Shanghai VLBI Correlator

This report summarizes the activities of the Shanghai VLBI Correlator during 2012

Exact Solution of boundary-dissipated transverse field Ising model: structure of Liouvillian spectrum and dynamical duality

We study the boundary-dissipated transverse field Ising model described by a Lindblad Master equation and exactly solve its Liouvillian spectrum in the whole parameter space. By mapping the Liouvillian into a Su-Schrieffer-Heeger model with imaginary boundary potentials under a parity constraint, we solve the rapidity spectrum analytically and thus construct the Liouvillian spectrum strictly with a parity constraint condition. Our results demonstrate that the Liouvillian spectrum displays four different structures, which are characterized by different numbers of segments. By analyzing the properties of rapidity spectrum, we can determine the phase boundaries between different spectrum structures analytically and prove the Liouvillian gap fulfilling a duality relation in the weak and strong dissipation region. Furthermore, we unveil the existence of a dynamical duality, i.e., the long-time relaxation dynamics exhibits almost the same dynamical behavior in the weak and strong dissipation region as long as the duality relation holds true.Comment: 6 pages, 4 figure

Cardioprotective effects of Dan-Yang-Fu-Xin decoction on chronic heart failure in rats

Purpose: To evaluate the cardioprotective effects and possible mechanisms of Dan-Yang-Fu-Xin decoction (DYFX) in a rat chronic heart failure (CHF).Methods: A CHF rat model induced by ligation of the left anterior descending coronary artery was used to investigate the cardioprotective effects of DYFX. After intragastric administration for 8 weeks, several functional cardiac indices, including fractional shortening (FS), ejection fraction (EF), heart rate (HR) and cardiac output (CO) were assessed by ultrasound examination. Subsequently, inflammatory markers, viz, interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α), myocardial enzymes, namely, lactate dehydrogenase (LDH) and creatine kinase (CK), were also assessed by enzyme-linked immunosorbent assay (ELISA).Results: Intragastric administration of DYFX (200, 400 and 600 mg/kg) significantly reversed the decrease in body weight and increase in cardiac weight (p < 0.05) induced by CHF. Treatment with DYFX also significantly reversed EF, FS, HR, and CO changes in CHF rats. In addition, DYFX inhibited the two inflammatory cytokines (TNF-α and IL-6) and myocardial enzymes (CK and LDH), suggesting that these effects may include the mechanisms of cardioprotectiion involved in attenuation of CHF.Conclusion: DYFX possesses cardioprotective effects involving CHF. The protective mechanisms may include the suppression of expression of inflammatory mediators and myocardial enzymes.Keywords: Dan-Yang-Fu-Xin decoction, Cardioprotection, Chronic heart failure, Inflammatory mediators, Myocardial enzyme

Using Gray-Markov Model and Time Series Model to Predict Foreign Direct Investment Trend for Supporting China’s Economic Development

Foreign direct investment (FDI) is one of the important factors affecting China’s economic development, the prediction of which is the basis of its development and decision-making. Based on elaborating the significant role in China’s economic growth and the status quo of utilizing foreign investment over the period between 2000 and 2016, this chapter attempts to construct Gray-Markov model (GMM) and time series model (TSM) to forecast the trend of China’s utilization of FDI and then compares the precision of two different prediction models to obtain a better one. Results indicate that although it is qualified, traditional Gray model needs to be optimized; GMM is built to help modify the result, improve Gray-related degrees, and narrow the gap with real value. Comparing the accuracy of GMM with that of TSM, we can conclude that the fitting effect of GMM is better. To increase the credibility of these results, this chapter is based on the data of Beijing and Chongqing from 1990 till 2016, also verifying that the fitting effect of GMM is superior to that of the TSM. Then, we can safely draw a conclusion that the prediction model of GMM is more credible, which has a certain referencing value for the utilization of FDI

Bonvalotidine A acetone solvate from Delphinium bonvalotii Franch

The title compound (systematic name: 5,6β-dihy­droxy-1α,14α,16β-trimeth­oxy-4-methyl-7β,8-methyl­enedi­oxy-20-ethyl­aconitan-6-yl acetate acetone monosolvate), C27H41NO8·C3H6O, was isolated from Delphinium bonvalotii Franch, and is a typical C19-diterpenoid alkaloid. The mol­ecule has a lycoctonine carbon skeleton with four six-membered rings and three five-membered rings. Three six-membered rings adopt the chair conformations while the fourth adopts a boat conformation, while the five-membered rings have the envelope conformations. The solvent mol­ecule links with the organic mol­ecule via a classical O—H⋯O hydrogen bond. Weak C—H⋯O hydrogen bonding is present in the structure. An intra­molecular O—H⋯O hydrogen bond also occurs

