EFFECT OF EQUAL-CHANNEL ANGULAR PRESSING ON STRUCTURE OF Al ALLOY 2024

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Characteristics of viscous debris flow in a drainage channel with an energy dissipation structure

A new type of drainage channel with an energy dissipation structure has been proposed based on previous engineering experiences and practical requirements for hazard mitigation in earthquakeaffected areas.Experimental studies were performed to determine the characteristics of viscous debris flow in a drainage channel of this type with a slope of 15%.The velocity and depth of the viscous debris flow were measured,processed,and subsequently used to characterize the viscous debris flow in the drainage channel.Observations of this experiment showed that the surface of the viscous debris flow in a smooth drainage channel was smoother than that of a similar debris flow passing through the energy dissipation section in a channel of the new type studied here.However,the flow patterns in the two types of channels were similar at other points.These experimental results show that the depth of the viscous debris flow downstream of the energy dissipation structure increased gradually with the length of the energy dissipation structure.In addition,in the smooth channel,the viscous debris-flow velocity downstream of the energy dissipation structure decreased gradually with the length of the energy dissipation structure.Furthermore,theviscous debris-flow depth and velocity were slightly affected by variations in the width of the energy dissipation structure when the channel slope was 15%.Finally,the energy dissipation ratio increased gradually as the length and width of the energy dissipation structure increased;the maximum energy dissipation ratio observed was 62.9%(where B = 0.6m and L/w = 6.0).

Preparation of Chiral Silica Nanostructures with Radial Pores through Single-templating Approach

A chiral low-molecular-weight gelator(LMWG) L-16Ala5PyPF6 was synthesized from L-alanine, which can cause physical gel in n-propanol, ethyl acetate, butylene oxide, water, benzene, 1,4-dioxane and chloroform. The sol-gel reactions were carried out in a mixture of stronger ammonia water and n-propanol at the volume ratio of 2:8. Single-handed twisted silica nanostructures with pore channels vertical to the wall surfaces were first prepared through a single-templating approach comparing with the reported double template method. The formation mechanism of radial pore structure was studied by transmission electron microscopy at different reaction time intervals, which indicated that the radial pore structure was formed via a structural transition in the sol-gel transcription process.

Geologic-Geophysical Indicators of the Deep Structure of Zones of Geothermal Anomalies for Allocation of Channels of the Deep Heat and Mass Transfer

On the basis of the analysis of field thermogeochemical data along abnormal zones of a thermal stream in the Bukhara-Khiva, oil-and-gas region of the Turan (Tegermen, Chagakul, Shimoly Alat, Beshtepa) was succeeded to obtain important data on a deep structure of sites. Data of gas-chemical and geothermal observations show about confinedness of abnormal concentration of methane to zones of the increased values of the temperature field the measured values of temperatures (Tegermen Square and others). On geoelectric section mines 2-D of inversion of the MT-field depth of 4000 m are lower, among very high-resistance the chemogenic and carbonate deposits of the Paleozoic is traced the subvertical carrying-out abnormal zone. This zone is identified as the channel of a deep heat and mass transfer with which hydrocarbon (HC) deposits are connected. It is shown that electro-investigation when using a geophysical complex can and has to become “advancing” at exploration by oil and gas.

Monitoring of Real-Time Complex Deformed Shapes of Thin-Walled Channel Beam Structures Subject to the Coupling Between Bi-Axial Bending and Warping Torsion

Structural health monitoring(SHM)is a research focus involving a large category of techniques performing in-situ identification of structural damage,stress,external loads,vibration signatures,etc.Among various SHM techniques,those able to monitoring structural deformed shapes are considered as an important category.A novel method of deformed shape reconstruction for thinwalled beam structures was recently proposed by Xu et al.[1],which is capable of decoupling complex beam deformations subject to the combination of different loading cases,including tension/compression,bending and warping torsion,and also able to reconstruct the full-field displacement distributions.However,this method was demonstrated only under a relatively simple loading coupling cases,involving uni-axial bending and warping torsion.The effectiveness of the method under more complex loading cases needs to be thoroughly investigated.In this study,more complex deformations under the coupling between bi-axial bending and warping torsion was decoupled using the method.The set of equations for deformation decoupling was established,and the reconstruction algorithm for bending and torsion deformation were utilized.The effectiveness and accuracy of the method was examined using a thin-walled channel beam,relying on analysis results of finite element analysis(FEA).In the analysis,the influence of the positions of the measurement of surface strain distributions on the reconstruction accuracy was discussed.Moreover,different levels of measurement noise were added to the axial strain values based on numerical method,and the noise resistance ability of the deformation reconstruction method was investigated systematically.According to the FEA results,the effectiveness and precision of the method in complex deformation decoupling and reconstruction were demonstrated.Moreover,the immunity of the method to measurement noise was proven to be considerably strong.

