Robust measurement of orbital angular momentum of a partially coherent vortex beam under amplitude and phase perturbations

The ability to overcome the negative effects,induced by obstacles and turbulent atmosphere,is a core challenge of long-distance information transmission,and it is of great significance in free-space optical communication.The spatial-coherence structure,that characterizes partially coherent fields,provides a new degree of freedom for carrying information.However,due to the influence of the complex transmission environment,the spatial-coherence structure is severely damaged during the propagation path,which undoubtedly limits its ability to transmit information.Here,we realize the robust far-field orbital angular momentum(OAM)transmission and detection by modulating the spatial-coherence structure of a partially coherent vortex beam with the help of the cross-phase.The cross-phase enables the OAM information,quantified by the topological charge,hidden in the spatial-coherence structure can be stably transmitted to the far field and can resist the influence of obstructions and turbulence within the communication link.This is due to the self-reconstruction property of the spatial-coherence structure embedded with the cross-phase.We demonstrate experimentally that the topological charge information can be recognized well by measuring the spatial-coherence structure in the far field,exhibiting a set of distinct and separated dark rings even under amplitude and phase perturbations.Our findings open a door for robust optical signal transmission through the complex environment and may find application in optical communication through a turbulent atmosphere.

根据浅层剪切波速度剖面(深度<30m)估计V_S(30)的新方法

建筑规范中,地表到地下30m深度的走时平均剪切波速度[VS(30)]是场地分类的重要参数。利用在两个不同深度[VS(z1)和VS(z2),且z1<z2<30m]下得到的走时平均剪切波速度,提出了用井孔中测量的浅层剪切波速度剖面估计VS(30)的新方法。选用剪切波速度剖面达30m的日本KiK-net台网594个井孔和美国加利福尼亚州的135个井孔的数据,通过VS(30)实测值与VS(30)估计值之间的相关性和用VS(30)估算值给出场地分类的准确性验证了该新方法的可靠性。结果显示,该方法可以提高VS(30)的准确度,且VS(30)的实测值与估算值之间的皮尔逊相关系数等于0.999,VS(30)的估算值给出的场地分类准确率大于96%,而z1≥10m,z2=25m。利用来自日本的数据研究了VS(z)的实测值与估算值在6个不同深度(50,100,150,200,400,600m)时的相关性,结果表明当所选的两个深度(z1,z2)接近某个深度z时,利用该假设方法估算的VS(z)(z≥50m)的准确度有所提高。相比Boore(2004)和Boore等(2011)的方法,新方法不需要对大量场地做回归分析以获得经验关系,没有区域性依赖,准确度有显著提高,且在世界的许多地方均有潜在的用途。

Three Indication Variables and Their Performance for the Troubled-Cell Indicator using K-Means Clustering

In Zhu,Wang and Gao(SIAM J.Sci.Comput.,43(2021),pp.A3009–A3031),we proposed a new framework of troubled-cell indicator(TCI)using K-means clustering and the numerical results demonstrate that it can detect the troubled cells accurately using the KXRCF indication variable.The main advantage of this TCI framework is its great potential of extensibility.In this follow-up work,we introduce three more indication variables,i.e.,the TVB,Fu-Shu and cell-boundary jump indication variables,and show their good performance by numerical tests to demonstrate that the TCI framework offers great flexibility in the choice of indication variables.We also compare the three indication variables with the KXRCF one,and the numerical results favor the KXRCF and the cell-boundary jump indication variables.

Hunt for the tipping point during endocrine resistance process in breast cancer by dynamic network biomarkers

Acquired drug resistance is the major reason why patients fail to respond to cancer therapies.It is a challenging task to deter.mine the tipping point of endocrine resistance and detect the associated molecules.Derived from new systems biology theory, the dynamic network biomarker (DNB) method is designed to quantitatively identify the tipping point of a drastic system transition and can theoretically identify DNB genes that play key roles in acquiring drug resistance.We analyzed time-course mRNA sequence data generated from the tamoxifen-treated estrogen receptor (ER)-positive MCF-7 cell line, and identified the tipping point of endocrine resistance with its leading molecules.The results show that there is interplay between gene mutations and DNB genes, in which the accumulated mutations eventually affect the DNB genes that subsequently cause the change of transcriptional landscape, enabling full-blown drug resistance. Survival analyses based on clinical datasets validated that the DNB genes were associated with the poor survival of breast cancer patients.The results provided the detection for the pre-resistance state or early signs of endocrine resistance.Our predictive method may greatly benefit the scheduling of treatments for complex diseases in which patients are exposed to considerably different drugs and may become drug resistant.

