Effects of interstitial cluster mobility on dislocation loops evolution under irradiation of austenitic steel

The evolution of dislocation loops in austenitic steels irradiated with Fe^(+)is investigated using cluster dynamics(CD)simulations by developing a CD model.The CD predictions are compared with experimental results in the literature.The number density and average diameter of the dislocation loops obtained from the CD simulations are in good agreement with the experimental data obtained from transmission electron microscopy(TEM)observations of Fe~+-irradiated Solution Annealed 304,Cold Worked 316,and HR3 austenitic steels in the literature.The CD simulation results demonstrate that the diffusion of in-cascade interstitial clusters plays a major role in the dislocation loop density and dislocation loop growth;in particular,for the HR3 austenitic steel,the CD model has verified the effect of temperature on the density and size of the dislocation loops.

苏云金芽胞杆菌杀虫晶体蛋白Cry1Ba结构域Ⅱ中Loops结构与功能关系研究

为了明确杀虫晶体蛋白中各个Loop的结构与功能的关系,以及Loop突变对Cry1Ba蛋白杀虫活性的影响,首先通过三维结构模拟以及同源序列分析的方法,找到Cry1Ba蛋白三个结构域及三个Loop相对应的氨基酸片段;然后通过重叠引物PCR将编码Cry1Ba蛋白结构域Ⅱ中的三个Loop进行了相应的突变,共获得了5个突变体M1(Loop1:340WSNTR344—缺失(Cry1A))、M2(Loop2:402Y—G)、M3(Loop2:400GIYLEP405—PSAV(Cry3A))、M4(400GIYLEPIH407—ILGS(Cry1A))、M5(Loop3:472LQSRV476—AGAVYTL(Cry1A))。将这些突变体在大肠杆菌BL21中进行了诱导表达,提取蛋白,分别对小菜蛾进行了生物活性测定。生测结果表明,Loop1的缺失突变M1的毒力,与Cry1Ba(LC500.96μg/mL)相比,显著降低,LC50为35.51μg/mL;在Loop2的突变中,单个氨基酸的突变M2(Y/G)的毒力略有下降(LC50为1.31μg/mL);而另两种突变(M3和M4)对小菜蛾的毒力明显下降,LC50值分别为11.56μg/mL、34.81μg/mL;Loop3的突变M5对小菜蛾的毒力略有提高(LC500.81μg/mL),但差异不显著。对Cry1Ba蛋白突变前后结构与功能之间关系的分析结果表明,Loop区突变对Cry1Ba蛋白的结构和功能影响非常显著;Loop1和Loop2在决定Cry1Ba对小菜蛾的毒性方面起着重要作用。

EFFECT OF FIBER FAILURE ON QUASI-STATIC UNLOADING/RELOADING HYSTERESIS LOOPS OF CERAMIC MATRIX COMPOSITES

The two-parameter Weibull model is used to describe the fiber strength distribution.The stress carried by the intact and fracture fibers on the matrix crack plane during unloading/reloading is determined based on the global load sharing criterion.The axial stress distribution of intact fibers upon unloading and reloading is determined based on the mechanisms of fiber sliding relative to matrix in the interface debonded region.The interface debonded length,unloading interface counter slip length,and reloading interface new slip length are obtained by the fracture mechanics approach.The hysteresis loops corresponding to different stresses considering fiber failure are compared with the cases without considering fiber failure.The effects of fiber characteristic strength and fiber Weibull modulus on the fiber failure,the shape,and the area of the hysteresis loops are analyzed.The predicted quasi-static unloading/reloading hysteresis loops agree well with experimental data.

