Selective Impact of Dispersion and Nonlinearity on Waves and Solitary Wave in a Strongly Nonlinear and Flattened Waveguide

The waveguide which is at the center of our concerns in this work is a strongly flattened waveguide, that is to say characterized by a strong dispersion and in addition is strongly nonlinear. As this type of waveguide contains multiple dispersion coefficients according to the degrees of spatial variation within it, our work in this article is to see how these dispersions and nonlinearities each influence the wave or the signal that can propagate in the waveguide. Since the partial differential equation which governs the dynamics of propagation in such transmission medium presents several dispersion and nonlinear coefficients, we check how they contribute to the choices of the solutions that we want them to verify this nonlinear partial differential equation. This effectively requires an adequate choice of the form of solution to be constructed. Thus, this article is based on three main pillars, namely: first of all, making a good choice of the solution function to be constructed, secondly, determining the exact solutions and, if necessary, remodeling the main equation such that it is possible;then check the impact of the dispersion and nonlinear coefficients on the solutions. Finally, the reliability of the solutions obtained is tested by a study of the propagation. Another very important aspect is the use of notions of probability to select the predominant solutions.

Fabrication of Crack-Free Flattened Bamboo and Its Macro-/MicroMorphological and Mechanical Properties

This work aimed to help the bamboo industry develop methodology for producing imperfection-free bamboo boards that can serve either decorative or structural benefit to consumers seeking to engage with the bioeconomy.Specifically,softened and slotted bamboo tubes were handled by a roller device with nails to render crack-free flattened bamboo board.Softening temperature and time were optimized herein according to findings regarding chemical composition and board mechanical properties.The optimal softening parameters for saturated steam heat treatment is proved to be 160°C for 8 min.The flattened bamboo board possesses an increased bending strength of 101.5 MPa and a decreased bending modulus of 7.7 GPa,being compared with only-softened bamboo.The corresponding changing mechanism is determined in-depth by the micro-morphological and mechanical results based on in-situ SEM and AFM technologies.Under the action of nails and rolling processes,the bamboo texture becomes compact with crushed and fragmented conduit walls.The resulting cell cavity then becomes stretched and compressed,taking on a morphology which allows for the mechanical penalties associated with flattening to be avoided.According to the micro-mechanical results obtained by AFM,compared with unflatten bamboo,the Young’s modulus of the cell membrane in transverse direction(YT)decreases to 1.00 GPa while the corresponding Young’s modulus in radial direction(YR)increases to 7.29 GPa.

Removing paint from a metal substrate using a flattened top laser

In this paper,we investigate laser cleaning using a flattened top laser to remove paint coating from a metal substrate.Under the irradiation of a flattened top laser,the coating paint of the metal substrate can be removed efficiently by laser induced ablation,stress,and displacement force.The temperature distribution,stress,and displacement are calculated in the coating layer and substrate using finite element analysis.The effects of a Gaussian laser and a flattened top laser and the results of different diameters of laser spot are compared.The investigation shows that the flattened top laser can reduce the substrate damage and enhance the cleaning efficiency.This method meets the need of large area industrial cleaning applications by optimizing the flattened top laser parameters.

Impact Failure of Flattened Brazilian Disc with Cracks——Process and Mechanism

Split Hopkinson pressure bar(SHPB)has been used to study the dynamic failure pattern of flattened mortar Brazilian disc under impact load.Each disc contains several prefabricated cracks paralleled to each other.Dynamic FEM has also been adopted to simulate such failure behavior.The mechanism of crack initiation,propagation and cut-through have been scrutinized with both experimental and numerical approaches.Influence of the number of the prefabricated cracks on the specimen strength and acoustic emission(AE)performance can be observed and studied.The results show that the strength decreases and AE counts increases,when the number of the prefabricated cracks increases.

New High Nonlinear and Dispersion Flattened Photonic Crystal Fiber

A new high nonlinear dispersion flattened photonic crystal fiber is proposed. This fiber has three-fold symmetry core. The doped region in the core and the big air-holes in the 1-st ring can make high nonlinearity in the PCF. And the small air-holes in the 1-st ring and the radial increasing diameters air-holes rings in cladding can be used to turn the dispersion properties of the PCF. We can achieve the optimized optical properties by carefully selecting the PCF's structure parameters. A PCF with flattened dispersion is obtained. The dispersion is within ±0.8 ps·nm-1·km-1 from 1.50 μm to 1.62 μm. The nonlinear coefficient is about 12.645 6 W-1·km-1, the fundamental mode area is about 10.257 9 μm2 and the birefringence is about 3.086 96×10-5 at 1.55 μm. This work may be useful for effective design and fabrication of dispersion flattened photonic crystal with high nonlinearities.