Performance evaluation for sustainability of wind energy project using improved multi-criteria decision-making method

Wind power can be an efficient way to alleviate energy shortage and environmental pollution,and to realize sustainable development in terms of energy generation.The sustainability assessment of a wind project among its alternatives is a complex task that cannot be solely simplified to environmental or economic feasibility.It requires the consideration of its technological and social aspects as well as other circumstances.This paper proposes a new method for selecting the most sustainable wind projects.The method is based on multi-criteria decision-making techniques.The analytic hierarchy process and entropy weight method are combined to determine the weights of evaluation indexes,and an innovative index-weight optimization method based on the Lagrange conditional extremum algorithm.The fuzzy technique for order preference by similarity to the ideal solution is applied to rank wind project alternatives considering functionality and proportionality of the system.Moreover,the sensitive analysis is applied to verify the robustness of the proposed method.The applicability of the method is demonstrated on a case study from China,where three main wind projects are analytically compared and ranked.The results indicated that the sustainable level of calculated wind power can provide a reference point for the planning and operation of the wind project.The results show that the proposed method is of both theoretical significance and practical application in engineering.

Adsorption behavior of ammonium by a bioadsorbent-Boston ivy leaf powder

The adsorption behaviors of ammonium ions from aqueous solution by a novel bioadsorbent, the Boston ivy （Parthenocissus tricuspidata） leaf powder （BPTL） were investigated. The SEM images and FT-IR spectra were used to characterize BPTL. The mathematical models were used to analyze the adsorption kinetics and isotherms. The optimum pH range for ammonium adsorption by BPTL was found to be 5-10. The adsorption reached equilibrium at 14 b.r, and the kinetic data were well fitted by the Logistic model. The intraparticle diffusion was the main rate-controlling step of the adsorption process. The high temperature was favorable to the ammonium adsorption by BPTL, indicating that the adsorption was endothermic. The adsorption equilibrium fitted well to both the Langmuir model and Freundlich model, and the maximum monolayer adsorption capacities calculated from Langmuir model were 3.37, 5.28 and 6.59 mg N/g at 15, 25 and 35~C, respectively, which were comparable to those by reported minerals. Both the separation factor （RL） from the Langmuir model and Freundiich exponent （n） suggested that the ammonium adsorption by BPTL was favorable. Therefore, the Boston ivy leaf powder could be considered a novel bioadsorbent for ammonium removal from aqueous solution.

Voltage Security Operation Region Calculation Based on Improved Particle Swarm Optimization and Recursive Least Square Hybrid Algorithm

Large-scale voltage collapse incidences, which result in power outages over large regions and extensive economic losses, are presently common occurrences worldwide. To avoid voltage collapse and operate more safely and reliably, it is necessary to analyze the voltage security operation region(VSOR) of power systems, which has become a topic of increasing interest lately. In this paper, a novel improved particle swarm optimization and recursive least square(IPSO-RLS) hybrid algorithm is proposed to determine the VSOR of a power system. Also, stability analysis on the proposed algorithm is carried out by analyzing the errors and convergence accuracy of the obtained results. Firstly, the voltage stability and VSOR-surface of a power system are analyzed in this paper. Secondly, the two algorithms,namely IPSO and RLS algorithms, are studied individually.Based on this understanding, a novel IPSO-RLS hybrid algorithm is proposed to optimize the active and reactive power,and the voltage allowed to identify the VSOR-surface accurately. Finally, the proposed algorithm is validated by using a simulation case study on three wind farm regions of actual Hami Power Grid of China in DIg SILENT/Power Factory software.The error and accuracy of the obtained simulation results are analyzed and compared with those of the particle swarm optimization(PSO), IPSO and IPSO-RLS hybrid algorithms.

