Finite element analysis of stress distribution and burst failure of SiC_f/Ti-6Al-4V composite ring

A three-dimensional cyclic symmetry finite element model of titanium-matrix composites（TMCs） ring was developed to investigate the stress distribution and burst failure. The effects of fiber volume fractions, reinforced areas, thermal residual stresses and two different temperatures on stress distribution were studied. The burst speed was obtained through analyzing the hoop tensile stresses under a series of rotating speeds. The results indicate that at the two different temperatures, the influences of fiber volume fractions and reinforced areas on stress level and distribution are different. Some proposals are provided for the structure design of the TMCs ring. With regard to thermal residual stresses, a larger reinforced area is an advisable choice for design of the ring at higher temperature.

Designing ultrastable P2/O3-type layered oxides for sodium ion batteries by regulating Na distribution and oxygen redox chemistry

P2/O3-type Ni/Mn-based layered oxides are promising cathode materials for sodium-ion batteries(SIBs)owing to their high energy density.However,exploring effective ways to enhance the synergy between the P2 and 03 phases remains a necessity.Herein,we design a P2/O3-type Na_(0.76)Ni_(0.31)Zn_(0.07)Mn_(0.50)Ti_(0.12)0_(2)(NNZMT)with high chemical/electrochemical stability by enhancing the coupling between the two phases.For the first time,a unique Na*extraction is observed from a Na-rich O3 phase by a Na-poor P2 phase and systematically investigated.This process is facilitated by Zn^(2+)/Ti^(4+)dual doping and calcination condition regulation,allowing a higher Na*content in the P2 phase with larger Na^(+)transport channels and enhancing Na transport kinetics.Because of reduced Na^(+)in the O3 phase,which increases the difficulty of H^(+)/Na^(+) exchange,the hydrostability of the O3 phase in NNZMT is considerably improved.Furthermore,Zn^(2+)/Ti^(4+)presence in NNZMT synergistically regulates oxygen redox chemistry,which effectively suppresses O_(2)/CO_(2) gas release and electrolyte decomposition,and completely inhibits phase transitions above 4.0 V.As a result,NNZMT achieves a high discharge capacity of 144.8 mA h g^(-1) with a median voltage of 3.42 V at 20 mA g^(-1) and exhibits excellent cycling performance with a capacity retention of 77.3% for 1000 cycles at 2000 mA g^(-1).This study provides an effective strategy and new insights into the design of high-performance layered-oxide cathode materials with enhanced structure/interface stability forSIBs.

Angular Distribution of Element Contents in Tree Rings and the Environmental Information

Element contents of tree rings and soils near tree roots collected from Deodar cedar (Cedrus deodara (Roxb.) G. Don) and Masson pine (Picks massoniana lamb.) were determined to study the relationship between the angular distribution of element contents in tree rings and the environmental information. The chemical composition and properties of soils are very much complicated, which leads to the non-uniform distribution of the element contents in tree rings. The statistical multi-variable regression method was used to got the information of the tree-centered distribution of element contents in the environment (soil) (C’), C’(z, θj ), from the distribution of element contents in tree rings (C), C(Z, θi), which depends on the plane azimuth angle (θi), i. e., C=C(Z,θi), where Z is the atomic number of the element, with a satisfactory result,though this study is only a primary one.

Strain distributions and electronic structure of three-dimensional InAs/GaAs quantum rings

This paper presents a finite element calculation for the electronic structure and strain distribution of self-organized InAs/GaAs quantum rings. The strain distribution calculations are based on the continuum elastic theory. An ideal three-dimensional circular quantum ring model is adopted in this work. The electron and heavy-hole energy levels of the InAs/GaAs quantum rings are calculated by solving the three-dimensional effective mass SchrSdinger equation including the deformation potential and piezoelectric potential up to the second order induced by the strain. The calculated results show the importance of strain and piezoelectric effects, and these effects should be taken into consideration in analysis of the optoelectronic characteristics of strain quantum rings.

The Depth Distribution of Constacyclic Codes Over the Ring F_(p)+vF_(p)+v^(2)F_(p)

In this paper,we studied the depth spectrum and the depth distribution of constacyclic codes over the non-chain ring R=F_(p)+vF_(p)+v^(2)F_(p),where v^(3)=v.By decomposing the linear codes C over R into the linear codes over the finite field F_(p),three corresponding constacyclic codes C_(1),C_(2),C_(3) over F_(p)were obtained.Furthermore,considering the depth spectrum of constacyclic codes over the finite filed F_(p),and the relationship between constacyclic codes C_(1),C_(2),C_(3) and C,the depth spectrum and the depth distribution of constacyclic codes over R were discussed.