Influence of Intersection Angle of Prefabricated Cracks on Impact Failure of Flattened Brazilian Disc

Both experimental and numerical approaches were used to study dynamic failure properties and patterns of flattened Brazilian discs,containing two prefabricated cracks intersected at a varying angle.Mechanism of crack initiation,propagation,and cut-through were scrutinized and influences of the intersection angle on specimen strength and acoustic emission performance were also studied.All primary cracks initialize near the middle or the tip points of the upper prefabricated crack,and they continue to develop along the load direction and finally cut through the specimen.The secondary cracks could be observed in directions almost horizontal or parallel to the directions of prefabricated cracks.Furthermore,it is found that stress intensity factor reaches its maximum for specimen with intersection angle of 0 degree.

Localized states of flattened quantum elliptic rings and their optical properties

A flattened elliptic ring containing an electron is studied. The emphasis is placed on clarifying the effect of the flattening. The localized states are classified into four types according to their inherent nodes. When the ring becomes more flattened, the total probability of dipole absorption of each state is found to be reduced. Furthermore, each spectral line of absorption is found to shift towards red and may split into a few lines, and these lines as a whole become more diffusive.

Design and Fabrication of a 400 GHz InP-Based Arrayed Waveguide Grating with Flattened Spectral Response

A four-channel 400 GHz channel spacing InP-based arrayed waveguide grating with a flattened wavelength re- sponse by employing a multimode interference coupler at the input waveguide of the filter is prepared. The fabricated devices show a flattened spectral response with a broadened 3-dB bandwidth up to 3.5 nm, interchan- nel non-uniformity of 〈0. 7dB and excellent match to the simulation results.

A design of novel photonic crystal fiber with low and flattened dispersion for supporting 84 orbital angular momentum modes

A dual-guided photonic crystal fiber(PCF) with low and flattened dispersion is designed, which can support a large number of orbital angular momentum(OAM) modes. The properties of the proposed PCF are systematically analyzed through the finite element method. The results show that the proposed PCF can support up to 84 OAM modes with 600 nm bandwidth ranging from 1000 to1600 nm. All values of mode purity are above 91.7%, the isolation parameters are larger than 67 dB and the maximum value up to 145 dB, the lowest confinement loss is only 5×10^(-13) dB·m^(-1).More importantly, the values of dispersion for all modes are less than 40 ps·km-1·nm-1, and the lowest dispersion variation is only 0.7 ps·km^(-1)·nm^(-1). These superior optical properties make the proposed PCF have great advantage in stable transmissions of data and long-distance optical fiber communication system with large capacity.

Engineering ultra-flattened-dispersion photonic crystal fibers with uniform holes by rotations of inner rings

We present a novel method for engineering ultra-flattened-dispersion photonic crystal fibers with uniform air holes by rotations of inner air-hole rings around the fiber core.By choosing suitable rotation angles of each inner ring,theoretical results show that normal,anomalous,and nearly zero ultra-flattened-dispersion fibers in wide spectra ranges of interest can be obtained alternatively.Moreover,in our dispersion sensitive analysis,these types of fibers are robust to variations from optimal design parameters.The method is suitable for the accurate adjustment of fiber dispersion within a small range,which would be valuable for the fabrication of ultra-flattened-dispersion fibers and also have potential applications in wide-band high-speed optical communication systems.

Gain Flattened Raman Fiber Amplifier Using Parameter Optimization and DCF Fiber

We investigate two configurations of Raman fiber amplifier in the 1530-1570 nm region. The gain spectrum variation is decreased from 8.31 dB to 2.48 dB when appropriately adjust the individual two pumps and optical fiber.

Low Cost, High Efficiency, Gain Flattened L Band EDFA Using FBGs as C Band Seed Generators

A low cost, coolerless 980nm diode pumped, gain flattened L band EDFA with fast transient control, high pump efficiency and gain clamping effect was realized by using FBGs as C band seed generators.

Experimental Research on Thermal Performance of Ultra-Thin Flattened Heat Pipes

Ultra-thin flattened heat pipe(UTHP) is an effective solution to solve the problem of high-power density heat dissipation in narrow space. The key factors that determine its thermal performance include: the shapes and sizes of the UTHP, the wick structure, the type of working fluid and its filling ratio. The change in the filling ratio means not only a change in the amount of the working fluid, but also a change in the space distribution of the gas and liquid phases inside the heat pipe. Therefore, it is important to explore the effect of liquid filling ratio on the thermal performance of UTHP. It can provide effective guidance for the production of UTHP. In this work, experiments were conducted on four groups of UTHPs with different mesh wicks under a series of liquid filling ratios. The results demonstrate that the volume of the filling working fluid should account for 22%-37% of the total internal volume of the UTHP to avoid deterioration of heat transfer during the operation of the UTHP. In addition, a prediction model of the evaporator temperature has been established to provide guidance for the application of UTHPs.