Study about the Asymmetry Competing Channel Structure under Bargaining Power

On the problem of competing channel structure, we present asymmetry competing channel structure models under bargaining power, analyze the evolving process of channel structure under different bargaining power and product nature, find different bargaining power and product nature important role for channel structure, and also present equilibrium result. Furthermore, the academic proof for channel structure choice is presented.

Study Competition Channel Structure Based on the Differences of Cost and Products

The purpose of this paper is to expand Trivedi’s study on the influence of channel structure ,which based on product difference, to cost difference; and analyze the evolution course of channel structure under different conditions. We find that like product difference, cost difference have important influence on the choice of channel structure. This paper has improved the present result and provided proof for the choice of channel structure under different environments.

A Novel Layered Complex with Rhomboidal Channels:Hydrothermal Synthesis,Crystal Structure,and Properties of Cu(4,4'-bipy)_2(H_2PO_4)_2(H_2O)_2 (bipy=bipyridine)

The combination of both 4,4′-bipyridine(4,4′-bipy) and dihydrogen phosphate anion ligands with copper(Ⅱ) results in the formation of a novel layered compound Cu(4,4′-bipy)_2(H_2PO_4)_2(H_2O)_2. The crystal structure comprises discrete neutral Cu(4,4′-bipy)_2(H_2PO_4)_2(H_2O)_2 units. The copper atom,located on the crystallographic twofold axis,is coordinated with two nitrogen atoms of terminal 4,4′-bipy ligands and two water molecules at the equatorial positions,and two dihydrogen phosphate oxygen atoms at the axial positions,forming an elongated octahedron. The complex is a two-dimensional distorted rhomboidal network possessing two kinds of rhomboids with dimensions of ca . 1.6792 nm×0.3203 nm and 1.2778 nm×0.3198 nm,respectively. The two-dimensional networks are stacked parallelly on each other along c -axis to give an extended three-dimensional channel network with an interlayer distance of ca . 0.5030 nm. Crystal data: triclinic,space group P -_1,a =1.0253(2) nm,b =1.4501(3) nm,c =0.79715(16) nm, α =97.91(3)°,β = 90.99(3)° ,γ =85.54(3)°,V =1.1703(4) nm 3,Z =2,R =0.0892,wR =0.2451.

Impact of depth ratio on flow structure and turbulence characteristics of compound open channel flows

Compound open channel flows appear in most natural rivers are of great importance in river management and flood control.In this study,large eddy simulations were carried out to simulate the compound open channel flows with four different depth ratios(hr=0.10,0.25,0.50,and 0.75).The main flow velocity,secondary flow,Reynolds stress,and bed shear stress were obtained from numerical simulations.The depth-averaged stream wise momentum equation was used to quantify the lateral momentum exchange between the main channel and floodplain.The instantaneous coherent structures were presented by the Q criterion method.The impact of hr on flow structure and turbulence charac-teristics was analyzed.The results showed that with the increase of hr,the high velocity area in the main channel shifted to the floodplain,and the dip phenomenon became more obvious;the Reynolds stress largely contributed to the lateral momentum exchange within the flows near the side walls of floodplain;and the vortex structures were found to significantly increase in the floodplain region.

Helix-like structure formation of a semi-flexible chain confined in a cylinder channel

Molecular dynamics method is used to study the conformation behavior of a semi-flexible polymer chain confined in a cylinder channel.A novel helix-like structure is found to form during the simulation.Moreover,the detailed characteristic parameters and formation probability of these helix-like structures under moderate conditions are investigated.We find that the structure is not a perfect helix,but a bundle of elliptical turns.In addition,we conduct a statistical analysis for the chain monomer distribution along the radial direction.This research contributes to our understanding of the microscopic conformation of polymer chains in confined environments filled with a solvent.

Theoretical and Experimental Optimization of InGaAs Channels in GaAs PHEMT Structure

The ground-state energy level （GEL） and electron distribution of GaAs pseudomorphic high-electron-mobility transistors （PHEMTs） are analyzed by a self-consistent solution to the Schrodinger-Poisson equations. The indium composition and thickness of the InGaAs channel are optimized according to the GEL position. The GEL position is not in direct proportion to 1/d^2 （d is the channel thickness） by considering the influence of electron distribution in the InGaAs channel. Indium composition 0.22 and channel thickness 9 nm are obtained by considering the mismatch between InGaAs and AlGaAs. Several PHEMT samples are grown according to the theoretical results and mobility 6300 cm^2 /V.s is achieved.