DISTRIBUTION AND ULTRASTRUCTURAL LOCALIZATION OF CARCINOEMBRYONIC ANTIGEN (CEA) IN SIGNET RING CELLS OF GASTRIC CANCER

The distribution and ultrastructural localization of CEA in signet-ring cells of 15 gastric cancer specimens were observed by PAP and immunoelectron microscopic methods. The mechanism of abnormal distribution of CEA in the signet-ring cell and its biological significance are discussed. The results showed that the CEA positive rate in signet-ring cells was 100% with the polarity lost in distribution. Under the light microscope, the CEA stain patterns were of two types: cytoplasmic and membranous types. The former was predominant. Under the electron microscope, most of the CEA was distributed on the cell membrane and cytoplasm. CEA was found in intracellular membranous structure of the cancer cells, especially in protein synthesis and transport organellae (RER, Golgi Complex etc.). The synthesis of CEA in cancer cells increased, yet its elimination was somewhat hampered. The result was that the RER became extended and were full of CEA (+) material. In the free signet-ring cell, there was a small and short contact plane. The tight junction was severed as the cell junction reduced. The antigenic determinant of CEA was glycoprotein. The abnormal distribution of CEA in signet-ring cells might be the morphologic reflection of the glycosylation of surface glycoprotein of tumor cells.

Contact Pressure Intensity Distribution and Its Effects on Workpiece Flatness Error in Plane Polishing with Retaining Ring

In order to find out the contact pressure intensity distribution and its effects on the workepiece flatness error in plane polishing with retaining ring,the contact model and the boundary conditions are built up based on the axial symmetric elastic contact theory.The pressure intensity distribution is calculated and analyzed with the help of the Hankel transform theory and the constructing solution method of Chebyshev orthogonal polynomials.And then,the effects of the dimensionless ring-workpiece gap,the load ratio of the retaining ring and the dimensionless ring width on the contact pressure intensity distribution are obtained.Finally,based on the distribution theory of material removal volume,the effects of the pressure intensity distributions on the flatness errors of polished workpiece are also investigated experimentally.The results show that the contact pressure intensity distribution becomes more uniform and the better profile of polished workpiece can also be obtained,if the dimensionless ring-workpiece gap is reduced,the load ratio is selected as 0.6 to 0.85,and the dimensionless ring width is taken as 0.13 to 0.40.

Distribution of Virulence-Associated Genes of Avian Pathogenic Escherichia coli Isolates in China

216 avian pathogenic Escherichia coli （APEC） isolates were obtained from poultry with colibacillosis in different areas of China. Among them, 195 were serotyped as 078, 088, and 093. Thirteen virulence-associated genes, including fimC, iucD, iss, tsh, fyuA, irp2, eaeA, hlyE, colV, papC, stx2f, vat, and astA, were submitted to PCR amplification. The fimC gene was the most prevalent with a detection rate of 93.6%, followed by iucD （70.8%）, iss （58.8%）, and tsh （51.4%） in APEC isolates. The detection rate of high pathogenicity islands （HPI）-associatedfyuA and irp2 genes were both 44.9%, with no LEE （the locus of enterocyte effacement） island-associated gene eaeA detected. In terms of distribution patterns of the 13 virulence-associated genes, 5 isolates harborbed 10 genes, 19 isolates contained onlyfimC gene, and only 4 isolates had no virulence-associated gene detected. Different correlations of the virulence-associated genes with O serotypes were also investigated and 50% 078 isolates had a gene distribution patterns of fimC^＋iucD^＋irp2^＋fyuA^＋iss^＋colV^＋tsh^＋.

Characteristics of grain size distribution and the shear strength analysis of Chenjiaba long runout coseismic landslide

Study on the grain size distribution characteristics and the frictional strength behavior of the slide deposits are helpful to disclose the landslide runout process and understand the mechanism of a long runout landslide. We performed grain size distribution analysis on samples collected from Chenjiaba landslide induced by Wenchuan earthquake. The grain size distribution of samples from the landslide sections quantitatively depicts a gradual coarsening upward grading from shear zone to the top section. Then a multistage-multiphase ring shearing approach was used to determine a comparative shear strength behavior of samples from each landslide section. In this method, a sample was sheared continuously for large displacement and fast rate on different normal stress conditions. The multiphase shear mode with a maximum of 105 mm/min rate has allowed observing the qualitative change and patterns of the frictional resistance behaviors of soils under different normal stresses. The results of coefficient of friction values under multiphase shear mode have shown substantial post peak shear weakening behaviors after large shear displacement that can be narrated with long runout processes. The shear strength test results indicate that the shear zone samples have developed higher friction angle values compared to overlying section samples, on the last phase of shear process, which may be very important to understand the braking mechanism of a long runout landslide.

