Influence of magnetically constricted arc traverse speed (MCATS) on tensile properties and microstructural characteristics of welded Inconel 718 alloy sheets

The magnetically constricted arc technique was implemented to mitigate the heat input related metallurgical problems in Gas Tungsten Arc Welding(GTAW)of Inconel 718 alloy particularly Nb segregation and subsequent laves phase evolution in fusion zone.This paper reports the direct effect of magnetically constricted arc traverse speed(MCATS)on bead profile,tensile properties and microstructural evolution of Inconel 718 alloy sheets joined by Gas Tungsten Constricted Arc Welding(GTCAW)process.The mechanism amenable for the microstructural modification and corresponding influence on the tensile properties of joints is investigated both in qualitative and quantitative manner related to the mechanics of arc constriction and pulsing.It is correlated to the solidification conditions during welding.The relationship between MCATS and Arc Constriction Current(ACC)was derived.Its interaction effect on the magnetic arc constriction and joint performance was analysed.Results showed that the joints fabricated using CATS of 70 mm/min exhibited superior tensile properties(98.39% of base metal strength with 31.50% elongation).It is attributed to the grain refinement in fusion zone microstructure leading to the evolution of finer,discrete laves phase in interdendritic areas.

EFFECTS OF S86019, AN ACTIVE COMPONENT FROM PURALIA LOB AT A, ON CELL DIFFERENTIATION AND CELL CYCLE TRAVERSE OF HL-60 CELLS

The effects of S86019, an active component from Puralia lobata, on the induction of cell differentiation and cell cycle traverse of HL-60 cells were described. It was shown that cell proliferation of HL-60 cells was inhibited by S86019 in vitro. Under the action of S86019 the HL-60 cells were induced to differentiate into metamyelocytes, myelocytes and much matured cells with banded or segmented nucleus. Flow cytometry demonstrated that the cell population of HL-60 cells was blocked at G1 phase which resulted in the elevation of percentage of G1 cells and decrease of percentage of cells in S phase. Experimental results demonstrated that S86019 is an active inducer of cell differentiation in HL-60 cells.

Recent Russian remote sensing investigations in Antarctica within the framework of scientific traverses

This paper includes a short historical review of Russian and Soviet scientific traverses to study the Antarctic inland. The first traverse left on April 2, 1956. It resulted in the opening of the first Russian inland research station named Pionerskaya and provided the first geophysical and glaciological data on regions inland of the Antarctic coast. By 1965, a number of regional inland scientific traverses had been completed and. the first Atlas of Antarctica was published in 1966. The atlas presented the main achievements of that time. After the discovery of Lake Vostok, Russian scientists commenced remote sensing investigations to study this unique natural phenomenon. The propagation of acoustic and electromagnetic waves in the glacier near Vostok Station were measured to provide important geophysical data. Radio-echo sounding data showed that Lake Vostok is isolated and separated from the rest of the Antarctic subglacial hydrosphere. The total area of the lake is 15 790 km2, excluding 365 km^2 occupied by 11 islands. Reflection seismic soundings of Lake Vostok estimated a total volume of about 6 100 km^3, an average depth of about 400 m, and a maximum depth of 1 200 m. Since 2008, there have been a number of scientific traverses between Mirny and Vostok stations and between Progress and Vostok stations. The data collected during the traverses have provided new insights into sub-ice topography and ice sheet structure, and have led to the discovery of subglacial lakes near Komsomolskaya Station and under Pionerskaya Station.

Gravity Survey along the Mizuho Traverse Routes, East Antarctica: SEAL Seismic Exploration in 1999-2000

A gravity survey was conducted along the Mizuho traverse routes in austral summer of 1999-2000 by the 41st Japanese Antarctic Research Expedition (JARE-41). The main purpose of the survey was to obtain detail gravity anomaly along the traverse routes, where deep seismic exploration was simultaneously conducted in order to obtain a fine crustal structure of the Mizuho Plateau. By using SCINTREX (CG-3M) gravity meter, the survey was carried out at 160 sites with about 1 km interval in a distance of 190 km from S16 to Z20 on the traverse routes. Free-air and Bouguer anomalies were calculated using precise locations by GPS measurements, by taking into account an effect of the thick icesheet. The furrowed negative Free-air anomalies are identified around H192, where middle points of the whole traverse routes. Two bedrock elevation models derived both by seismic refraction analyses and radio-echo sounding might correspond to the bottom and the top of a mixture layer composed from ice-moraine rocks over the bedrock surface. Thickness of the crust estimated by Bouguer anomalies is 0.5 - 1 km larger toward inland at the terminal point of Z20 along the profile.

