Balloon-occluded retrograde transvenous obliteration for treatment of congenital intrahepatic portosystemic venous shunt:A case report

Congenital intrahepatic portosystemic venous shunt(CPSVS), a rare vascular malformation, has been described in both children and adults and can lead to severe neurophysiological complications. However, a standard therapeutic protocol for CPSVS has not been elucidated. With the advantage of minimally invasive techniques,transcatheter embolization has been used to treat CPSVS. The condition is challenging to manage, especially in patients with large or multiple shunts, through which rapid blood flow can cause ectopic embolism. Here, we describe a case of CPSVS with a large shunt that was successfully treated with balloon-occluded retrograde transvenous obliteration with interlocking detachable coils.

虫草素纳米乳液制备及对皮肤光老化修复机制研究

将虫草素(cordycepin)作为功效成分制作成纳米乳液,并研究了虫草素纳米乳液配方工艺、质量初步评价和对皮肤光老化修复机制。通过绘制伪三元相图,确定虫草素纳米乳液配方,考察纳米乳粒径、黏度、稳定性,以及虫草素稳定性。利用紫外线照射新西兰兔子皮肤,检测皮肤中的超氧化物歧化酶(SOD)、谷胱甘肽(GSH)、过氧化氢酶(CAT)活力和丙二醛(MDA)的含量。结果表明,乳化剂和助乳化剂质量比(Km)为2∶1时得到的纳米乳液较稳定,虫草素纳米乳平均直径为374 nm,黏度为(9.33±0.14)mPa·s,具有良好的离心稳定性、稀释稳定性、长期稳定性和温度稳定性;虫草素1~8个月维持在(12.006±0.025)mg/g,RSD在1%以内,第9个月开始减少;使用虫草素纳米乳液实验组4的SOD、CAT活性和GSH含量稍低于对照组,显著高于实验组1、2和3(P<0.01),对照组和实验组4的MDA含量均明显低于实验组1、2和3(P<0.01)。虫草素纳米乳液具有较好的稳定性、黏度和粒径大小,可以有效缓解紫外线照射引起的皮肤衰老。

Waverider configurations derived from general conical flowfields

A method based on the computational fluid dynamics （CFD） is presented for a flexible waverider＇s design. The generating bodies of this method could be any cones. In addition, either the leading edge or the profile of the scramjet＇s inlet is used as the waverider＇s definition curve, parameterized by the quadric function, the sigmoid function or the B-spline function. Furthermore, several numerical examples are carried out to validate the method and the relevant codes. The CFD results of the configurations show that all the designs are successful. Moreover, primary suggestions are proposed for practical design by comparing the geometrical and aerodynamic performances of the conederived waveriders at Mach 6.

Influences of affiliated components and train length on the train wind

The induced airfl w from passing trains,which is recognized as train wind,usually has adverse impacts on people in the surroundings,i.e.,the aerodynamic forces generated by a high-speed train＇s wind may act on the human body and endanger the safety of pedestrians or roadside workers.In this paper,an improved delayed detached eddy simulation（IDDES） method is used to study train wind.The effects of the affiliate components and train length on train wind are analyzed.The results indicate that the aff liated components and train length have no effect on train wind in the area in front of the leading nose.In the downstream and wake regions,the longitudinal train wind becomes stronger as the length of the train increases,while the transverse train wind is not affected.The presence of affiliate components strengthens the train wind in the near fiel of the train because of strong fl w solid interactions but has limited effects on train wind in the far field.

Frame-invariance in finite element formulations of geometrically exact rods

This article is concerned with finite element implementations of the three- dimensional geometrically exact rod. The special attention is paid to identifying the con- dition that ensures the frame invariance of the resulting discrete approximations. From the perspective of symmetry, this requirement is equivalent to the commutativity of the employed interpolation operator I with the action of the special Euclidean group SE（3）, or I is SE（3）-equivariant. This geometric criterion helps to clarify several subtle issues about the interpolation of finite rotation. It leads us to reexamine the finite element for- mulation first proposed by Simo in his work on energy-momentum conserving algorithms. That formulation is often mistakenly regarded as non-objective. However, we show that the obtained approximation is invariant under the superposed rigid body motions, and as a corollary, the objectivity of the continuum model is preserved. The key of this proof comes from the observation that since the numerical quadrature is used to compute the integrals, by storing the rotation field and its derivative at the Gauss points, the equiv- ariant conditions can be relaxed only at these points. Several numerical examples are presented to confirm the theoretical results and demonstrate the performance of this al- gorithm.

