Local Flow Regime Transition Criteria of Gas-Liquid Two-phase Flow in Vertical Upward Tube with a Horizontal Rod

The upward multiphase cross flow and heat transfer in the vertical tube may occur in oil production and chemical facilities. In this study, the local flow patterns of an upward gas-water two phase cross flow in a vertical tube with a horizontal rod have been investigated with an optical probe and the digital high speed video system. The local flow patterns are defined as the bubble, slug, churn and annular flow patterns. Optical probe signals are ana- lyzed in terms of probability density function, and it is proved that the local flow patterns can be recognized by this method. The transition mechanisms between the different flow patterns have been analyzed and the corresponding transitional models are proposed. Finally, local flow pattern maps of the upward gas-water two-phase flow in the vertical tube with a horizontal rod are constructed.

LOCAL EQUILIBRIUM METHOD IN STUDYING PHASE DIAGRAM OF Mn-MnO SYSTEM

A special method based on the local equilibrium principle has been introduced in the research of the phase diagram of Mn-MnO system.With this method,the problems of volatilization of Mn and the corrosion of Mn and MnO to refractory materials were prevented efficiently.The solubility of oxygen in Mn and the composition of the interface between MnO and Mn were determined.Partial phase diagram of Mn-MnO system were constructed according to pres- ent experimental results.

Postoperative chemotherapy with S-1 plus oxaliplatin versus S-1alone in locally advanced gastric cancer(RESCUE-GC study): a protocol for a phase Ⅲ randomized controlled trial

Background： The ACTS-GC study had shown postoperative adiuvant therapy with S-1 improved survival of patients with locally advanced gastric cancer. Addition of oxaliplatin to S-1 is considered to be acceptable as one of the treatment options for gastric cancer patients after radical gastrectomy with D2 lymph node excision. Methods： We have commenced a randomized phase III trial in December 2016 to evaluate S-I plus oxaliplatin compared with S-1 alone in the adjuvant setting for locally advanced gastric cancer. A total of 564 patients will be accrued from 13 Chinese institutions in two years. The primary endpoint is 3-year relapse-free survival. The secondary endpoints are 5-year overall survival, proportion of patients who complete the postoperative chemotherapy and incidence of adverse events. Ethic and dissemination： The trial has been approved by the institutional review board of each participating institution and it was activated on December, 2016. The enrollment will be finished in December, 2018. Patient＇s follow-up will be ended until December, 2023. Trial registration： ClinicalTrials.gov, identifier： NCT02867839. Registered on August 4, 2016.

Anderson Localization Light Guiding in a Two-Phase Glass

Anderson localization has been realized in several different systems over the years. In this paper we describe a rather unique manifestation of the phenomenon occurring in a two-phase glass composition that guides light. The glasses are a borate or alkali borosilicate composition that when heated separates into two distinct phases of different compositions, a high index phase and a low index phase. When the glass is heated with a specific thermal schedule to develop the phase separation it is then drawn into a rod or fiber, the particulate phase forms elongated strands resulting in a random cross-sectional refractive index pattern. This pattern of refractive index is maintained along the length producing a light guiding behavior over a significant distance that we propose is a manifestation of an Anderson localization phenomenon.

NON-LOCAL MODELING ON MACROSCOPIC DOMAIN PATTERNS IN PHASE TRANSFORMATION OF NiTi TUBES

Recent experiments revealed many new phenomena of the macroscopic domain patterns in the stress-induced phase transformation of a superelastic polycrystalline NiTi tube during tensile loading. The new phenomena include deformation instability with the formation of a helical domain, domain topology transition from helix to cylinder, domain-front branching and loading-path dependence of domain patterns. In this paper, we model the polycrystal as an elastic continuum with nonconvex strain energy and adopt the non-local strain gradient energy to account for the energy of the diffusive domain front. We simulate the equilibrium domain patterns and their evolution in the tubes under tensile loading by a non-local Finite Element Method （FEM）. It is revealed that the observed loading-path dependence and topology transition of do- main patterns are due to the thermodynamic metastability of the tube system. The computation also shows that the tube-wall thickness has a significant effect on the domain patterns： with fixed material properties and interfacial energy density, a large tube-wall thickness leads to a long and slim helical domain and a severe branching of the cylindrical-domain front.