猪圆环病毒二型Capsid表面五倍轴loops的研究进展

猪圆环病毒1型(PCV1)与猪圆环病毒2型(PCV2)的核苷酸序列高度同源,但两者的Cap蛋白结构存在较大差异且PCV1不致病。通过近年来研究两者Cap蛋白结构的文献以及比对PCV1与PCV2病毒颗粒表面五倍轴的三段loops氨基酸序列及蛋白3D结构模拟展示结果,观察Loop BC,Loop DE以及Loop HI的潜在功能和作用,本综述目的在于进一步揭示PCV2 virus-like particles(VLPs)组装及其细胞入侵分子机理,有助于PCV2疫苗及药物载体等的研究与开发,为PCV2疫苗、药物载体等研究与开发奠定理论基础。

Line-integral representations for extended displacements, stresses,and interaction energy of arbitrary dislocation loops in transversely isotropic magneto-electro-elastic bimaterials

In addition to the hexagonal crystals of class 6 mm, many piezoelectric materials （e.g., BaTiO3）, piezomagnetic materials （e.g., CoFe2O4）, and multiferroic com-posite materials （e.g., BaTiO3-CoFe2O4 composites） also exhibit symmetry of transverse isotropy after poling, with the isotropic plane perpendicular to the poling direction. In this paper, simple and elegant line-integral expressions are derived for extended displace-ments, extended stresses, self-energy, and interaction energy of arbitrarily shaped, three-dimensional （3D） dislocation loops with a constant extended Burgers vector in trans-versely isotropic magneto-electro-elastic （MEE） bimaterials （i.e., joined half-spaces）. The derived solutions can also be simply reduced to those expressions for piezoelectric, piezo-magnetic, or purely elastic materials. Several numerical examples are given to show both the multi-field coupling effect and the interface/surface effect in transversely isotropic MEE materials.

Vascular Loops and Neuro-Otologic Symptoms: Is There Any Correlation?

Objective: To determine the relationship between vascular loops in the internal auditory canal and otologic symptoms. Methods: We performed a retrospective study, with a systematic review of the literature and analyzed the magnetic resonances imaging (MRI) of 91 patients attended in the ENT department since April to June 2013, in order to correlate radiological findings with otologic symptoms. Results: Vascular loops were seen in the internal auditory canal of patients without clinical symptoms;however an association was found between the presence of vascular compression of the eighth nerve displayed on MRI and the presence of sensorineural hearing loss and tinnitus. No association was found between vertigo and vascular loops. Conclusion: The presence of vascular loops in the internal auditory canal may be an incidental finding in MRIs of patients without clinical symptoms. However, in patients with tinnitus or sensorineural hearing loss that is unexplained by other clinical pathologies, these may be correlated with the existence of vascular loops which compress the eighth cranial nerve or contact the bone wall of the internal auditory canal. Further studies involving a larger number of patients are required to accurately evaluate the association between these symptoms and vascular loops.

A Sensitivity Mapping Technique for Tensile Force and Case Depth Characterization Based on Magnetic Minor Hysteresis Loops

In the nondestructive testing and evaluation area,magnetic major hysteresis loop measurement technology are widely applied for ferromagnetic material evaluation.However the characterization ability of major hysteresis loop measurement technology greatly varies as the evaluated target properties.To solve this limitation,magnetic minor hysteresis loops,which reflect the responses of ferromagnetic material magnetization in a systematic way,is recommend.Inspired by plenty of information carried by the minor loops,the sensitivity mapping technique was developed to achieve the highest sensitivity of minor-loop parameters to the nondestructively evaluated targets.In this study,for the first time,the sensitivity mapping technique is used to measure the tensile force in a steel strand and evaluate the effective case depth in induction-hardened steel rods.The method and procedures for the sensitivity mapping technique are given before experimental detection.The obtained experimental results indicate that the linear correlation between the induced voltage(or the magnetic induction intensity)and the tensile force(or effective case depth)exists at most of the locations in the cluster of minor loops.The obtained sensitivity maps can be used to optimize the applied magnetic field(or excitation current)and the analyzed locations at the minor loops for achieving the highest sensitivity.For the purpose of tensile force measurement,it is suggested that the strand should be firstly magnetized to the near-saturation state and then restored to the remanent state.In this way,the highest sensitivity is obtained as about 15.26 mV/kN.As for the induction-hardened steel rods,the highest sensitivity of magnetic induction intensity to the effective case depth occurs under low magnetic field conditions and the absolute value of the highest sensitivity is about 0.1110 T/mm.This indicates that if the highest sensitivity is required in the case depth evaluation,the induction-hardened steel rods are only required to be weakly magnetized.The proposed sensitivity mapping technique shows the good performance in the high-sensitivity evaluation of tensile force and case depth in ferromagnetic materials and its application scope can be extended to other nondestructive detection fields.

