Design and Construction of Grape Theme Sightseeing Garden

Taking the grape theme sightseeing garden of Hebei Academy of Forestry Sciences for example,this article discusses the suitable edible and wine making cultivation varieties,vineyard frame and cultivation techniques in the grape theme sightseeing garden,from the perspective of planning and design. The garden landscape design and construction is integrated with sightseeing and garden visiting to highlight the theme of grape sightseeing garden,aimed at achieving purposes of sightseeing,picking,appreciating the beautiful scenery,and enjoying palatable food.

光谱特征关联性分析用于研究CVD生长的单层二硫化钨非均匀性机制

化学气相沉积(CVD)已被证明是生产二维材料(包括二硫化钨(WS_(2)))最有效的方法.然而,CVD生长的WS_(2)单层中存在的应变、掺杂和缺陷的不均匀性会显著影响材料的光学和电子特性,从而影响其器件应用.在本研究中,我们通过CVD方法在蓝宝石衬底上生长了介观尺寸的三角形单层WS_(2),并利用空间分辨的显微拉曼和光致发光(PL)光谱技术系统地表征了单层WS_(2)中的应变、掺杂和非辐射缺陷中心的不均匀性.我们从全域(整个单层WS_(2)三角形)和分区域(如顶点、边缘、中心)两个维度对其拉曼和PL光谱的相关参数(即峰值位置、强度和半峰宽)随位置的变化进行了相关性分析,发现单层WS_(2)三角形的不同区域往往表现出明显不同的应变、掺杂和缺陷状态.这项研究揭示并解释了单层WS_(2)应变、掺杂和缺陷的不均匀性.此外,我们发现当介观尺寸的三角形结构扩展到连续薄膜时,不均匀性大大降低.我们的工作表明,对光谱特征的相关性分析并辅以对物理机制的了解有助于全面理解材料生长带来的不均匀性,并为优化二维材料的生长过程和器件加工提供指导.

Path guided motion synthesis for Drosophila larvae

The deformability and high degree of freedom of mollusks bring challenges in mathematical modeling and synthesis of motions.Traditional analytical and statistical models are limited by either rigid skeleton assumptions or model capacity,and have difficulty in generating realistic and multi-pattern mollusk motions.In this work,we present a large-scale dynamic pose dataset of Drosophila larvae and propose a motion synthesis model named Path2Pose to generate a pose sequence given the initial poses and the subsequent guiding path.The Path2Pose model is further used to synthesize long pose sequences of various motion patterns through a recursive generation method.Evaluation analysis results demonstrate that our novel model synthesizes highly realistic mollusk motions and achieves state-of-the-art performance.Our work proves high performance of deep neural networks for mollusk motion synthesis and the feasibility of long pose sequence synthesis based on the customized body shape and guiding path.

Analogous comparison unravels heightened antiviral defense and boosted viral infection upon immunosuppression in bat organoids

Horseshoe bats host numerous SARS-related coronaviruses without overt disease signs.Bat intestinal organoids,a unique model of bat intestinal epithelium,allow direct comparison with human intestinal organoids.We sought to unravel the cellular mechanism(s)underlying bat tolerance of coronaviruses by comparing the innate immunity in bat and human organoids.We optimized the culture medium,which enabled a consecutive passage of bat intestinal organoids for over one year.Basal expression levels of IFNs and IFN-stimulated genes were higher in bat organoids than in their human counterparts.Notably,bat organoids mounted a more rapid,robust and prolonged antiviral defense than human organoids upon Poly(I:C)stimulation.TLR3 and RLR might be the conserved pathways mediating antiviral response in bat and human intestinal organoids.The susceptibility of bat organoids to a bat coronavirus CoV-HKU4,but resistance to EV-71,an enterovirus of exclusive human origin,indicated that bat organoids adequately recapitulated the authentic susceptibility of bats to certain viruses.Importantly,TLR3/RLR inhibition in bat organoids significantly boosted viral growth in the early phase after SARS-CoV-2 or CoV-HKU4 infection.Collectively,the higher basal expression of antiviral genes,especially more rapid and robust induction of innate immune response,empowered bat cells to curtail virus propagation in the early phase of infection.

Effects of substrate type and material-substrate bonding on high-temperature behavior of monolayer WS2

This study reveals that the interaction between a 2D material and its substrate can significantly modify its electronic and optical properties, and thus can be used as a means to optimize these properties. High-temperature （25-500℃） optical spectroscopy, which combines Raman and photoluminescence spectroscopies, is highly effective for investigating the interaction and material properties that are not accessible at the commonly used cryogenic temperature （e.g., a thermal activation process with an activation of a major fraction of the bandgap）. This study investigates a set of monolayer WS2 films, either directly grown on sapphire and SiO2 substrates by CVD or transferred onto SiO2 substrate. The coupling with the substrate is shown to depend on the substrate type, the material- substrate bonding （even for the same substrate）, and the excitation wavelength. The inherent difference in the states of strain between the as-grown and the transferred films has a significant impact on the material properties.

Mathematical foundation of Liutex theory

Liutex is a mathematical definition of vortex,which is called the third generation of vortex definition and identification.This paper introduces the mathematical foundation of the Liutex theoretical system including differences in definition and operations between tensor/vector and matrix.The right version of velocity gradient tensor matrix is given to correct the old version which has been widely distributed by many mathematics and fluid dynamics textbooks.A unique velocity gradient principal matrix is provided.The mathematical foundation for Liutex definition is given.The coordinate rotation(Q-and P-rotation)for principal coordinate system and principal matrix is derived,which is the key issue of the new fluid kinematics.The divergence of velocity gradient tensor is given in different forms which may be beneficial in developing new governing equations for fluid dynamics.