地铁建设中的限额设计研究(基于价值工程)

工程造价是地铁工程建设管理中一大难题,对工程的功能实现、按期完成、合理投资以及成本控制有着深远的影响。本文在总结前人研究理论的基础上,对地铁工程限额设计进行探索,旨在为业主解决相关实际问题时提供一点管理思路。具体工作如下:1) 针对地铁工程建设的特点,提出限额设计的概念和意义,并将其与价值工程相结合,以期实现更合理的投资分配。2) 以上海地铁13号线为例,对其限额设计工作进行具体分析。

基于城市地铁项目的项目信息门户评价研究

本文以上海市地铁13号线为研究背景,建立了基于城市地铁项目的PIP评价体系,并采用基于相对熵的多属性综合评价法对城市地铁项目中的PIP进行评价,最后运用实际案例验证了评价方法的有效性,从而更好地实现了PIP在城市地铁项目中的运用。

On the geometric phase in the spatial equilibria of nonlinear rods

Geometric phases have natural manifestations in large deformations of geometrically exact rods. The primary concerns of this article are the physical implications and observable consequences of geometric phases arising from the deformed patterns exhibited by a rod subjected to end moments. This mechanical problem is classical and has a long tradition dating back to Kirchhoff. However, the perspective from geometric phases seems to go more deeply into relations between local strain states and global geometry of shapes, and infuses genuinely new insights and better understanding, which enable one to describe this kind of deformation in a neat and elegant way. On the other hand, visual representations of these deformations provide beautiful illustrations of geometric phases and render the meaning of the abstract concept of holonomy more direct and transparent.

Nitrogen-tailored quasiparticle energy gaps of polyynes

Polyyne,an sp~1-hybridized linear allotrope of carbon,has a tunable quasiparticle energy gap,which depends on the terminated chemical ending groups as well as the chain length.Previously,nitrogen doping was utilized to tailor the properties of different kinds of allotrope of carbon.However,how the nitrogen doping tailors the properties of the polyyne remains unexplored.Here,we applied the GW method to study the quasiparticle energy gaps of the N-doped polyynes with different lengths.When a C atom is substituted by an N atom in a polyyne,the quasiparticle energy gap varies with the substituted position in the polyyne.The modification is particularly pronounced when the second-nearest-neighboring carbon atom of a hydrogen atom is substituted.In addition,the nitrogen doping makes the Fermi level closer to the lowest unoccupied molecular orbital,resulting in an n-type semiconductor.Our results suggest another route to tailor the electronic properties of polyyne in addition to the length of polyyne and the terminated chemical ending groups.

Nucleation Thermodynamics inside Micro/nanocavity

A thermodynamic approach at the nanometer scale was performed for the heterogeneous nucleation inside nanocavity, and an analytical expression of the critical energy of nucleation was evaluated considering a rough ball nucleus nucleating inside nanocavity. Compared with the case of the nucleation locating on planar or convex substrate, the critical energy of nucleation inside the concave substrate is the smallest. Based on the thermodynamic and kinetic analyses, at low supersaturation, the smaller the curvature radius of cavity and/or the smaller the contact angle, the smaller the critical energy of nucleation, and the larger the nucleation rate. At high supersaturation, the nucleation rate increases with increasing the contact angle and/or increasing the curvature radius of cavity. In this way, at the low supersaturation, the heterogeneous nucleation rate is larger than the homogeneous one, as the nucleation rate is mainly determined by the heterogeneous nucleation. At the high supersaturation, the heterogeneous nucleation rate is smaller than the homogeneous one, as the nucleation rate is mainly determined by the homogeneous nucleation.

Erratum to:Self-enhancing photothermal conversion of 2D Weyl semimetal WTe_(2)with topological surface states for efficient solar vapor generation

The funding numbers of Guangzhou Basic and Applied Basic Research Foundation and Fundamental Research Funds for the Central Universities in the original version of the paper were wrong.They are corrected as“Guangzhou Basic and Applied Basic Research Foundation(No.202201010243)”and“Fundamental Research Funds for the Central Universities(No.21621019)”.And the two funding numbers in the online version of this paper has been corrected.There is a misspelling in Fig.5(e)and the figure of Graphical abstract,“Photon”on the top right corner of the figures should be corrected to“Phonon”.And the two misspellings in the online version of this paper have been corrected.

Laser-Induced Methanol Decomposition for Ultrafast Hydrogen Production

Methanol(CH_(3)OH)is a liquid hydrogen(H_(2))source that effectively releases H_(2) and is convenient for transportation.Traditional thermocatalytic CH_(3)OH reforming reaction is used to produce H_(2),but this process needs to undergo high reaction temperature(e.g.,200°C)along with a catalyst and a large amount of carbon dioxide(CO_(2))emission.Although photocatalysis and photothermal catalysis under mild conditions are proposed to replace the traditional thermal catalysis to produce H_(2) from CH_(3)OH,they still inevitably produce CO_(2) emissions that are detrimental to carbon neutrality.Here,we,for the first time,report an ultrafast and highly selective production of H_(2) without any catalysts and no CO_(2) emission from CH_(3)OH by laser bubbling in liquid(LBL)at room temperature and atmospheric pressure.