CMOS analog and mixed-signal phase-locked loops: An overview

CMOS analog and mixed-signal phase-locked loops(PLL)are widely used in varies of the system-on-chips(SoC)as the clock generator or frequency synthesizer.This paper presents an overview of the AMS-PLL,including:1)a brief introduction of the basics of the charge-pump based PLL,which is the most widely used AMS-PLL architecture due to its simplicity and robustness;2)a summary of the design issues of the basic CPPLL architecture;3)a systematic introduction of the techniques for the performance enhancement of the CPPLL;4)a brief overview of ultra-low-jitter AMS-PLL architectures which can achieve lower jitter(<100 fs)with lower power consumption compared with the CPPLL,including the injection-locked PLL(ILPLL),subsampling(SSPLL)and sampling PLL(SPLL);5)a discussion about the consideration of the AMS-PLL architecture selection,which could help designers meet their performance requirements.

High-frequency structure design and RF stability analysis of a 4-vane radio frequency quadrupole with pi-mode stabilizer loops

Compact accelerator-based neutron source facilities are garnering attention and play an important and expanding role in material and engineering sciences,as well as in neutron science education and training.Neutrons are produced by bombarding a low-energy proton beam onto a beryllium or lithium target.In such an acceleratorbased neutron source,a radio frequency quadrupole(RFQ)is usually utilized to accelerate a high-intensity proton beam to a few MeV.This study mainly covers the highfrequency structure design optimizations of a 4-vane RFQ with pi-mode stabilizer loops(PISLs)and its RF stability analysis.A 176 MHz RFQ accelerator is designed to operate at a 10%duty factor and could accelerate an80 mA proton beam from 65 keV to 2.5 MeV within a length of 5.3 m.The adoption of PISLs ensures high RF stability,eases the operation of the accelerator,and implies less stringent alignment and machining tolerances.

量子Loop代数U_(q)(L(sl_(2)))的单权模

用构造的方法解决量子Loop代数U_(q)(L(sl_(2)))具有一个一维权空间的单权模的结构问题,得到了任意一个具有一维权空间的单权模必同构于U_(q)(L(sl_(2)))的四类单权模之一.此外,还构造了一类权空间维数为2的既非最高权也非最低权的量子Loop代数U_(q)(L(sl_(2)))的单权模.

Three-dimensional surface current loops in broadband responsive negative refractive metamaterial with isotropy

We propose a bulk negative refractive index （NRI） metamaterial composed of periodic array of tightly coupled metallic cross-pairs printed oR the six sides of a cube for applications of superlenses. The structural characteristics of the three-dimensional （3D） metamaterial consist in the high symmetry and the superposition of metallic cross-pairs, which can increase the magnetic inductive coupling between adjacent cross-pairs and realize a broadband and isotropic NRI. The proposed 3D structure is simulated using the CS~ Microwave Studio 2006 to verify the design validity. The simulation results show that the proposed structure can not only realize simultaneously an electric and magnetic response to an incident electromagnetic （EM） wave, but also exhibit a broadband NRI whose relative bandwidth can reach up to 56.7%. In addition, the NRI band is insensitive to tile polarization and the incident angle of the incident EM wave. Therefore, the proposed metamaterial is a good candidate material as three-dimensional broadband isotropic NRI metamaterial.

THE ANALYSIS METHOD OF THE SETS OF BRANCHES BASED ON INDEPENDENT LOOPS IN THE ELECTRIC NETWORK

The matrix D describing relations of the loops to the nodes in the graph and also the setsof branches based on the independent loops and their matrix Q are defined.The theorem in whichthe product of the loop-node matrix D multiplied by the incidence matrix Aa is equal to matrix Qis put forward and proved.The admittance matrix Ylc of the sets of the branches is defined and it isassumed that the vector Vlc of voltage of the sets of branches to be a calculative quantity.The equa-tion of the sets of branches is derived and the analysis method of the sets of branches based on theindependent loops in the electric network is presented.