On Pattern Avoiding Flattened Set Partitions

Let Π = B1/B2/… /Bk be any set partition of[n]= {1,2,...,n} satisfying that entries are increasing in each block and blocks are arranged in increasing order of their first entries.Then Callan defined the flattened Π to be the permutation of[n]obtained by erasing the divers between its blocks,and Callan also enumerated the number of set partitions of[n]whose flattening avoids a single3-letter pattern.Mansour posed the question of counting set partitions of[n]whose flattening avoids a pattern of length 4.In this paper,we present the number of set partitions of[n]whose flattening avoids one of the patterns：1234,1243,1324,1342,1423,1432,3142 and 4132.

Microstructural Characteristics and Heat Transfer of Flattened Millimeter-size Nickel Droplet

The splat is the fundamental unit of thermally sprayed coatings,which has been one of the hottest issues for decades.In order to study the splat formation,an experiment was designed and conducted,in which a millimeter-size nickel metal droplet fell freely and impacted on aluminum and stainless steel substrate.The microstructural characteristics of the splat and the heat conduction and solidification processes during the flattening process have been studied numerically and experimentally.The effect of the droplet temperature,impact velocity as well as the substrate temperature was investigated.The phenomenon of substrate melting was observed after the spreading of nickel droplet,which became more pronounced when the initial substrate temperature increased.Increasing the impact velocity of droplet resulted in a decrease in the interfacial temperature between droplet and substrate.

拟双曲度量空间中广义反演函数的性质

基于一般度量空间中flattening函数和admission反演函数的概念,在拟双曲度量空间中引入拟对偶的概念,并借助于拟双曲度量作为工具,结合flattening函数和admission反演函数的性质来刻画了拟双曲度量空间中广义反演函数的几何特征。

Extrapolate well logs based on the constrained interpolation algorithm

Based on a detailed analysis of differences between seismic data and well logs, we discuss the problem of matching seismic traces and well logs and present a new matching method based on event search in instantaneous phase which greatly improves seismic resolution. The method is based on flattening events in instantaneous phase to compare the seismic traces to the well log traces with the same phase. We calculate the coefficients using the singular value decomposition method to extrapolate the well logs. As a result, the events in the seismic profile are continuous and match well with well logs. We apply this method to the Mao-2 well in Daqing Oilfield with good results.

Fabrication of flatten grooved-sintered wick heat pipe

With the rapid rising of heat flux and reduction of heat dissipating space of microelectronic devises, flattened sintered heat pipe has become an ideal conducting element of use in the electronic cooling field. A manufacturing technology named phase change flattening process is presented to fabricate the flattened grooved-sintered wick heat pipe （GSHP for short）. Deformation geometry of flattened GSHP and the elasto-plastic deformation of flattening process are analyzed theoretically and verified by experiments. The results show that the vapor pressure inside sintered heat pipe during flattening process is determined by the saturated vapor pressure equation; the width and vapor area of flattened heat pipe change greatly as the flattening proceeds; the maximum equivalent strain distributes at the interface between wick and vapor in the fiat section; the buckling phenomenon can be well eliminated when the flattening temperature reaches 480 K; phase change flattening punch load increases with flattening temperature and displacement.

支持向量机回归模型中目标函数的五个理解

支持向量机回归和支持向量机分类有区别,分类问题主要从最大化两类间的间隔入手,而回归问题则需要寻找适合这批数据的自变量和因变量之间关系的回归方程,使得由回归方程计算出来的因变量值和实际数据中的因变量值尽量接近。并且,支持向量机回归和普通的回归问题还不一样,设定了一个2ε间隔带,在这个间隔带内的数据点、不计算损失,之外的计算损失,在尽量最小化损失的同时,模型的目标函数里多了个1/2‖W‖2,关于这个项,有很多疑问,给支持向量机回归目标函数的理解造成了很大的困难,尤其是在学习了支持向量机分类问题后,更容易把这个项和分类问题中同样的项意味着的最大化间隔相联系,但又不能直接对应上。于是,我们从正则化、结构风险最小化(岭回归、权重衰减)、回归超平面的flatten、二分类问题的转化、回归问题的本质这五个方面着手,从不同的角度进行透彻分析和解释1/2‖W‖2,从而为支持向量机回归模型的目标函数的理解进一步理清思路、扫清障碍。而且,第五个理解站在了新的高度,从问题的本质出发,统一了前面四个理解,也具有自己独特的看法。

Properties of Zero Dispersion Wavelengths in Silica Strands and Photonic Crystal Fibres

To design and calculate the zero-dispersion wavelength is one of the important aspects for highly nonlinear photonic crystal fibres. By using the air filling fraction f defined as f = （ 6d） / （ 2π∧ ） here for the cladding effective index, and the step effective index model, the relationship between the properties of chromatic dispersion and the two different structures has been analysed. It is pointed that the variation of the zero dispersion wavelength is insensitive to the core diameter change in one range of core diameter D, while keeping the air filling fraction f constant. In the other range of core diameter D, the photonic crystal fibres have the best nearly-zero ultraflattened dispersion. These properties are significant to the design of chromatic dispersion and zero dispersion wavelength in photonic crystal fibres.