The functions and clinical applications of tumor-derived exosomes

Exosomes are extracellular vesicles with diameters ranging from 30 to 150 nm. They can be secreted by all cell types and transfer information in the form of their contents, which include proteins, lipids and nucleic acids, to other cells throughout the body. They have roles in normal physiological processes as well as in disease development. Here, we review recent findings regarding tumor-derived exosomes, including methods for their extraction and preservation. We also describe the actions of exosomes in tumorigenesis. The exosomal antigen-presenting effect during antitumor immune responses and its suppressive function in immune tolerance are discussed. Finally, we describe the potential application of exosomes to cancer therapy and liquid biopsy

An Orderly Untangling Model against Arching Effect in Emergency Evacuation Based on Equilibrium Partition of Crowd

To untangle the arching effect of a crowd as much as possible in emergency evacuations, we employ a theoretical model of equilibrium partition of crowd batch. Based on the shortest time arrangement of evacuation, the crowd is divided into appropriate batches according to the occupied time of evacuation channel in order to determine the occupant number of every evacuation passageway. The number of each batch crowd is calculated under the condition that the time of entering the evacuation passageway is equal to the time of crossing over the evacuation passageway. Subsequently, the shortest processing time (SPT) rule establishes the evacuation order of each batch. Taking a canteen of China Three Gorges University as a background, we obtain the waiting time from the first person to the last one entering the evacuation channel in every batch by simulation. This research utilizes data from simulations to observe an untangling process against the arching effect based on the SPT rule. More specifically, evacuation time only lasts for 180.1 s in order and is 1.6 s longer than that in disorder, but the arching effect disappears. Policy recommendations are offered to improve the evacuation scheme in disaster operations

Exact solution of the Bose Hubbard model with unidirectional hopping

A one-dimensional Bose Hubbard model with unidirectional hopping is shown to be exactly solvable. Applying the algebraic Bethe ansatz method, we prove the integrability of the model and derive the Bethe ansatz equations. The exact eigenvalue spectrum can be obtained by solving these equations. The distribution of Bethe roots reveals the presence of a superfluid-Mott insulator transition at the ground state, and the critical point is determined. By adjusting the boundary parameter, we demonstrate the existence of non-Hermitian skin effect even in the presence of interaction, but it is completely suppressed for the Mott insulator state in the thermodynamical limit. Our result represents a new class of exactly solvable non-Hermitian many-body systems, which have no Hermitian correspondence and can be used as a benchmark for various numerical techniques developed for non-Hermitian many-body systems.Comment: 6+8 pages, 2+6 figure

On the local aspect of valleytronics

Valley magnetic moments play a crucial role in valleytronics in 2D hexagonal materials. Traditionally, based on studies of quantum states in homogeneous bulks, it is widely believed that only materials with broken structural inversion symmetry can exhibit nonvanishing valley magnetic moments. Such constraint excludes from relevant applications those with inversion symmetry, as specifically exemplified by gapless monolayer graphene despite its technological advantage in routine growth and production. This work revisits valley-derived magnetic moments in a broad context covering inhomogeneous structures as well. It generalizes the notion of valley magnetic moment for a state from an integrated total quantity to the local field called "local valley magnetic moment" with space-varying distribution. In suitable inversion-symmetric structures with inhomogeneity, e.g., zigzag nanoribbons of gapless monolayer graphene, it is shown that the local moment of a state can be nonvanishing with sizable magnitude, while the corresponding total moment is subject to the broken symmetry constraint. Moreover, it is demonstrated that such local moment can interact with space-dependent electric and magnetic fields manifesting pronounced field effects and making possible a local valley control with external fields. Overall, a path to "local valleytronics" is illustrated which exploits local valley magnetic moments for device applications, relaxes the broken symmetry constraint on materials, and expands flexibility in the implementation of valleytronics

Bis(1,3-diethyl­benzimidazolium) tetra­bromidomercurate(II)

In the title compound, (C11H15N2)2[HgBr4], the tetra­coordinated HgII center of the complex anion adopts a distorted tetra­hedral geometry [Hg—Br = 2.5755 (8)–2.623 (11) Å and Br—Hg—Br = 103.78 (19)–116.4 (3)°]. One of the Br atoms is disordered over two sites [site-occupancy factors = 0.51 (6) and 0.49 (6)]. The N—C—N angles in the cations are 110.7 (6) and 111.4 (7)°. In the crystal packing, a supra­molecular chain is formed via both weak inter­molecular C—H⋯Br hydrogen bonds and π–π aromatic ring stacking inter­actions [centroid–centroid separation = 3.803 (1) Å]