Forming electron traps deactivates self-assembled crystalline organic nanosheets toward photocatalytic overall water splitting

Most biological photoredox reactions occur in sophisticated molecular assemblies consisting of highly organized light-harvesting moieties and catalytic centers.Mimicking these prototypes by creating supramolecular assemblies could be a potentially viable approach toward artificial photosynthesis.Although self-assembled organic materials are known to carry out water splitting reactions,developing self-assembled organic materials for photocatalytic overall water splitting still remains a critical challenge.Herein,we first demonstrate that crystalline organic nanosheets assembled from linear oligo(phenylene butadiynylene)(OPB)are able to catalyze overall water splitting under visible light irradiation.Further investigations reveal that the photocatalytic activity of self-assembled organic structures is closely related to the crystalline structure along with the corresponding electronic structure.Structural disorders in OPB nanosheets and extrinsic factors such as adsorbed water molecules will induce the formation of electron traps which can make the OPB nanosheets thermodynamically unfavorable for photocatalytic overall water splitting.The deactivation mechanism unveiled in this study provides crucial insights into the assembling of artificial organic materials for future solar-to-chemical energy conversion.

Overexpression of GhPFN2 enhances protection against Verticillium dahliae invasion in cotton

Growing evidence indicates that actin cytoskeleton is involved in plant innate immune responses, but the functional mechanism remains largely unknown. Here, we investigated the behavior of a cotton profilin gene （GhPFN2） in response to Verticillium dahliae invasion, and evaluated its contribution to plant defense against this soil-borne fungal pathogen. GhPFN2 expression was up-regulated when cotton root was inoculated with V. dahliae, and the actin architecture was reorganized in the infected root cells, with a clear increase in the density of filamentous actin and the extent of actin btmdling. Compared to the wild type, GhPFN2-overexpressing cotton plants showed enhanced protection against V. dahliae infection and the actin cytoskeleton organization in root epidermal cells was clearly altered, which phenocopied that of the wild-type （WT） root cells challenged with V. dahliae. These results provide a solid line of evidence important for defense against V. dahliae infection. showing that actin cytoskeleton reorganization involving GhPFN2 is

Fully Conjugated Ladder Polymers as Metal-Free Photocatalysts for Visible-Light-Driven Water Oxidation

Green plants and algae utilize complicated yet delicate structures to oxidize water into molecular oxygen while releasing electrons for dark reactions.The photocatalytic water oxidation reaction in photosystem Ⅱ is challenging as it Involves in transferring multiple electrons and protons and requires a large overpotential.Herein,for the first time,we report that conjugated ladder polymers with suitable band structures are potential metal-free photocatalysts for efficient and stable water oxidation.Two structurally similar conjugat-ed ladder polymers are synthesized via the condensation reaction between amine-and ketone-containing monomers.Photocatalytic tests reveal that different polymer structures exhibit different photocatalytic performances which are determined by their inherent optoelectronics properties.Meanwhile,our first-principles calculations confirm that photocatalytic water oxidation is thermodynamically feasible for both conjugated ladder polymers under visible light irradiation.Our study unveils a novel class of polymer materials for the water oxidation reaction and further indicates that metal-free photocatalysts hold great potential for future solar-to-chemical conversion.

The two domains of cotton WLIM1a protein are functionally divergent

Our previous study demonstrated that WLIMla has dual roles in fiber elongation and secondary cell wall synthesis in upland cotton, and the protein acts either as an actin-binding protein or as a transcription factor. Because WLIMla consists of two different LIM domains, it is possible that these elements contribute differentially to the dual functions of the protein. In this study, we dissected the two LIM domains and characterized their biochemical functions. By using red fluorescent protein （RFP） fusion, co-sedimentation, and DNA binding methods, we found that the two domains of WLIM 1 a, domain 1 （D 1） and domain2 （D2）, possessed different biochemical properties. While D1 contributed primarily to the actin filament-bundling activity of WLIMla, D2 contributed to the DNA-binding activity of the protein; both D1 and D2 relied on a linker sequence for their ac- tivities. In addition, we found that WLIMla and its two LIM domains form dimers in vitro. These results may lead to a better understanding of the molecular mechanisms of dual functions of WLIMla during cotton fiber development.