Effect of Partial Root-Zone Irrigating Deuterium Oxide on the Properties of Water Transportation and Distribution in Young Apple Trees

Partial root-zone irrigation （PRI） has been proved to be an optimal water-saving irrigation technology, however, few studies were done on water transportation and distribution under PRI. The present study was performed to investigate the water transportation and distribution among the wet and dry root-zones and the shoot using deuterium water （D2O） in 1/4 root-zone PRI experiment. It also aimed to determine and analyze the D2O relative abundance within different types of roots and shoots. The results indicated that water could be transported from roots in wet root-zone to roots in dry root-zone and shoots within 2 h after irrigation. Water transportation in roots of wet-zone was carried out by absorbing root, 1-2 mm root, 2-5 mm root, and〉5 mm root progressively, while through a reverse process in three dry root-zones. In shoots, water was transported to trunk, central trunk, annual branches, shoot and leaf progressively. Thus in the young apple trees subjected to PRI, water was distributed ifrst in the roots, including the roots in the wet and dry root-zones, to satisfy the water need of roots itself, and then transported to the shoot within hours of irrigation.

Microstructure and Temperature Distribution in ZnAl_2O_4 Sintered Body by Pulse Electric Current

Microstructure of reaction sintering of ZnAl2O4 at 1500℃ by hot-pressing(HP) and pulse electric current was investigated. The results indicated that the existed cracks in sintered body were caused by structure mismatch. It is the evidence that periodical temperature field existed during pulse electric current sintering of nonconductive materials. The distance between high temperature areas was related to die diameter.

Numerical simulation of stress distribution in Al_2O_3-TiC/Q235 diffusion bonded joints

The distributions of the axial stress and shear stress in Al2O3-TiC/Q235 diffusion bonded joints were studied using finite element method （FEM）. The effect of interlayer thickness on the axial stress and shear stress was also investigated. The results indicate that the gradients of the axial stress and shear stress are great near the joint edge. The maximal shear stress produces at the interface of the Al2O3-TIC and Ti interlayer. With the increase of Cu interlayer thickness, the magnitudes of the axial stress and shear stress first decrease and then increase. The distribution of the axial stress changes greatly with a little change in the shear stress. The shear fracture initiates at the interface of the Al2O3-TiC/ Ti interlayer with high shear stress and then propagates to the Al2O3-TIC side, which is consistent with the stress FEM calculating results.

Problems and Solutions for Medium-Voltage Distribution Network in Nanning City

This paper introduces the problems emerged in the developing process of Nanning Medium-voltage distribution network to adapt the progress of HV network. These problems are: (1) unreasonable structure (large amount of radical type 10 kV lines); (2) one 10 kV line for each customer (causing difficulties for line corridors); (3) circuit breaker are widely used for MV customers (result in complicated substation structure); (4) lots of overhead 10 kV lines in urban area. Ring circuit, insulated cables, load break switches, and fast acting fuses etc. advanced technologies are proposed for the retrofit of urban distribution network.

Distributional features of δ^(18) O in precipitation in China

According to calculation on available data, higher δ18O exists in atmospheric precipitation of southeastern and northwestern part of China, and the lower in Northeast China and the southern QinghaiTibet Plateau. In China temperature effect appears mainly in the inner continent of midhigh latitudes and the amount effect appears in southeastern coastal regions, the YunnanGuizhou Plateau and QinghaiTibet Plateau where the influence of monsoon climate is obvious. The meteoric water lines (MWLs) of different regions are of certain divergence, which is closely related to the stable isotopic fractionations of the two processes, namely the evaporation of origins and the precipitating of vapor.

Valence Distribution in AT_xV_(6-X)O_(11) Compounds

The distribution of trivalent and tetravalent cations in several ATxV6-xO11 compounds was quantitatively studied by the bond valence method. In SrV6O11, the M(3) sites were mainly occupied by trivaient cations; while M(1) and M(2) sites were shared by trivalent and tetravalent cations, the relative content of tetravalent at M(1) sites was higher than at M(2) sites. During substitution process, the trivalent cations preferred to occupy M(3) sites, tetravalent ones preferred to occupy M(2) sites. The occupancy of trivalent and tetravalent cations at M sites would change with the substitution

The 0 ,1 - Distribution of the First CoordinateSequences Derived from ML- Sequences over Z/(2~e)

The 0,1 distribution of the first coordinate sequences derived from the maximal lenght sequences (ML sequences) over Z/(2~e) is exactly given.