The Road Traversed by Lhumao

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Effects of traverse speed on weld formation,microstructure and mechanical properties of ZK60 Mg alloy joint by bobbin tool friction stir welding

ZK60B(Mg-6%Zn-0.6%Zr)alloy joints fabricated by bobbin tool friction stir welding(BTFSW)with various traverse speeds were investigated.The sound joint fabricated by the BTFSW was possible under the appropriate welding parameters.The severe plastic deformation during BTFSW resulted in dispersion and segregation of the Zr-rich particles within the stirred zone(SZ)followed by evolution of a bimodal grain structure with distributed bands of 0.8-1.7μm ultrafine grains and 4.1-7.1μm equiaxed grains.Micro-hardness of SZ is substantially reduced in contrast to that of parent metal(PM)in spite of the finer grain size owing to dissolution of Mg-Zn based precipitates having hardening effects on alpha-Mg matrix.With the decrease in traverse speed,randomization degree of the plasticized metal flow increases,which is evidenced by the randomized arc line pattern at the low traverse speed.Among all defect-free joints,the 200 mm/min joint exhibits the weakest isotropy of texture within SZ and the best tensile properties,which has reduced ultimate tensile strength and yield strength by 5.4% and by 22.2%,respectively,as compared to the PM.The randomized texture hinders the joint fracturing within SZ at low elongation.Therefore,a relatively high elongation of 10.8% was achieved,which corresponded to 72% of the PM value.

REFLECTION OF OBLIQUE INCIDENT WAVES BY PERFORATED CAISSONS WITH TRAVERSE WALL

The interaction of oblique incident waves with infinite number of perforated caissons is investigated. The fluid domain is divided into infinite sub-domains by the caissons, and eigen-function expansion is applied to expand velocity potentials in each domain. A phase relation is introduced for wave oscillation in each caisson, and the structure geometry is considered in constructing the models of reflection waves. The reflected waves with the present analysis include all of the waves traveling in different directions when incident wave period is short. Numerical examinations show that velocities at the inner and outer sides of the front walls of caissons ase close to each other, and reflection coefficients satisfy the energy conservation relation very well when porous effect parameter is infinite. Numerical results show that the reflection coefficients of oblique incident waves are smaller for shorter caissons at low frequency, and decrease with the increase of wave incident angle.

Noncommutative-Geometry Wormholes Based on the Casimir Effect

While wormholes are as good a prediction of Einstein’s theory as black holes, they are subject to severe restrictions from quantum field theory. In particular, holding a wormhole open requires a violation of the null energy condition, calling for the existence of exotic matter. The Casimir effect has shown that this physical requirement can be met on a small scale, thereby solving a key conceptual problem. The Casimir effect does not, however, guarantee that the small-scale violation is sufficient for supporting a macroscopic wormhole. The purpose of this paper is to connect the Casimir effect to noncommutative geometry, which also aims to accommodate small-scale effects, the difference being that these can now be viewed as intrinsic properties of spacetime. As a result, the noncommutative effects can be implemented by modifying only the energy momentum tensor in the Einstein field equations, while leaving the Einstein tensor unchanged. The wormhole can therefore be macroscopic in spite of the small Casimir effect.

轿车尾流移测试验研究

轿车的尾流结构与其空气阻力、升力与安全性有密切联系 ,为进一步研究轿车尾流结构及验证尾流场数值模拟结果的精确性提供依据 ,需通过试验得到较为全面地反映尾流结构的定量信息。为此 ,进行了红旗CA774轿车 1 10模型的七孔探针尾流移测试验 。

陀螺控制导线精度的正确评定

本文推证了陀螺控制导线精度评定的严密公式,并讨论了用误差椭圆来表示最弱点点位精度的方法。所有评定精度的公式均依据最小二乘矩阵平差原理得出,这些公式对正确进行误差预计很有意义。

Exploration of Traversable Wormholes Sustained by an Extra Spatial Dimension

The main goal of this paper is to determine the effect of an extra dimension on a traversable wormhole. Here an earlier study by the author [Phys. Rev. D 98, 064041 (2018)] is extended in several significant ways. To begin with, the extra spatial dimension is assumed to be time dependent, while the redshift and shape functions, as well as the extra dimension, are functions of both r and l, the respective radial and extra coordinates;the last of these is therefore a function of r, l, and t. The main objective is to determine the conditions that allow the throat of the wormhole to be threaded with ordinary matter (by respecting the null energy condition) and that the same conditions lead to a violation of the null energy condition in the fifth dimension, which is therefore responsible for sustaining the wormhole. The dependence of the extra dimension on l and t is subject to additional conditions that are subsequently analyzed in this paper. Finally, the extra dimension may be extremely small or even curled up.

