材料进行表征,结合实验结果推测了其可能的光催化机理.由可见光光催化降解动力学数据可知,Fe,N co-doped TiO_2/C表现出来的性能最佳,其反应速率常数为0.00963 min儃1,约是纯TiO_2的5.9倍,约是以三种单独来源分别引入Fe,N,C三种元素样品((Fe,N,C)-TiO_2)的5.1倍.这说明不同引入元素之间的强烈相互作用可以协同地提高TiO_2光催化能力.HRTEM图片显示Fe,N co-doped TiO_2/C中存在异质结结构,它是锐钛矿和板钛矿的混合晶相,TiO_2的这种混合晶型有利于增强其光催化性能.结合Fe,N co-doped TiO_2/C的XPS、拉曼和FT-IR数据进行分析,结果显示C元素是修饰在TiO_2晶体表面,N元素是完全掺杂到TiO_2晶格中,Fe元素大部分掺杂到晶格中,少部分修饰在晶体表面(这在Fe掺杂TiO_2的研究中较常见).另外,从XPS元素相对含量分析可知,用邻菲罗啉作为C,N的共同来源同时引入C,N,引入量比以往的报道提高了2倍左右,这表明我们报道的这种方法可以高水平地同时向TiO_2引入C和N元素,为同时高水平地向TiO_2中引入这两种元素提供了新的思路.结合EPR,时间-电流图,电化学阻抗图谱(EIS),光致发光图谱,Mott-Schottky图谱,XPS导带分析,活性自由基中间体捕获实验等多种表征的结果,我们推测Fe,N co-doped TiO_2/C的光催化机理如下:在可见光照射下,Fe,N co-doped TiO_2/C被激发而产生电子与空穴(h^+),电子与氧气反应形成O_2^-,然后O_2^-和h^+把污染物分子氧化并降解它们,而材料表面所修饰的C物质受之前所转移过来电子的保护,而不至于被强烈氧化.本研究实现了TiO_2晶格掺杂与表面修饰在同一制备过程的结合,为制备高性能无机-有机元素共掺杂,内部-外部共改性的TiO_2光催化材料提供了新的思路.

Revealing the crystallization process and realizing uniform 1.8 eV MA-based wide-bandgap mixed-halide perovskites via solution engineering

Wide-bandgap perovskites are recently drawing tremendous attention in the community for high-efficiency all-perovskite tandem solar cells.However,the formamidinium (FA^+) and methylammonium (MA^+) based wide-bandgap mixed halide perovskites suffered from high density of traps and pin-holes,respectively.Fundamental understanding on the crystallization and film formation processes are keys to overcome those challenges but not yet clearly understood.In this study,an in-situ photoluminescence technique was used to investigate the perovskite crystallization during the thermal annealing process.It is found that the crystallization of a mixed halide perovskite with bromide (Br^-) and iodine (I^-) ions following the Ostward ripening crystal growth.Interestingly,it is found that the initial nucleation reaction is quickly completed in the first few seconds,however,leaving the small crystals with inhomogeneous composition.The different aggregation affinities of such inhomogeneous small crystals provoke the formation of pin-holes during the thermal annealing process.By engineering the precursor solution to control the nucleation rate,the chemical composition of the small crystals has become homogenous.Uniform pin-hole free high Br-composited wide-bandgap MA0.9Cs0.1Pb(I0.6Br0.4)3 perovskite films with bandgap energy of 1.8 eV have been realized.The corresponding photovoltaic devices have achieved an encouraging device efficiency of 15.1% with superb photostability.

Encapsulated carbon nanotube array as a thermal interface material compatible with standard electronics packaging

Vertically aligned carbon nanotubes arrays(VACNTs)are a promising candidate for the thermal interface material(TIM)of next-generation electronic devices due to their attractive thermal and mechanical properties.However,the environment required for synthesizing VACNTs is harsh and severely incompatible with standard device packaging processes.VACNTs’extremely low in-plane thermal conductivity also limits its performance for cooling hot spots.Here,using a transfer-and-encapsulate strategy,a two-step soldering method is developed to cap both ends of the VACNTs with copper microfoils,forming a standalone Cu-VACNTs-Cu sandwich TIM and avoiding the need to directly grow VACNTs on chip die.This new TIM is fully compatible with standard packaging,with excellent flexibility and high thermal conductivities in both in-plane and through-plane directions.The mechanical compliance behavior and mechanism,which are critical for TIM applications,are investigated in depth using in situ nanoindentation.The thermal performance is further verified in an actual light emitting diode(LED)cooling experiment,demonstrating low thermal resistance,good reliability,and achieving a 17℃ temperature reduction compared with state-of-the-art commercial TIMs.This study provides a viable solution to VACNTs’longstanding problem in device integration and free-end contact resistance,bringing it much closer to application and solving the critical thermal bottleneck in next-generation electronics.

Hierarchical predictive energy management strategy for fuel cell buses entering bus stops scenario

This paper aims to answer how to use traffic information to design energy management strategies for fuel cell buses in a networked environment.For the buses entering the bus stops scenario,this paper proposes a hierarchical energy management strategy for fuel cell buses,which considers the traffic information near the bus stops.In the upper-level trajectory planning stage,the optimal SOC trajectory under various historical traffic conditions is solved through dynamic planning.The traffic information and the best SOC trajectory are mapped through BiLSTM,which can achieve fast,real-time long-term SOC reference.In the lower-level real-time predictive energy management strategy,the optimal SOC is used as the state reference to guide the predictive energy management of fuel cell buses when entering the bus stops.Simulation results show that compared with the strategy without SOC trajectory reference,the life cost of the proposed strategy is reduced by 13.8%,and the total cost is reduced by 3.61%.The SOC of the proposed strategy is closer to the DP optimal solution.

Effects of Three Commonly-used Diuretics on the Urinary Proteome

Biomarker is the measurable change associated with a physiological or pathophysiological process. Unlike blood which has mechanisms to keep the internal environment homeostatic, urine is more likely to reflect changes of the body. As a result, urine is likely to be a better biomarker source than blood. However, since the urinary proteome is affected by many factors, including diuretics, careful evaluation of those effects is necessary if urinary proteomics is used for biomarker discovery. Here, we evaluated the effects of three commonly-used diuretics （furosemide, F; hydrochlorothiazide, H; and spirolactone, S） on the urinary proteome in rats. Urine samples were collected before and after intragastric administration of diuretics at therapeutic doses and the proteomes were analyzed using label-free liquid chromatography-tandem mass spectrometry （LC-MS/MS）. Based on the criteria of P ≤ 0.05, a fold change ≥2, a spectral count ≥ 5, and false positive rate （FDR） ≤1%, 14 proteins （seven for F, five for H, and two for S） were identified by Progenesis LC-MS. The human orthologs of most of these 14 proteins are stable in the healthy human urinary proteome, and ten of them are reported as disease biomarkers. Thus, our results suggest that the effects of diuretics deserve more attention in future urinary protein biomarker studies. Moreover, the distinct effects of diuretics on the urinary proteome may provide clues to the mechanisms of diuretics.