Simulation of bacterial flagellar phase transition by non-convex and non-local continuum modeling

Bacterial flagellar filament can undergo a stress-induced polymorphic phase transition in both vitro and vivo environments.The filament has 12 different helical forms(phases) characterized by different pitch lengths and helix radii.When subjected to the frictional force of flowing fluid,the filament changes between a left-handed normal phase and a right-handed semi-coiled phase via phase nucleation and growth.This paper develops non-local finite element method(FEM) to simulate the phase transition under a displacement-controlled loading condition(controlled helix-twist).The FEM formulation is based on the Ginzburg-Landau theory using a one-dimensional non-convex and non-local continuum model.To describe the processes of the phase nucleation and growth,viscosity-type kinetics is also used.The non-local FEM simulation captures the main features of the phase transition:two-phase coexistence with an interface of finite thickness,phase nucleation and phase growth with interface propagation.The non-local FEM model provides a tool to study the effects of the interfacial energy/thickness and loading conditions on the phase transition.

非厄米准周期系统中的二次局域体态和局域-扩展的边缘态

局域化是物理学中一个基础且极具潜力的研究领域.基于广义Su-Schrieffer-Heeger模型,本文针对其非厄米项以准周期、非对角形式出现的特点,提出了一种新的分析框架,旨在分别探讨体态与边缘态的局域化特性.对于体态,它可以经历由准无序诱导的扩展-共存-局域-共存-局域的转变,或者是由非厄米特性引起的共存-局域-共存-局域的转变.同时边缘态可以被破坏和恢复,且其拓扑相变与局域化转变完全同步.最后,发现在局域化转变点处归一化参与率的导数展现出明显的不连续性.本文的结果不仅展示了体态和边缘态局域化性质的多样性,而且为局域化研究开辟了一个新的研究视角.

Laser-induced phase conversion of n-type SnSe_(2)to p-type SnSe

We report a facile phase conversion method that can locally convert n-type SnSe_(2)into p-type SnSe by direct laser irradiation.Raman spectra of SnSe_(2)flakes before and after laser irradiation confirm the phase conversion of SnSe_(2)to SnSe.By performing the laser irradiation on SnSe_(2)flakes at different temperatures,it is found that laser heating effect induces the removal of Se atoms from SnSe_(2)and results in the phase conversion of SnSe_(2)to SnSe.Lattice-revolved transmission electron microscope images of SnSe_(2)flakes before and after laser irradiation further confirm such conversion.By selective laser irradiation on SnSe_(2)flakes,a pattern with SnSe_(2)/SnSe heteostructures is created.This indicates that the laser induced phase conversion technique has relatively high spatial resolution and enables the creation of micron-sized in-plane p-n junction at predefined region.

剪切流动亚临界转捩中的时空间歇性和相变研究进展

剪切流动中层流向湍流的转捩是流体力学中的一个经典难题.近些年在亚临界转捩方面取得了若干重要进展,特别是在转捩的时空特征方面.研究发现,亚临界转捩中湍流以局地湍流形式存在,且表现出复杂的时空间歇性.对局地湍流结构及其时空复杂性的研究逐步揭示了转捩现象和统计物理中的连续型相变之间的关系:流动转捩可能属于一个可描述广泛临界现象的相变普适类,即导向逾渗相变普适类.目前学界仍在试图证明这种相变比拟适用于所有壁面剪切流动中的亚临界转捩.近期在泰勒-库埃特流动实验中给出了相变的直接证据,但对于管道和槽道流动,由于转捩临界点附近系统演化的巨大时间和空间尺度,实验和计算都难以足够靠近临界点进行直接验证,而且槽道流转捩临界点附近湍流的时空特征与导向逾渗相变之间的关系仍不明晰.因而,该比拟的普适性还有待进一步的确认.

