ASYMMETRICAL STRUCTURES OF THE TEMPERATURE AND HUMIDITY OF TROPICAL CYCLONES

Based on NCEP/CFSR 0.5° reanalysis data and the best track data from the Japan Tokyo Typhoon Center,composite and comparative analyses demonstrate the asymmetrical structures of the temperature and humidity in tropical cyclones over the Western North Pacific and the South China Sea from 1979 to 2010.The results are shown as follows.(1) With intensifying tropical cyclones,the flow field tends to become gradually more axisymmetric;however,the asymmetry of the specific humidity in the outer regions is more obvious.(2) In general,tropical cyclones have a non-uniform,vertical, "double warm-core" structure.The "warm-cores" in the lower level of weak tropical cyclones and in the higher level of strong tropical cyclones are the stronger of the two.(3) The distribution area of a "warm-core" is enhanced with cyclone intensification and tends to become more axisymmetric.At 200 hPa,the "warm-core" of a weak cyclone has a weak anticyclone in the center,whereas that of a strong cyclone has a weak cyclone in the center.(4)The "wet-core" of a tropical cyclone is primarily located in the lower level(700-850 hPa).With the cyclone's intensification,the intensity of the "wet-core" increases and the scope of the 0.8 g kg^(-1) specific humidity anomaly tends to expand to higher levels.(5) With the cyclone's deepening,the pseudo-equivalent potential temperature at different levels in different regions increases.In addition,the largest warming rates at each intensity level in the different regions occur in the core area,followed in turn by the envelope and outer areas.

Stable single longitudinal mode erbium-doped silica fiber laser based on an asymmetric linear three-cavity structure

We present a stable linear-cavity single longitudinal mode （SLM） erbium-doped silica fiber laser. It consists of four fiber Bragg gratings （FBGs） directly written in a section of photosensitive erbium-doped fiber （EDF） to form an asymmetric three-cavity structure. The stable SLM operation at a wavelength of 1545.112 nm with a 3-dB bandwidth of 0.012 nm and an optical signal-to-noise ratio （OSNR） of about 60 dB is verified experimentally. Under laboratory conditions, the performance of a power fluctuation of less than 0.05 dB observed from the power meter for 6 h and a wavelength variation of less than 0.01 nm obtained from the optical spectrum analyzer （OSA） for about 1.5 h are demonstrated. The gain fiber length is no longer limited to only several centimeters for SLM operation because of the excellent mode-selecting ability of the asymmetric three-cavity structure. The proposed scheme provides a simple and cost-effective approach to realizing a stable SLM fiber laser.

Bcklund Transformation and Localized Coherent Structure for the (2+1)-Dimensional Asymmetric Nizhnik-Novikov-Veselov Equation

This article is concerned with the extended homogeneous balance method for studying the abundant localized solution structure of the (2+1) dimensional asymmetric Nizhnik Novikov Veselov equation. A B a¨ cklund transformation was first obtained, and then the richness of the localized coherent structures was found, which was caused by the entrance of two variable separated arbitrary functions, in the model. For some special choices of the arbitrary functions, it is shown that the localized structures of the model may be dromions, lumps, and ring solitons.

Structured illumination microscopy based on asymmetric three-beam interference

Structured illumination microscopy(SIM)is a rapidly developing super-resolution technology.It has been widely used in various application fields of biomedicine due to its excellent two-and three-dimensional imaging capabilities.Furthermore,faster three-dimensional imaging methods are required to help enable more research-oriented living cell imaging.In this paper,a fast and sensitive three-dimensional structured illumination microscopy based on asymmetric three-beam interference is proposed.An innovative time-series acquisition method is employed to halve the time required to obtain each raw image.A segmented half-wave plate as a substantial linear polarization modulation method is applied to the three-dimensional SIM system for the first time.Although it needs to acquire 21 raw images instead of 15 to reconstruct one super-resolution image,the SIM setup proposed in this paper is 30%faster than the traditional spatial light modulator-SIM(SLM-SIM)in imaging each super-resolution image.The related theoretical derivation,hardware system,and verification experiment are elaborated in this paper.The stable and fast 3D super-resolution imaging method proposed in this paper is of great significance to the research of organelle interaction,intercellular communication,and other biomedical fields.

