Ring Airy-Like Beams along Predesigned Parabolic Trajectories

By phase-modulating ring Airy Gaussian beams, ring Airy-like beams propagating along predesigned parabolic trajectories are presented which combine the properties of accelerating beams and abruptly autofocusing beams analytically and numerically for the first time. The enhancement of the quadratic term ratio α shortens the autofocus distance and increases the slope of the beams after autofocusing. Interestingly, the main lobe tends to break into pieces as α increases and the possible reasons have been discussed. Furthermore, the distribution factor β and the radius of the primary r₀ can prominently affect the autofocus distance and the intensity at the focal point but do not change the slope of the beams after the autofocusing. In addition, the self-healing properties are validated to be retainable while RAiG beams via predesigned parabolic trajectories with various α.     

任意高差的多档输电线动刚度理论建模

针对目前多档输电线动力特性研究中存在的不足,将任意一档导线视为子结构并基于现有的索振动理论获得了其动张力;利用相邻两档导线的动张力建立了悬垂绝缘子串绕其悬挂点摆动的动力学方程;综合每一档导线的振动方程以及悬垂绝缘子串的摆动方程建立了两档及三档输电线的动力学方程,求解得到由端部位移激励产生的动刚度;通过对动刚度进行分析得到了多档输电线的固有频率以及模态的理论表达形式;建立了小高差的两档及三档导线的有限元模型,理论分析结果与有限元结果一致,验证了理论公式的正确性。本文提出的动刚度理论对于研究多档输电线的动态响应具有重要的应用价值。     

Dissipative quantum phase transition in a biased Tavis-Cummings model

We study the dissipative quantum phase transition(QPT)in a biased Tavis–Cummings model consisting of an ensemble of two-level systems(TLSs)interacting with a cavity mode,where the TLSs are pumped by a drive field.In our proposal,we use a dissipative TLS ensemble and an active cavity with effective gain.In the weak drive-field limit,the QPT can occur under the combined actions of the loss and gain of the system.Owing to the active cavity,the QPT behavior can be much differentiated even for a finite strength of the drive field on the TLS ensemble.Also,we propose to implement our scheme based on the dissipative nitrogen-vacancy(NV)centers coupled to an active optical cavity made from the gainmedium-doped silica.Furthermore,we show that the QPT can be measured by probing the transmission spectrum of the cavity embedding the ensemble of the NV centers.     

零维到三维结构中三核铜自旋阻挫簇单元的磁构关系和反对称交换

量子自旋液体是最近几年刚被人们证实除铁磁体、反铁磁体之外的第三种磁性类型,因其有望解释高温超导的运行机制、改变计算机硬盘信息存储方式而在物理、材料等领域备受关注。自旋阻挫作为量子自旋液体的最小单元可能是解开量子自旋液体诸多问题的钥匙,所以在磁学、电学研究领域再一次成为人们研究的热点。基于文献报道的三核铜配合物[Cu3(μ3-OH)(μ-OPz)3(NO3)2(H2O)2]·CH3OH(1),我们合成了三维金属有机框架配合物{[Ag(HOPz)Cu3(μ3-OH)(NO3)3(OPz)2Ag(NO3)]·6H2O}n(2)(HOPz=甲基(2-吡嗪基)酮肟),并从自旋阻挫的角度对二者磁性质进行对比和详细分析。磁化率数据表明自旋间有很强的反铁磁相互作用和反对称交换。通过包含各向同性和反对称交换的哈密顿算符对两者磁学数据进行拟合并研究其磁构关系,所获最佳拟合参数为:配合物1:Jav=-426 cm^-1,g⊥=1.83,g∥=2.00;配合物2:Jav=-401 cm^-1,g⊥=1.85,g∥=2.00。     

Synthesis, structure and solution properties of the novel polyampholytes based on cellulose