A Receiver Structure for Frequency-Flat Time-Varying Rayleigh Channels and Performance Analysis

This paper proposes a wavelet based receiver structure for frequency-flat time-varying Rayleigh channels, consisting of a receiver front-end followed by a Maximum A-Posteriori (MAP) detector. Discretization of the received continuous time signal using filter banks is an essential stage in the front-end part, where the Fast Haar Transform (FHT) is used to reduce complexity. Analysis of our receiver over slow-fading channels shows that it is optimal for certain modulation schemes. By comparison with literature, it is shown that over such channels our receiver can achieve optimal performance for Time-Orthogonal modulation. Computed and Monte-Carlo simulated performance results over fast time-varying Rayleigh fading channels show that with Minimum Shift Keying (MSK), our receiver using four basis functions (filters) lowers the error floor by more than one order of magnitude with respect to other techniques of comparable complexity. Orthogonal Frequency Shift Keying (FSK) can achieve the same performance as Time-Orthogonal modulation for the slow-fading case, but suffers some degradation over fast-fading channels where it exhibits an error floor. Compared to MSK, however, Orthogonal FSK provides better performance.

The Channel Maps and the Position-Velocity Diagrams of Multi-core Structure of Cepheus C

The first important problem in the star forming process is the formation of proto star core in star forming regions of molecular cloud. The multi core structure in star forming regions is related to the forming of proto star core. The molecular radiation of C 18 O( J = 1-0) in Cepheus C has been observed. The C 18 O( J = 1-0) observations form the basis for an interesting study on the cloud cores and star formation activity in the cores of the Cepheus C. In order to study the multi core structure of C 18 O( J = 1-0) in the Cepheus C the channel maps and the position velocity diagrams of C 18 O( J = 1-0) will be shown. From the maps it is found that the contour level and distribution size of the three cores in Cepheus C are related to the channel velocity very much. The channel velocity of C 18 O( J = 1-0) molecules in core b, which distributed in all the channels velocity, is different with one in core a and core c very much. The C 18 O( J = 1-0) molecules in core a and core c of the Cepheus C mostly distributed in the blue shifted channel velocity relating to peak velocity, and only in -10.0 ～ -9.5 km/s, which is the red shifted channel velocity relating to peak velocity. And the contour level of C 18 O( J = 1-0) in -10.0 ～ -9.5 km/s is small and the distrbution size in the channel map is small. According to the position velocity diagrams the asymmetry of the distribution both blue shifted and red shifted components should reflect the asymmetry of the profile. From the diagrams it also is found that the contour level and the distribution size of the three cores are different from each other. Both results from the maps and diagrams are coincident with each other.

Study about the Competing Channel Structure under Bargaining Power

From the bargaining process, competing channel structure models are presented. The evolving process of channel structure under different bargaining power is analyzed The important role of different bargaining power is discussed and the equilibrium result is found. Also the theoretical evidences for competing channel structure choice are given.

Heat Transfer and Friction Characteristics of Printed Circuit Heat Exchangers with Different Channel Structures for S-CO_(2) Power System

Printed circuit heat exchanger(PCHE)has been widely used in supercritical carbon dioxide(S-CO_(2))power systems because of its high heat transfer efficiency and good compactness.However,due to the large variety of PCHE configurations,channel selection in practical applications lacks a basis.Therefore,this paper discussed the heat transfer and friction characteristics and the synergy of three fields in the channel under the guidance of the field synergy principle for four typical PCHE channels.Additionally,the comprehensive performance of four channels was compared.Finally,the heat transfer and friction factor correlations for S-CO_(2)in four channels were established.The findings demonstrate that the synergy of velocity and pressure fields of the straight channel PCHE is better(β≈180°),so its resistance loss is relatively small.The zigzag and sinusoidal wavy channels and the airfoil fins can reduce the angle a between the temperature gradient and velocity,thus enhancing the heat transfer.The sinusoidal wavy channel can reduce flow resistance compared to the zigzag channel due to the rounded corners.The streamlined airfoil structure can guide the flow and reduce backflow,thus reducing resistance losses.In the range of Re studied in this paper,the maximum error of the proposed heat transfer and friction factor correlations of PCHE is 7.0%,which shows good fitting accuracy.The research in this paper can provide a reference for the selection and design of PCHE with different channel configurations.

Imaging shallow structure with active-source surface wave signal recorded by distributed acoustic sensing arrays

Distributed acoustic sensing(DAS) is one recently developed seismic acquisition technique that is based on fiber-optic sensing. DAS provides dense spatial spacing that is useful to image shallow structure with surface waves.To test the feasibility of DAS in shallow structure imaging,the PoroTomo team conducted a DAS experiment with the vibroseis truck T-Rex in Brady’s Hot Springs, Nevada, USA.The Rayleigh waves excited by the vertical mode of the vibroseis truck were analyzed with the Multichannel Analysis of Surface Waves(MASW) method. Phase velocities between5 and 20 Hz were successfully extracted for one segment of cable and were employed to build a shear-wave velocity model for the top 50 meters. The dispersion curves obtained with DAS agree well with the ones extracted from co-located geophones data and from the passive source Noise Correlation Functions(NCF). Comparing to the co-located geophone array, the higher sensor density that DAS arrays provides help reducing aliasing in dispersion analysis, and separating different surface wave modes. This study demonstrates the feasibility and advantage of DAS in imaging shallow structure with surface waves.