Seismic Responses of Asymmetric Base-Isolated Structures under Near-Fault Ground Motion

An inter-story shear model of asymmetric base-isolated structures incorporating deformation of each isolation bearing was built, and a method to simultaneously simulate bi-directional near-fault and far-field ground motions was proposed. A comparative study on the dynamic responses of asymmetric base-isolated structures under near-fault and far-field ground motions were conducted to investigate the effects of eccentricity in the isolation system and in the superstructures, the ratio of the uncoupled torsional to lateral frequency of the superstructure and the pulse period of near-fault ground motions on the nonlinear seismic response of asymmetric base-isolated structures. Numerical results show that eccentricity in the isolation system makes asymmetric base-isolated structure more sensitive to near-fault ground motions, and the pulse period of near-fault ground motions plays an import role in governing the seismic responses of asymmetric base-isolated structures.

AN ANALYSIS OF THE ASYMMETRICAL STRUCTURE OF TYPHOON AERE'S PRECIPITATION

The structural characteristics of 2004 typhoon Aere's precipitation are analyzed using the high-resolution data from the Tropical Rainfall Measuring Mission(TRMM) of the National Aeronautics Space Administration(NASA).It is found that the typhoon's characteristics vary at different stages of its development.To analyze the asymmetric causation of precipitation distribution,data from the National Center for Environmental Prediction(NCEP) reanalysis are used to calculate the vertical integral of the water vapor flux vector.The results show that because of this process,along with the unique phenomenon of twin-typhoon circulation,the easterly air current of the typhoon's northern side and the southwesterly air current of its southern side play a joint role in transporting water vapor.Furthermore,its transport effects vary greatly at the different stages of development,showing the peculiarity of the water source for this typhoon process.The distributions of the typhoon convection area—characterized by heavy precipitation and a maximum-value area of the water vapor flux,as well as a strong ascending-motion area—differ at different stages of the typhoon's development.The non-uniform distribution of water vapor flux and the vertical motion bring about asymmetrical distribution of the typhoon precipitation.

Asymmetric structure of atomic above-threshold ionization spectrum in two-color elliptically polarized laser fields

According to the frequency-domain theory, we investigate the asymmetric structure of above-threshold ionization(ATI) spectrum of an atom in two-color elliptically polarized(EP) laser fields. When both laser fields are linearly polarized(LP), the spectrum shows that the multi-plateau structure is symmetric about the emitted angle of electron at π/2, while the spectrum becomes asymmetric and shifts rightwards with the increase of the EP degree of the IR laser field. Since the total ATI process is regarded as including direct ATI and the rescattering ATI, we analyze the spectrum structure of direct ATI and rescattering ATI separately. Using the saddle-point approximation, we find that for direct ATI, the fringes on the spectrum are mainly attributed to the fact that the ionization probability becomes very small when the direction of emitted electrons is perpendicular to the direction of the XUV laser polarization;while for the rescattering ATI, the interference fringes on the spectrum mainly come from the superposition of the waist structures on the spectra of all sub-channels.

NUMERICAL EXPERIMENTS OF THE INFLUENCE OF DIABATIC HEATING ON TROPICAL CYCLONE ASYMMETRIC STRUCTURE

Using the barotropic volticity equation that contains forcing from diabatic heating with appropriate parameterization. a number of numerical experiments are conducted for the tropical cyclone that is initially symmetric The result shows that the diabatic heating has important effects on the asymmetric structure in addition to the roll of the β term and nonlinear advection term in its formation. It again confirms the conclusion that the diabatic heating is a possible mechanism responsible for such structures in the tropical cyclone.

A NUMERICAL ANALYSIS ON TYPHOON ASYMMETRIC STRUCTUREAND MOTION

Five prediction experiments are carried out with two typhoons in 1992 using a limited -arca primitiveequations and two-way interactive model in a movable ,nested mesh. The result indicates good agreementin terms of motion between the prediction and observation. Studying the asymmetric structure in the cas-es selected, a close link is uncovered between the temporal evolutions of the structure and the track of motion in a tropical cyclone. Understanding of real asymmetric structure will help to improve the skill offorecasting tropical cyclones.