Error Correction Circuit for Single-Event Hardening of Delay Locked Loops

In scaled CMOS processes, the single-event effects generate missing output pulses in Delay-Locked Loop (DLL). Due to its effective sequence detection of the missing pulses in the proposed Error Correction Circuit (ECC) and its portability to be applied to any DLL type, the ECC mitigates the impact of single-event effects and completes its operation with less design complexity without any concern about losing the information. The ECC has been implemented in 180 nm CMOS process and measured the accuracy of mitigation on simulations at LETs up to 100 MeV-cm2/mg. The robustness and portability of the mitigation technique are validated through the results obtained by implementing proposed ECC in XilinxArtix 7 FPGA.

BIFURCATIONS OF TWISTED HOMOCLINIC LOOPS FOR DEGENERATED CASES

In this paper,the bifurcation problems of twisted and degenerated homoclinic loop for higher dimensional systems are studied.Under the nonresonant condition,the existence,uniqueness,and incoexistence of the 1-homoclinic loop and 1-periodic orbit near Γ are obtained,and the inexistence of the 2-homoclinic loop and the existence of 2-periodic orbit near Γ are also given.

RUMINATE METHOD-SOFTWARE PIPELINING ON NESTED LOOPS

This paper offers a new method to solve the problem of software pipelininsr on nested loops. We first introduce our new software pipelininog method. Ruminate Method, which can optimize program with nested loops. We also outline an algorithm to realize it and introduce the hardware support we designed. The performance of Ruminate Method is analyzed at the end of this paper with the aid of our preliminary experimental result.

Factors Affecting the Squareness of Hysteresis Loops of Sintered NdFeB Magnets

Investigation into the magnets with different squareness of hysteresis loop(SHL) reveals that the microstructure of sintered NdFeB magnets has great effects on the SHL of the magnets. The abnormal grain growth deteriorates the SHL seriously. The shape of the grain and the grain boundary affect the intensity of demagnetization field, and consequently on the SHL. The added elements have effects on the phase structures and distributions in the magnets, which influences the uniform of demagnetization field.

STATIC CORRECTION MODES IN DYNAMICAL SIMULATION OF FLEXIBLE MULTIBODY SYSTEM WITH CLOSED LOOPS

By use of the recursive formulation of flexible multibody system with closed loops,this paper studies the dynamic simulation of complicated multibody system.The conception of static correction modes in structural dynamics is introduced to present the local deformation effects due to reaction forces at kinematic joints.A space four bar mechanism is utilized here as an example to describe the method of selecting static correction modes.Compared with vibration normal modes, static correction modes are demonstrated to be effective in numerical simulation.

Random crystal field effect on hysteresis loops and compensation behavior of mixed spin-(1,3/2) Ising system

Magnetic hysteresis and compensation behavior of a mixed spin-（1, 3/2） Ising model on a square lattice are investigated in the framework of effective field theory based on a probability distribution technique. The effect of random crystal field, ferromagnetic and ferrimagnetic exchange interaction on hysteresis loops and compensation phenomenon are discussed. A number of characteristic phenomena have been reported such as the observation of triple hysteresis loops at low temperatures and for negative values of random crystal field. Critical and double compensation temperatures have been also found. The obtained results are also compared to some previous works.

The Positions and Number of Flux Loops and Magnetic Probes for the HT-7U Superconducting Tokamak

The plasma shape and other paremeters such as /3P, li is important for the tokamak deveice where the plasma has a non-circular cross-section of sufficient elongation. The measuered signals of magnetic probes and flux loops are used to reconstruct the plasma shape and the current profile in device operation and plasma shape feed back control system. So the number and positions of magnetic probes and flux loops provides the basis of the plasma reconstruction. This paper instroduce how to use EFIT code (equilibrium fitting code) to determine the number and positions of the magnetic probes and flux loops. The simulation result is given also.

The hysteresis loops of a ferroelectric bilayer film with surface transition layers

Based on the transverse Ising model in the framework of the mean field approximation, this paper discusses a ferroelectric bilayer film with the surface transition layers within each constituent slab and an antiferroelectric interracial coupling between two slabs. The hysteresis loop of a bilayer film is investigated. The results show that the surface transition layer in a ferroelectric bilayer film plays a significant role in realizing the multiple-state memory.