Microstructural Evolution of Localized Shear Bands Induced during Explosion in Ti-6Al-4V Alloy

Microstructures of the localized shear bands generated during explosion with a thick-walled cylinder specimen in Ti-6AI-4V alloy, were characterized by TEM and SEM. The results show that the twinning is a major mode of deformation, and the distortion-free grains in the bands with the size of 10μm in diameter were proposed to be the re-crystallization during dynamic explosion. The further observations show that the α→α2 phase transformation may occur in the bands, and this kind of transformation could be confirmed by its dark field image and electron diffraction analysis. Analysis shows that there is specified orientation between the α and α2 Phases.

Phase transition and thermodynamic properties of TiO_2 from first-principles calculations

The pressure induced phase transitions of TiO2 from anatase to columbite structure and from rutile to columbite structure and the temperature induced phase transition from anatase to rutile structure and from columbite to rutile structure are investigated by ab initio plane-wave pseudopotential density functional theory method （DFT）, together with quasi-harmonic Debye model. It is found that the zero-temperature transition pressures from anatase to columbite and from rutile to columbite are 4.55 GPa and 19.92 GPa, respectively. The zero-pressure transition temperatures from anatase to rutile and from columbite to rutile are 950 K and 1500 K, respectively. Our results are consistent with the available experimental data and other theoretical results. Moreover, the dependence of the normalized primitive cell volume V/Vo on pressure and the dependences of thermal expansion coefficient α on temperature and pressure are also obtained successfully.

Experimental study of vapor local characteristics in upward low pressure boiling tube

Radial distribution of vapor local parameters, including local void fraction, interfacial velocity, bubblesize, bubble frequency and interfacial area concentration, are investigated through the measurement in an upwardboiling tube using dual-sensor optical probe. In addition, a new local parameter -"local bubble number concentra-tion" is developed on the basis of bubble frequency. The analysis shows that this parameter can reflect bubble numberdensity in space, and has clear physical meaning.

Deformation, Phase Transformation and Recrystallization in the Shear Bands Induced by High-Strain Rate Loading in Titanium and Its Alloys

α-titanium and its alloys with a dual-phase structure （α＋β） were deformed dynamically under strain rate of about 10^4 s^-1. The formation and microstructural evolution of the localized shear bands were characterized by scanning electron microscopy （SEM） and transmission electron microscopy （TEM）. The results reveal that both the strain and strain rate should be considered simultaneously as the mechanical conditions for shear band formation, and twinning is an important mode of deformation. Both experimental and calculation show that the materials within the bands underwent a superhigh strain rate （9×10^5 S^-1） deformation, which is two magnitudes of that of average strain rate required for shear band formation; the dislocations in the bands can be constricted and developed into cell structures; the phase transformation from α to α2 within the bands was observed, and the transformation products （α2） had a certain crystallographic orientation relationship with their parent; the equiaxed grains with an average size of 10 μm in diameter observed within the bands are proposed to be the results of recrystallization.

Phase Desynchronization as a Mechanism for Transitions to High—Dimensional Chaos

Phase is an important degree of freedom in studies of chaotic oscillations. Phase coherence and localization in coupled chaotic elements are studied. It is shown that phase desynchronization is a key mechanism responsible for the transitions from low- to high-dimensional chaos. The route from low-dimensional chaos to high-dimensional toroidal chaos is accompanied by a cascade of phase desynchronizations. Phase synchronization tree is adopted to exhibit the entrainment process. This bifurcation tree implies an intrinsic cascade of order embedded in irregular motions.