Effect of the asymmetric geometry on the wake structures of a pitching foil

The two-dimensional wake produced by a time-periodic pitching foil with the asymmetric geometry is investigated in the present work. Through numerically solving nonlinear Navier–Stokes equations, we discuss the relationship among the kinematics of the prescribed motion, the asymmetric parameter K ranged as-1 ≤ K ≤ 1, and the types of the wakes including the mP＋nS wake, the B′enard–von K′arm′an wake, the reverse B′enard–von K′arm′an wake, and the deviated wake.Compared with previous studies, we reveal that the asymmetric geometry of a pitching foil directly affects the foil＇s wake structures. The numerical results show that the reverse B′enard–von K′arm′an wake is easily deviated at K 〈 0, while the symmetry-breaking of the reverse B′enard–von K′arm′an wake is delayed at K 〉 0. Through the vortex dynamic method,we understand that the initial velocity of the vortex affected by the foil＇s asymmetry plays a key role in the deviation of the reverse B′enard–von K′arm′an wake. Moreover, we provide a theoretical model to predict the wake deviation of the asymmetric foil.

Synthesis and Crystal Structure of (R)-4-Hydroxymethyl-2-thioxo Thiazolidine and Its Asymmetric Catalysis

（R）-4-Hydroxymethyl-2-thioxo thiazolidine as a new chiral catalyst in the asymmetric addition of diethylzinc to benzaldehyde was synthesized from （R）-4-hydroxymethyl-2-thioxo thiazolidine carboxylic acid and its crystal structure was determined by X-ray diffraction method. The compound was crystallized in the orthorhombic system, space group P212121 with unit cell dimensions a=0.67253（12） nm; b=0.89164（17） nm; c=1.06146（19） nm, volume 0.6365（2） nm^3; Z=4, calculated denisity 1.557 Mg/m^3; absorption coefficient 0.733 mm^-1; F（000）=312. The X-ray crystal structure analysis reveals that the compound has a thione group.

The role of viscoelastic damping on retrofitting seismic performance of asymmetric reinforced concrete structures

The primary purpose of this research is to improve the seismic response of a complex asymmetric tall structure using viscoelastic(VE) dampers. Asymmetric structures have detrimental effects on the seismic performance because such structures create abrupt changes in the stiffness or strength that may lead to undesirable stress concentrations at weak locations. Structural control devices are one of the effective ways to reduce seismic impacts, particularly in asymmetric structures. For passive vibration control of structures, VE dampers are considered among the most preferred devices for energy dissipation. Therefore, in this research, VE dampers are implemented at strategic locations in a realistic case study structure to increase the level of distributed damping without occupying significant architectural space and reducing earthquake vibrations in terms of story displacements(drifts) and other design forces. It has been concluded that the seismic response of the considered structure retrofitted with supplemental VE dampers corresponded well in controlling the displacement demands. Moreover, it has been demonstrated that seismic response in terms of interstory drifts was effectively mitigated with supplemental damping when added up to a certain level. Exceeding the supplemental damping from this level did not contribute to additional mitigation of the seismic response of the considered structure. In addition, it was found that the supplemental damping increased the total acceleration of the considered structure at all floor levels, which indicates that for irregular tall structures of this type, VE dampers were only a good retrofitting measure for earthquake induced interstory deformations and their use may not be suitable for acceleration sensitive structures. Overall, the research findings demonstrate how seismic hazards to these types of structures can be reduced by introducing additional damping into the structure.

SYNTHESIS AND STRUCTURE OF AN ASYMMETRIC TRICOBALT COMPOUND Co_3(o-HOC_6H_4S)_2(o-OC_6H_4S)_2(PEt_3)_3

Compound Co_3(o-HOC_6H_4S)_2(o-OC_6H_4S)_2(PEt_3)_3 was obtained by reaction of CoCl_2, o-HOC_6H_4SH(H_2mD)and PEt_3 in ethanol in the presence of NaOCH_3.The three Co atoms are triangularly arranged and asymmetrically bridged by four S and one O atoms from the four H_2mp ligands and terminally ligated by one O and three P atoms.Two free hydroxyl groups form two internal hydrogen bonds with adjacent oxo donor atoms.