Low-dimensional van der Waals materials for linear-polarization-sensitive photodetection: materials, polarizing strategies and applications

Detecting light from a wealth of physical degrees of freedom(e.g.wavelength,intensity,polarization state,phase,etc)enables the acquirement of more comprehensive information.In the past two decades,low-dimensional van der Waals materials(vdWMs)have established themselves as transformative building blocks toward lensless polarization optoelectronics,which is highly beneficial for optoelectronic system miniaturization.This review provides a comprehensive overview on the recent development of low-dimensional vdWM polarized photodetectors.To begin with,the exploitation of pristine 1D/2D vdWMs with immanent in-plane anisotropy and related heterostructures for filterless polarization-sensitive photodetectors is introduced.Then,we have systematically epitomized the various strategies to induce polarization photosensitivity and enhance the degree of anisotropy for low-dimensional vdWM photodetectors,including quantum tailoring,construction of core–shell structures,rolling engineering,ferroelectric regulation,strain engineering,etc,with emphasis on the fundamental physical principles.Following that,the ingenious optoelectronic applications based on the low-dimensional vdWM polarized photodetectors,including multiplexing optical communications and enhanced-contrast imaging,have been presented.In the end,the current challenges along with the future prospects of this burgeoning research field have been underscored.On the whole,the review depicts a fascinating landscape for the next-generation high-integration multifunctional optoelectronic systems.

通过融合物理神经网络重构稀疏或不完整数据流场的实用方法

高分辨率流场重构被普遍认为是实验流体力学领域的一项艰巨任务,因为测量数据在时间和空间上通常是稀疏或不完整的.具体而言,由于实验设备或测量技术的限制,某些关键区域的数据无法测量.本文提出了一种基于融合物理神经网络(PINN)的不完美数据重建流场的实用方法,该网络将已知数据与物理原理相结合.通过圆柱体的尾流作为测试算例.研究了两种不完美数据训练集,一种是不同稀疏度的速度数据,另一种是不同区域缺失的速度数据.为了加速训练收敛,本文采用了余弦退火算法以提高PINN的计算效率.计算结果表明,该方法不仅可以高精度地重建真实的速度场,而且即使在数据稀疏度达到1%或核心流动区域数据被截断的情况下,也可以精确地预测压力场.这项研究提供了令人鼓舞的结论,即PINN可以作为实验流体力学的有潜力的数据同化方法.

Self-enhancing photothermal conversion of 2D Weyl semimetal WTe_(2)with topological surface states for efficient solar vapor generation

To improve the performance of solar energy-driven water generation,two-dimensional(2D)photothermal materials requisite to be optimized by some strategies such as alloying,combination of plasmonic and defect modulation.However,the challenges faced in practical utilization are the complex preparation process and insufficient solar spectrum absorption.Herein,we propose a strategy of self-enhancing photothermal performance induced by topological surface states(TSSs).2D WTe_(2)is fabricated on the mixed cellulose ester(MCE)for photothermal device.Compared to the MCE and pure water,WTe_(2)@MCE has an excellent photothermal evaporation rate of 1.09 kg·m^(−2)·h^(−1)upon 1 sun irradiation,promoting 6.1 and 3.1 times,respectively.It can be attributed to the characteristics of 2D Weyl semimetal WTe_(2)with TSSs bringing about high optical absorption capacity,low thermal diffusivity,specific heat capacity,and high carrier density,which are strongly proved by experiments and calculation.More importantly,the contribution of TSSs to the enhancement of optical absorption for efficient solar water generation is revealed by the comparative experiment between 2D WTe_(2)with TSSs and that without TSSs.Furthermore,photothermal conversion mechanism is explored in-depth understanding that the photoexcited electrons recombinate with the holes through nonradiative mode for releasing thermal energy by phonons emission via multiple pathway.This work promotes the application of Weyl semimetal material with TSSs in solar water evaporation.