Experimental study of power consumption, local characteristics distributions and homogenization energy in gas–liquid stirred tank reactors

In this paper, the power consumption, the vertical local void fraction and the local gas–liquid interfacial area are investigated in the aerated stirred tank reactors(STRs) equipped with a rigid-flexible impeller. Meanwhile, the regressive correlation based on power consumption and interfacial area is proposed. Then a novel homogenization energy(HE = RSDPtm) expression based on power consumption and local interfacial area is redefined and used to indicate the mixing efficiency. The optimal operating mode is selected based on the change of the HE value. This paper can provide research ideas for structural optimization of stirred reactors.

KLT-based local linear prediction of chaotic time series

In the reconstructed phase space, based on the Karhunen-Loeve transformation （KLT）, the new local linear prediction method is proposed to predict chaotic time series. ＆ noise-free chaotic time series and a noise added chaotic time series are analyzed. The simulation results show that the KLT-based local linear prediction method can effectively make one-step and multi-step prediction for chaotic time series, and the one-step and multi-step prediction accuracies of the KLT-based local linear prediction method are superior to that of the traditional local linear prediction.

Quantum Phase Transition for One-Dimensional Spin-1 XXZ Model with Uniaxial Single-Ion-Type Anisotropy

The quantum phase transitions for one-dimensional spin-1 XXZ model with uniaxial single-ion-type anisotropy are investigated by numerical simulation. The Gaussion transition occurred between the Larged-D phase and Neel phase, which is a gapped phase. The results of ground state energy, local order parameter and entanglement entropy agree with each other. The figures for all of the physical observable are shown in the text.

Asymptotic Boundary Forms for Tight Gabor Frames and Lattice Localization Domains

We consider Gabor localization operators ?defined by two parameters, the generating function ?of a tight Gabor frame , indexed by a lattice , and a domain ?whose boundary consists of line segments connecting certain points of . We provide an explicit formula for the boundary form , the normalized limit of the projection functional , where ?are the eigenvalues of the localization operators ?applied to dilated domains , R is an integer and is the area of the fundamental domain. The boundary form expresses quantitatively the asymptotic interactions between the generating function ?and the oriented boundary ?from the point of view of the projection functional, which measures to what degree a given trace class operator fails to be an orthogonal projection. Keeping the area of the localization domain ?bounded above corresponds to controlling the relative dimensionality of the localization problem.

Prediction of shear bands in sand based on granular flow model and two-phase equilibrium

In contrast to the traditional interpretation of shear bands in sand as a bifurcation problem in continuum mechanics,shear bands in sand are considered as high-strain phase(plastic phase) of sand and the materials outside the bands are still in low-strain phase(elastic phase),namely,the two phases of sand can coexist under certain condition.As a one-dimensional example,the results show that,for materials with strain-softening behavior,the two-phase solution is a stable branch of solutions,but the method to find two-phase solutions is very different from the one for bifurcation analysis.The theory of multi-phase equilibrium and the slow plastic flow model are applied to predict the formation and patterns of shear bands in sand specimens,discontinuity of deformation gradient and stress across interfaces between shear bands and other regions is considered,the continuity of displacements and traction across interfaces is imposed,and the Maxwell relation is satisfied.The governing equations are deduced.The critical stress for the formation of a shear band,both the stresses and strains inside the band and outside the band,and the inclination angle of the band can all be predicted.The predicted results are consistent with experimental measurements.

Practical Security of the Continuous-Variable Quantum Key Distribution with Locally-Generated Local Oscillators

Continuous-variable quantum key distribution (CVQKD) with the local local oscillator (LLO) is confronted with new security problems due to the reference pulses transmitted together with quantum signals over the insecure quantum channel. In this paper, we propose a method of phase attack on reference pulses of the LLO-CVQKD with time-multiplexing. Under this phase attack, the phase drifts of reference pulses are manipulated by eavesdroppers, and then the phase compensation error is increased. Consequently, the secret key rate is reduced due to the imperfect phase compensation for quantum signals. Based on the noise model of imperfect phase compensation, the practical security of LLO-CVQKD under phase attack is analyzed. The simulation results show that the practical security is reduced due to the phase attack, yet it is still tight when system parameters are estimated by training signals.