Asymmetric reversible structural switching of a diene coordination polymer promoted by UV-visible light

In natural and artificial systems,reversible reactions are commonly asymmetric with respect to the time scale and nature of the stimuli which drive the forward and backward processes.In applications for which switching behavior is required,it is desirable that the reversible reaction goes as close to symmetric as possible;however,such systems are uncommon.Herein,we report an example of ultraviolet(UV)-visible light-regulated asymmetric reversible structural switching involving a diene-based coordination polymer,CP1 and its monocyclobutane product,CP1a.It is possible to cycle at least ten times through a forward [2+2] photocycloaddition reaction and the reverse,photocleavage reaction.A single cycle can be completed within a few minutes.The transformation is accompanied by fast and distinct fluorescence changes,arising from optimisation of the reaction conditions.Density functional theory calculations allow rationalisation of the asymmetric reversible transformation between CP1 and CP1a rather than between CP1 and its dicyclobutane product CP1b.This work provides a clear illustration of reversible structural switching which approaches symmetric behaviour with respect to reaction rate and stimuli.The insights gained from this work also assist in the design of fast,reversible switching materials.

Recent Advances in Asymmetric Structural Composites for Excellent Electromagnetic Interference Shielding:A Review

Since electromagnetic pollution is detrimental to human health and the environment,numerous efforts have been successively made to achieve excellent electromagnetic interference shielding effectiveness(EMI SE)via designing the hierarchical structures for electromagnetic interference(EMI)shielding polymer composites.Among the plentiful structures,the asymmetric structures are currently a hot spot,principally categorizing into multi-layered,porous,fibrous,and segregated asymmetric structures,which endows the high EMI shielding performance for polymer composites incorporated with magnetic,conductive,and/or dielectric micro/nano-fillers,due to the“absorption-reflection-reabsorption”shielding mechanism.Therefore,this review provides the retrospection and summary of the efforts with respect to abundant asymmetric structures and multifunctional micro/nano-fillers for enhancing EMI shielding properties,which is conducive to the booming development of polymeric EMI shielding materials for the promising prospect in modern electronics and 5-generation(5G)technology.

Asymmetric Regulation System Fit for Chinese Telecom Market

After the new round of restructuring of Chinese telecom sector,it's pressing to formulate and implement asymmetric regulation policies so as to shape an effectively competitive market structure in a relatively short term.This paper reviewed the asymmetric regulation policies and practices carried out in foreign telecom market,and then according to the specific situations of Chinese telecom market,proposed the principles and corresponding policies for establishing an asymmetric regulation system fit for Chinese telecom market.

Probing the structure of multi-center molecules with odd–even high harmonics

We study high-order harmonic generation（HHG） from multi-center asymmetric linear molecules numerically and analytically. Our simulations show that odd and even HHG spectra of the asymmetric multi-center system respond differently to the change of the molecular structure. Specifically, when the internuclear distances between these nuclei of the molecule have a small change, the odd spectra usually do not change basically, but the even spectra differ remarkably. Based on this phenomenon, a simple procedure is proposed to probe the positions of these nuclei with odd–even HHG. Our results shed light on attosecond probing of the structure of multi-center molecules using HHG.

Recent Progress on Asymmetric Carbon- and Silica-Based Nanomaterials: From Synthetic Strategies to Their Applications

Carbon-and silica-based nanomaterials possess a set of merits including large surface area,good structural stability,diversified morphology,adjustable structure,and biocompatibility.These outstanding features make them widely applied in different fields.However,limited by the surface free energy effect,the current studies mainly focus on the symmetric structures,such as nanospheres,nanoflowers,nanowires,nanosheets,and core-shell structured composites.By comparison,the asymmetric structure with ingenious adjustability not only exhibits a larger effective surface area accompanied with more active sites,but also enables each component to work independently or corporately to harness their own merits,thus showing the unusual performances in some specific applications.The current review mainly focuses on the recent progress of design principles and synthesis methods of asymmetric carbon-and silica-based nanomaterials,and their applications in energy storage,catalysis,and biomedicine.Particularly,we provide some deep insights into their unique advantages in related fields from the perspective of materials’structure-performance relationship.Furthermore,the challenges and development prospects on the synthesis and applications of asymmetric carbon-and silica-based nanomaterials are also presented and highlighted.