Impact of PV Distributed Generation on Loop Distribution Network

The rapid spreading of the Photovoltaic (PV) Systems as Distributed Generation (DG) in medium and low voltage networks created many effects and changes on the existing power system networks. In this work, two methods have been used and applied to determine the optimal allocation and sizing of the PV to be installed as DGs (ranging from 250 kW up to 3 MW). The first one is to determine the location according to the maximal power losses reduction over the feeder. The second one is by using the Harmony Search Algorithm which is claimed to be a powerful technique for optimal allocation of PV systems. The results of the two techniques were compared and found to be nearly closed. Furthermore, investigation on the effects on the feeder in terms of voltage levels, power factor readings, and short circuit current levels has been done. All calculations and simulations are conducted by using the MATLAB Simulation Program. Some field calculations and observations have been expended in order to substantiate the research findings and validation.

Distribution of Ag(I), Li(I)-Cs(I) Picrates, and Na(I) Tetraphenylborate with Differences in Phase Volume between Water and Diluents

Ionic strength conditions in distribution experiments with single ions are very important for evaluating their distribution properties. Distribution experiments of picrates (MPic) with M = Ag(I) and Li(I)-Cs(I) into o-dichlorobenzene (oDCBz) were performed at 298 K by changing volume ratios (Vorg/V) between water and oDCBz phases, where “org” shows an organic phase. Simultaneously, an analytic equation with the Vorg/V variation was derived in order to analyze such distribution systems. Additionally, the AgPic distribution into nitrobenzene (NB), dichloromethane, and 1,2-dichloroethene (DCE) and the NaB(C6H5) 4 (=NaBPh4) one into NB and DCE were studied at 298 K under the conditions of various Vorg/V values. So, extraction constants (Kex) for MPic into the org phases, their ion-pair formation constants (KMA,org) for MA = MPic in the org ones, and standard distribution constants () for the M(I) transfers between the water and org bulk phases with M = Ag and Li-Cs were determined at the distribution equilibrium potential (dep) of zero V between the bulk phases and also the Kex (NaA), KNaA,org, and values were done at A-=BPh-4. Here, the symbols Kex, KMA,org, and or were defined as [MA] org/[M+][A-], [MA] org/[M+]org [A-]org, and [M+]org/[M+] or [A-]org/[A-] at dep = 0, respectively. Especially, the ionic strength dependences of Kex and KMPic,org were examined at M = Li(I)-K(I) and org = oDCBz. From above, the conditional distribution constants, KD,BPh4 and KD,Cs, were classified by checking the experimental conditions of the I, Iorg, and dep values.

The Distribution Search:An O(n) Expected Time Search

Provided an algorithm for the distribution search and proves the time complexity of the algorithm. This algorithm uses a mathematical formula to search n elements in the sequence of n elements in O(n)expected time,and experimental reesult proves that distribution search is superior to binary search.

Distributions and Relationships of CO_2,O_2,and Dimethylsulfide in the Changjiang(Yangtze) Estuary and Its Adjacent Waters in Summer

The distributions and relationships of O_2, CO_2, and dimethylsulfide (DMS) in the Changjiang (Yangtze) Estuary and its adjacent waters were investigated in June 2014. In surface water, mean O_2 saturation level, partial pressure of CO_2 (pCO_2), and DMS concentrations (and ranges) were 110% (89%–167%), 374μatm (91–640 μatm), and 8.53 nmol L^(-1) (1.10–27.50 nmol L^(-1)), respectively. The sea-to-air fluxes (and ranges) of DMS and CO_2 were 8.24 μmol m^(-2)d^(-1) (0.26–62.77 μmol m^(-2)d^(-1)), and -4.7 mmol m^(-2)d^(-1) (-110.8-31.7 mmol m^(-2)d^(-1)), respectively. Dissolved O_2 was oversaturated, DMS concentrations were relatively high, and this region served as a sink of atmospheric CO_2. The pCO_2 was significantly and negatively correlated with the O_2 saturation level, while the DMS concentration showed different positive relationships with the O_2 saturation level in different water masses. In vertical profiles, a hypoxic zone existed below 20 m at a longitude of 123?E. The stratification of temperature and salinity caused by the Taiwan Warm Current suppressed seawater exchange between upper and lower layers, resulting in the formation of a hypoxic zone. Oxidative de-composition of organic detritus carried by the Changjiang River Diluted Water (CRDW) consumed abundant O_2 and produced additional CO_2. The DMS concentrations decreased because of low phytoplankton biomass in the hypoxic zone. Strong correlations ap-peared between the O_2 saturation level, pCO_2 and DMS concentrations in vertical profiles. Our results strongly suggested that CRDW played an important role in the distributions and relationships of O_2, CO_2, and DMS.