Solvothermal Synthesis and Crystal Structure of a Layered Thioantimonate(Ⅲ) [C_4H_9NH_3]_2Sb_4S_7

An inorganic-organic hybrid thioantimonate（Ⅲ） [CH3（CH2）3NH3]2Sb4S7 1 with layered structure was synthesized by solvothermal method. 1 crystallizes in the triclinic system, space group P1 with a = 7.0124（11）, b = 11.919（2）, c =14.879（3）A, α = 108.791（3）, β= 102.441（3）, γ = 92.846（2）°, V= 1140.1（3）A3, Mr = 859.71, Z= 2, Do = 2.504 g/cm^3 ,μ = 5.324 mm^-1, F（000） = 804, S = 1.013, the Final R = 0.0297 and wR = 0.0618 for 3534 observed reflections with Ⅰ 〉 2 σ（Ⅰ）. 1 consists of [C4HgNH3]＋ cations and two-dimensional [Sb4ST]n^2n- anion which is composed of three SbS3 trigonal pyranaids and one SbS4 unit joined by sharing common comers. The anionic layers are stacked perpendicularly to the c axis of the unit cell forming two-dimensional channels between the layers. The [C4H9NH3]^＋ cations interdigitate in a bilayer and reside in the 2D channels leading to a sandwich-like arrangement of the anion and cations.

Seismic performance analysis and design suggestion for frame buildings with cast-in-place staircases

Many staircases in reinforced concrete （RC） frame structures suffered severe damage during the Wenchuan earthquake. Elastic analyses for 18 RC structure models with and without staircases are conducted and compared to study the influence of the staircase on the stiffness, displacements and internal forces of the structures. To capture the yielding development and damage mechanism of frame structures, elasto-plastic analysis is carried out for one of the 18 models. Based on the features observed in the analyses, a new type of staircase design i.e., isolating them from the master structure to eliminate the effect of K-type struts, is proposed and discussed. It is concluded that the proposed method of staircase isolation is effective and feasible for engineering design, and does not significantly increase the construction cost.

Syntheses and Crystal Structures of 12-Oxime Dehydroabietic Acid Derivatives

Three novel dehydroabietate oxime derivatives were synthesized from dehydroabietic acid and their crystal structures were determined by X-ray crystallographic techniques. All of these 12-oxime dehydroabietic acid derivatives crystallize in orthorhombic system, space group P212121. In the structures, rings A and B exhibit chair and half-chair configurations, respectively and form trans ring junction with two methyl groups（C（19） and C（20）） in the axis positions. The oxime groups have E conformations. Comparison of conformations reveals subtle differences principally in ring B due to the modification in C（12）. The E-acetaldehyde oxime derivative 2c showed distinct BKα gate-opening activity with an ionic current increase of 164% at 30 μM versus the control current.

3D Velocity Structure and Its Tectonic Implications in the East China Sea and Yellow Sea

3D structure of the crust and upper mantle in the studied area has been analyzed from surface wave tomography. The velocity distribution in the uppermost crust is symmetrical on two sides of the central line of the sea, and coincides with the structure of crystalline basement. The essential difference in tectonics between the East China Sea and the Yellow Sea mainly lies in that the velocity structures of their lower crust and upper mantle are identical to those of South China and North China respectively. In the upper mantle there exists a high-velocity zone with a nearly EW strike from the Hangzhou Bay, China, to the Tokara Channel, Japan, along about the latitude of 30°N. It is found that between the East China Sea and the Yellow Sea there are systematical differences in geomorphology, geology, seismicity, heat flow, quality factor and gravity and aeromagnetic anomalies, which is related to both left-lateral shear dislocation and right-lateral tear of the Benioff zone from the Hangzhou Bay to the Tokara Channel.It is inferred that the East China Sea was formed by Cenozoic back-arc extension. The boundary between the North China and South China crustal blocks stretches along the southern piedmont of Mts. Daba-Dabie-Hangzhou Bay-Tokara Channel, and the subduction zone at the Okinawa trench is the eastern boundary of the South China crustal block. The movements of the Pacific plate, Indian plate and upper mantle rather than the Philippine plate subduction have played a dominant role for the modern tectonic movements in East Asia.