底部导流板对高速列车气动减阻的影响

转向架和车下设备区域是高速列车气动阻力的主要来源之一,基于此,本文提出一种安装于转向架舱前后端的小型导流板装置,以改善列车的底部流动、减小列车的气动阻力.采用IDDES方法对是否安装底部导流板的不同列车模型开展非定常数值仿真,并对导流板的减阻效果和作用机理进行分析.结果表明:底部导流板可以将列车底部高速气流导向地面,减小气流对转向架及车下设备的冲击作用,从而产生显著的气动减阻效果.此外,还讨论了底部导流板不同安装位置对减阻效果的影响,最终得到了实现整车减阻约12%的一种最佳安装方式.同时,导流板还能够减小底部流场在展向上的影响范围,减小列车风,这对铁路沿线工人和平台等候乘客的安全具有更高保障.本研究为高速列车气动减阻提供了新思路、新方法。对节能减耗、可持续发展等具有重要意义.

基于被动控制装置的高速列车转向架区域气动优化

高速列车转向架是重要的气动阻力和噪声来源,这两者都会对高速列车气动性能和乘客的舒适性带来不利影响.在本研究中,将被动控制的方法应用于高速列车转向架舱的设计,以改善其气动性能.本研究引入了两种被动控制措施,即加装扰流片和在转向架舱附近设置导流槽.本文采用改进的延迟分离涡模拟(IDDES)和声学有限元法(FEM),对高速列车不同被动控制策略下的气动特性和气动声学特性进行了数值研究,分析并讨论了被动控制装置对减阻、周围气流和气动噪声特性的影响.研究结果表明,被动控制装置对列车周围气流有重要影响.列车前半部分脉动压力幅值高于后半部分.无论是否加装被动控制装置,第一个转向架处的声压振幅都是最大的.对于远场区域,在转向架舱前安装扰流片和放置导流槽可以明显降低气动阻力和噪声.因此,如本研究所示,采用被动控制方法来改善高速列车气动特性和噪声特性是一种可行的选择.

Numerical studies of static aeroelastic effects on grid fin aerodynamic performances

The grid fin is an unconventional control surface used on missiles and rockets. Although aerodynamics of grid fin has been studied by many researchers, few considers the aeroelastic effects.In this paper, the static aeroelastic simulations are performed by the coupled viscous computational fluid dynamics with structural flexibility method in transonic and supersonic regimes. The developed coupling strategy including fluid–structure interpolation and volume mesh motion schemes is based on radial basis functions. Results are presented for a vertical and a horizontal grid fin mounted on a body. Horizontal fin results show that the deformed fin is swept backward and the axial force is increased. The deformations also induce the movement of center of pressure, causing the reduction and reversal in hinge moment for the transonic flow and the supersonic flow,respectively. For the vertical fin, the local effective incidences are increased due to the deformations so that the deformed normal force is greater than the original one. At high angles of attack, both the deformed and original normal forces experience a sudden reduction due to the interference of leeward separated vortices on the fin. Additionally, the increment in axial force is shown to correlate strongly with the increment in the square of normal force.

Carbon nanotube-dependent synthesis of armchair graphene nanoribbons

Sub-nanometer armchair graphene nanoribbons(GNRs)with moderate band gap have great potential towards novel nanodevices.GNRs can be synthesized in the confined tubular space of single-walled carbon nanotubes(SWCNTs),in which precursor molecules have been specifically designed to form the GNRs with certain width and edge.However,it is still unexplored how the diameter and metallicity of SWCNTs influence the synthesis of the GNRs.Herein,we applied a series of SWCNTs with different average diameters to study the diameter-dependent synthesis of GNRs.By using Raman spectroscopy and transmission electron microscopy,we found that the width of the GNRs can be tailored by the diameter of the SWCNTs.Especially,the SWCNTs with average diameter of 1.3 nm produced 6 and 7 armchair GNRs with the highest yield,which can be well explained by considering the width of the GNRs and van der Waals radius of hydrogen and carbon atoms.In addition,semiconducting and metallic SWCNTs produced GNRs with different yields,which could attribute to different diameter distributions and density of defects.These results enable the possibility of a high-yield production of certain armchair graphene nanoribbons in large scale,which would benefit future applications as semiconductor with sub-nanometer in width.

Ultrafast dynamics of photoexcited carriers and coherent phonons in ultrathin Bi;Te;thermoelectric films

The ultrafast dynamics of photoexcited carriers and coherent phonons in ultrathin Bi;Te;thermoelectric films are studied through transient differential transmission spectroscopy.An ultralow frequency coherent optical phonon at 0.16 THz emerges,especially in ultrathin films,and it is ascribed to interlayer breathing modes.It can divide the ultrathin films into two groups which have outof-phase vibration along the normal of a film plane,causing a destructive interference between in-plane propagating thermal waves in the two groups of quintuple layers,and thus possibly reducing the thermal conductivity of the ultrathin films.The excitation power dependence of ultrafast dynamics reveals carrier-carrier scattering dominating thermalization,which provides a microscopic understanding of the reported high electrical conductivity and anomalously high power factor of ultrathin Bi;Te;films at room temperature.