Principal coordinates and principal velocity gradient tensor decomposition

Helmholtz velocity decomposition and Cauchy-Stokes tensor decomposition have been widely accepted as the foundation of fluid kinematics for a long time.However,there are some problems with these decompositions which cannot be ignored.Firstly,Cauchy-Stokes decomposition itself is not Galilean invariant which means under different coordinates,the stretching(compression)and deformation are quite different.Another problem is that the anti-symmetric part of the velocity gradient tensor is not the proper quantity to represent fluid rotation.To show these two drawbacks,two counterexamples are given in this paper.Then“principal coordinate”and“principal decomposition”are introduced to solve the problems of Helmholtz decomposition.An easy way is given to find the Principal decomposition which has the property of Galilean invariance.

Correlation analysis among vorticity,Q method and Liutex

Influenced by the fact that vorticity represents rotation for rigid body,people believe this idea also works for fluid flow.However,the vortex predictions by vorticity do not match experimental results,which drove scientists to look for more appropriate methods to identify vortex.All vortex identification methods can be categorized into three generations.The vorticity-based method is classified as the first generation.Methods relying on eigenvalues of velocity gradient tensor are considered as the second generation.People still believe vorticity is vortex since vorticity theory looks correct in mathematics,but all other methods are only scalars and unable to indicate the swirl direction.Recently,a new vortex identification method called Liutex is innovated.It is regarded as the third-generation method,not only overcoming all previous methods’drawbacks but also having a clear physical meaning.The direction of Liutex represents the swirl axis of rotation,and its strength is equal to twice the angular speed.In this paper,we did a correlation analysis between vorticity,Q,λ_(ci),λ_(2)methods and Liutex based on a direct numerical simulation(DNS)case of boundary layer transition.The results show that the correlation between vorticity and Liutex is very small or even negative in strong shear regions,which demonstrates that using vorticity to detect vortex lacks scientific foundation and vorticity is not appropriate to represent vortex.The correlation analysis also shows that the second generation is contaminated too by shear and thus is not accurate to identify the vortex structure.

Liutex based new fluid kinematics

The traditional Cauchy-Stokes(C-S)decomposition states that the velocity gradient tensor can be decomposed into a symmetric tensor and an anti-symmetric tensor,namely the strain-rate tensor and the vorticity tensor.However,there are two problems with the C-S decomposition.One is that the anti-symmetric(vorticity)tensor cannot represent the fluid rotation or vortex.Another is that the symmetric(strain-rate)tensor cannot distinguish the stretching/compression and shear.Since vorticity cannot distinguish between the non-rotational shear and the rigid rotation,vorticity has been decomposed into a rigid rotation part called“Liutex”and an anti-symmetric shear in our previous work.A Liutex-based principal coordinate system has been proposed,and the corresponding velocity gradient tensor decomposition,called the principal decomposition,is presented in this principal coordinate system,which results in:(1)a Liutex tensor that represents rigid rotation,(2)a tensor that represents pure shear and(3)a tensor that represents stretching/compression.However,each point has its own principal coordinate system,which implies that the principal decomposition is performed in different principal coordinate systems,not the original(global)coordinate system.To address this issue,the principal decomposition in the original coordinate system is derived in this paper,and,therefore,provides a new kinematic approach to study the local rigid rotation,pure shear,and stretching/compression.The principal decomposition is unique,Galilean invariant and has clear physical meaning.The new velocity gradient tensor decomposition could become a foundation for new fluid kinematics.

Stretching and shearing contamination analysis for Liutex and other vortex identification methods

The newly developed vortex-identification method,Liutex,has provided a new systematic description of the local fluid rotation,which includes scalar,vector,and tensor forms.However,the advantages of Liutex over the other widely used vortexidentification methods such as Q,Δ,λ2,andλci have not been realized.These traditional methods count on shearing and stretching as a part of vortex strength.But,in the real flow,shearing and stretching do not contribute to fluid rotation.In this paper,the decomposition of the velocity gradient tensor is conducted in the Principal Coordinate for uniqueness.Then the contamination effects of stretching and shearing of the traditional methods are investigated and compared with the Liutex method in terms of mathematical analysis and numerical calculations.The results show that the Liutex method is the only method that is not affected by either stretching or shear,as it represents only the local fluid rigid rotation.These results provide supporting evidence that Liutex is the superior method over others.

A letter for objective Liutex

Vortex structures,detected by the existing popular vortex identification methods,of the same case are generally different if the results are measured by different observers,who are moving with different coordinate systems.These coordinate systems can be inertial or non-inertial.Galilean invariance can solve the moving observer problems in different inertial coordinate systems.A variable is invariant under Galilean transformation is called Galilean invariant.Galilean invariant vortex identification methods can provide invariant vortex structures based on different inertial observers.However,for some situations,the observers are non-inertial,e.g.,the observer is sitting on an aircraft which is accelerating or rotating.In such a situation,it requires to use an objective method.Objectivity represents a property that one variable is not observer-dependent(the observer’s motion can be either inertial or non-inertial).A strategy based on a zero-vorticity(measured in inertial frame)reference point is proposed in this letter to find the objective vortex structure.Liutex is chosen as the vortex indicator and two numerical examples are used to test the proposed strategy.The results show that the strategy is effective.

Correction to: Stretching and shearing contamination analysis for Liutex and other vortex identification methods

Correction to:Adv Aerodyn 3,8(2021)https://doi.org/10.1186/s42774-020-00060-9 After publication of this article[1],it is noticed letter‘a’is missing from the below sentence in section 6.2‘Adding stretching components’:The subscript“”means“adding”the stretching components.The correct sentence should be。