A novel cellulose-based polyampholyte derivative, carboxylethyl quaternized cellulose (CEQC), was homogeneously synthesized by introducing positively charged quaternary ammonium groups and negatively charged carboxyl groups to the backbone of cellulose. The structure and dilute solution properties of CEQCs were characterized with elemental analysis, FTIR, NMR, viscometer, light scattering and zeta-potential measurement. The nitrogen content and total degree of substituent of acylamino and carboxyl groups increased with an increase of the molar ratio of acrylamide to the anhydroglucose unit of quaternized cellulose (QC). The salt-resistance of CEQC was improved remarkably by introducing opposite charged carboxyl to the QC chains. The intrinsic viscosity of the prepared polyampholytes was found to be very sensitive to the pH of the solutions. CEQC-1, the sample with relative low content of carboxyl groups, behaved as a classical cationic polyelectrolyte. However, CEQC-2 and CEQC-3, the samples with higher content of carboxyl groups, displayed typical polyampholyte behavior, and the isoelectric points (IEP) were determined to be 5.0 and 3.8 respectively. This work provided a facile method for the synthesis of novel cellulose-based polyampholytes with different IEP.     

A simple and efficient algorithm for fused lasso signal approximator with convex loss function

We consider the augmented Lagrangian method (ALM) as a solver for the fused lasso signal approximator (FLSA) problem. The ALM is a dual method in which squares of the constraint functions are added as penalties to the Lagrangian. In order to apply this method to FLSA, two types of auxiliary variables are introduced to transform the original unconstrained minimization problem into a linearly constrained minimization problem. Each updating in this iterative algorithm consists of just a simple one-dimensional convex programming problem, with closed form solution in many cases. While the existing literature mostly focused on the quadratic loss function, our algorithm can be easily implemented for general convex loss. We also provide some convergence analysis of the algorithm. Finally, the method is illustrated with some simulation datasets.     

Novel Dual‐Site‐Binding Neuraminidase Inhibitor from Virtual Screening by Pharmacophore and Molecular Dynamics Methods

Neuraminidase is a significant anti‐influenza target that plays crucial role in virus replication cycle. The discovery of 150‐cavity in Group‐1 neuraminidase provides us a novel mentality of designing inhibitor which can bind with both conserved site and 150‐cavity. In order to discover novel dual‐site‐binding inhibitors, a 3D chemical‐feature‐based pharmacophore model was established to cover dual‐site in neuraminidase. The dual‐site‐binding model was consistent in predicting the binding conformation of Group‐1 neuraminidase inhibitor and applied for virtual screening of Specs database. Compound 4 (ZINC05790048) that aligned well to the model was selected after multiple filtrations for molecular dynamics simulations, indicating improved binding energy with neuraminidase. It can sever as the lead compound for a novel series of inhibitors.     

Chicken Egg Yolk Antibody (IgY) Controls Solobacterium moorei Under In Vitro and In Vivo Conditions

Solobacterium moorei is a causative agent in diseases such as oral halitosis, bacteremia, and necrobacillosis-associated thrombophlebitis. The objective of this study was to determine the effectiveness of chicken egg yolk antibody (IgY) in controlling S. moorei. Intact S. moorei cells were used as an immunogen to immunize four White Leghorn laying hens. IgY, extracted from egg yolks obtained from these immunized hens, was purified using water dilution, two-step salt precipitation, and ultrafiltration. The purity of the IgY obtained was approximately 87.3?%. The antibody titer of the IgY was determined by enzyme-linked immunosorbent assay. The antibody titer peaked at 10,000 following the third immunization. In order to evaluate the inhibitory effects of the specific IgY, the growth of S. moorei in liquid media was measured every 12?h using a microplate reader at 600?nm. Biofilm formation of S. moorei was quantified by staining with crystal violet. The specific binding ability of IgY was further confirmed by the use of immunofluorescence and immunoelectron microscopy. Growth and biofilm formation of S. moorei were significantly (P?<?0.05) inhibited by 20 and 40?mg/ml specific IgY compared with the control. The specific IgY also decreased the bacterial level in the oral cavity of mice after infection with S. moorei. This study demonstrates that the growth and biofilm formation of S. moorei can be effectively inhibited by specific IgY. As a result, IgY technology may have application in the control of diseases caused by S. moorei.