CASIO fx-4500P计算器在建筑工程测量中的应用(下)

9.1 计算导线转折角和 计算器全清零后,找到文件名“GZJH”,进行如下操作:

Science and exploration in the high interior of East Antarctica in the twentieth century

The highest part of the East Antarctic Ice Sheet, more than 4000 m above sea level, has been an area that has seen a considerable scientific research effort undertaken by the Chinese National Antarctic Research Expedition, and its international collaborators, since January 2005. That includes the establishment of the most remote Of the Chinese Antarctic stations, Kunlun, at Dome A in 2009. However, the exploration and mapping of this region had been commenced many decades earlier, most notably by inland traverses of the Union of Soviet Socialist Republics during the 1957-1958 International Geophysical Year 0GY） and later; and the extensive surveys of Antarctic surface and sub-ice topography by airborne radio-echo sounding made by the US National Science Foundation-Scott Polar Research Institute-Technical University of Denmark （NSF-SPRI-TUD） in the late-1960s and the 1970s. Here we provide a history of the activities and achievements of these earlier programs. Recent topographic maps of the ice sheet surface in the Dome A region, produced using Chinese GPS data and satellite altimetry, have shown the maps compiled from the earlier data were remarkably accurate.

Application of Electrical Resistivity Imaging in Investigating Groundwater Pollution in Sapele Area, Nigeria

Sixty-four multi-electrode Lund imaging system coupled with ABEM SAS 4000 Terrameter was used for the electrical imaging of the study area. Wenner and Gradient arrays with 2 m minimum electrode spacing were employed which revealed resistivity changes in the vertical and horizontal directions along the survey lines. Earth imager software was employed for?the processing and the iteration of the 2-D resistivity data. The subsurface is characterized with soil material with resistivity ranging from 42 - 15,000 Ohm-m, reflective of varying degree of conductivity associated with changing lithology and fluid type. Correlation with borehole data shows that the first 10 m is composed of laterite. While sand materials occupy 10 to about 60 m beneath the surface, with anomalously high resistivity ≤15,000 Ohm-m in most parts. These high resistivity formations can be attributed to the presence of hydrocarbon within the subsurface, which is an indication that shallow aquifer in the study area has been polluted. The water level in the study area is close to the surface, between 4 - 5 m. As a result of the high resistivity formations in most parts, deep wells of about 45 m are recommended after geophysical investigations.

Building Traversing NAT IPv6 Tunnel Gateway System Relies on Netfilter/Iptable Framework

The transition from IPv4 to IPv6 is doomed to be a long process. The network Address translation （NAT） technology is used very popularly in IPv4 network to make up the shortage of network address. It is a desiderated problem to make the users behind NAT gateway to access to IPv6 networks. By studying the transition technology from IPv4 to IPv6 and introducing NAT technology in IPv6, a scenario is put forward through 6to4 tunnel The scenario is implemented and the gateway system＇s performance is analyzed.

Friction surfacing of AISI 316 over mild steel: A characteriation study

An attempt has been made with overlaying of stain-less steel on mild steel by the technique of friction surfacing. This investigation elaborates the excellence acquired by different combination of the process parameters used in friction surfacing specifically traverse speed of the cross slide, speed of rotation of the spindle and the uniaxial compressive load. Excellent overlaying has been obtained amongst the chosen materials. To which, the coating can be done with various set of process parameters. It has been observed that the bond strength of the coating was found to be at a maximum of 502 MPa by ram tensile test.Based upon this results the surface methodology was characterized with scanning electron microscope.For authenticating the results, the coated specimen was subjected to salt spray test. The bonding microstructure was characterized using optical microscopy and X-ray diffraction. Corrosion resistance of surfaced coatings was found to be more inferior to that of mechtrode material and greater with the substrate.

Two Types of Features and Their Extractions in Handwritten Chinese Character Recognition

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Simulation of temporal characteristics of ion-velocity susceptibility to single event upset effect

Using a Monte Carlo simulation tool of the multi-functional package for SEEs Analysis （MUFPSA）, we study the temporal characteristics of ion-velocity susceptibility to the single event upset （SEU） effect, including the deposited energy, traversed time within the device, and profile of the current pulse. The results show that the averaged dposited energy decreases with the increase of the ion-velocity, and incident ions of 2~9Bi have a wider distribution of energy deposition than 132Xe at the same ion-velocity. Additionally, the traversed time presents an obvious decreasing trend with the increase of ion-velocity. Concurrently, ion-velocity certainly has an influence on the current pulse and then it presents a particular regularity. The detailed discussion is conducted to estimate the relevant linear energy transfer （LET） of incident ions and the SEU cross section of the testing device from experiment and simulation and to critically consider the metric of LET.

Research Progress of Termite Control with Fipronil

The indoor and field control effect of fipronil against termite was introduced, and the main influencing factors were analyzed, including traverse transfer of fipronil between termite individuals, temperature and proportion of termite exposed to fipronil, synergistic effect of other agents on fipronil, diffusion and degrada- tion of fipronil in soil. The effects of fipronil and metabolites on environment were elaborated.